Propranolol, sometimes referred to as “Inderal” (brand name), is a non-cardioselective sympatholytic beta blocker that was first synthesized by British scientist James Black in 1964. As a non-selective beta blocker, propranolol prevents endogenous catecholamines (e.g. norepinephrine and epinephrine) from activating Beta-1 and Beta-2 adrenergic receptors within the CNS (central nervous system) and PNS (peripheral nervous system).
The action of propranolol upon beta receptors makes the medication useful for the treatment of medical conditions such as: high blood pressure (i.e. hypertension); performance anxiety; irregular heart rate; thyrotoxicosis; capillary hemangiomas; hyperhidrosis; and essential tremor. Occasionally, propranolol is also prescribed as a prophylactic for: migraine, cluster headache, and cerebrovascular conditions.
While it is known that propranolol is a low-cost, safe, and effective medication for many medical conditions, some prospective users may be concerned about its side effect profile. A side effect with which many prospective propranolol users are concerned about is weight gain; they want to know whether the medication might cause weight gain – and if so, the amount to expect.
Does Propranolol cause weight gain? (And if so, how much?)
Yes. Evidence supports the idea that propranolol can cause weight gain in a subset of users. However, at this time, it remains unknown as to what percentage of users experience clinically relevant weight gain (7% increase in body weight from baseline) as a side effect of treatment. In other words, your odds of experiencing weight gain while taking propranolol aren’t known.
From 1987 to 2014, The Netherlands Pharmacovigilance Center (Lareb) received just 10 reports of significant weight gain associated with propranolol. Because there were only 10 reports of significant weight gain from propranolol over a 27-year period, this might indicate that weight gain is an extremely uncommon adverse reaction to propranolol.
Furthermore, in 5 of the 10 Lareb case reports, patients who exhibited weight gain had been using concurrent medications – many of which are known to cause weight gain. This considered, it’s possible that propranolol was not the primary inducer of weight gain in 50% of these cases, meaning incidence of weight gain as a reaction to propranolol might be even lower than one would expect.
- Case reports: ~19.84 lbs. (4.4 lbs. to 35.27 lbs.)
- Large trials: ~5.07 lbs. (within 1 year) & ~6.61 lbs. (within 2 years); 27% of users gain more than 11 lbs. within 1 year
- Moderate trials: 3% body weight increase (within 12 months or less)
- Small trials: ~13.22 lbs. (within 6 months); 8% of users
- Beta blockers (clinical trial data): ~2.64 lbs. (average gain associated with all beta blockers – not just propranolol)
Researchers Estemalik and Tepper discussed the U.S. Guidelines for migraine treatment in 2013 and mentioned that while propranolol is associated with weight gain – exact rates of weight gain among propranolol users haven’t been determined. A review of literature by Taylor (2008) indicated that propranolol can trigger weight gain in some users, however, an estimated percentage of users wasn’t noted.
In a small-scale study by Maggioni et al. (2005), 1 of 13 propranolol users (8%) gained significant weight (~13.22 lbs.) over a 6-month period. A large-scale randomized controlled trial by Diener et al. (2004) reported an average body weight increase of 2.3% from baseline – among 179 patients receiving propranolol (160 mg/day) for up to 12 months; this weight gain was significantly greater than the placebo users and topiramate users.
A paper by Pischon and Sharma (2001) noted that “beta blockers” could cause an average weight gain of 2.64 lbs. by reducing metabolic rate and altering energy metabolism, however, propranolol was not specifically discussed. Other studies with large sample sizes conducted by Rao et al. (2000) and Gawel et al. (1992) reported weight gain as a side effect of propranolol over 3-month and 4-month spans, respectively.
A case report by Martinez et al. (1993) noted 19.84 lbs. over a 9-month period in a 44-year-old female propranolol user. Additionally, a small study by Shimell et al. (1990) reported significant weight gain in 13.79% of propranolol users (4 of 29).
Another large-scale study by Rossner (1990) reported that 27% of propranolol users gained more than 11 lbs. after 1 year of treatment. Considering the fact that weight gain is reported in nearly every study in which the effect of propranolol on body weight is assessed, it’s apparent that propranolol can cause weight gain in a subset of users.
Propranolol & Weight Gain (Reasons It Might Happen)
Even though many individuals will use propranolol successfully and experience zero change in body weight, a small percentage of users will end up gaining a significant amount of weight during treatment. Data from large-scale, long-term studies and case reports indicates that clinically relevant weight gain (7% body weight increase from baseline) can occur while taking propranolol.
In the event that you experience noticeable weight gain as a side effect of propranolol, below are some hypothetical explanations for the propranolol-induced weight increase. While reading the explanations below, it is necessary to understand that the mechanism(s) by which propranolol causes weight gain aren’t fully understood – and may be subject to interindividual variation.
Appetite increase: A subset of propranolol users have noted increased appetite as a side effect of the medication. Some users claim that the medication makes them feel “hungry all the time,” starving, or ravenous – such that all they can think about is their next meal.
If your appetite increases while using propranolol, this could definitely lead you to consume more food (i.e. calories) than you did before taking propranolol. Consuming a greater number of calories per day (compared to pre-propranolol) might account for some of your weight gain on this medication.
Bloating & constipation: Several anecdotes from propranolol users online claim that the medication makes them feel bloated and/or constipated. Obviously if you end up bloated and/or constipated while using propranolol, one or both of these side effects could explain some of your weight gain.
Bloating refers to increased water retention throughout the body, which might cause a fat or puffy appearance in certain areas of the body. Anyone who experiences severe bloating on propranolol might gain several pounds in water weight (from the increased water retention).
Constipation refers to infrequent bowel movements and/or difficulty emptying the bowels – usually due to slowed movement of food through the digestive tract. Anyone who experiences constipation on propranolol might notice a weight increase due to the accumulation of stools. (That said, neither bloating or constipation are common side effects of propranolol and therefore are unlikely to be culpable for most user’s weight gain).
Brown adipose tissue (BAT) thermogenesis disruption: Researchers speculate that the non-selective action of propranolol upon beta receptors might disrupt brown adipose tissue (BAT) thermogenesis – which could lead to weight gain. Thermogenesis is a key action of BAT that involves the production of heat following exposure to cold OR excessive calorie intake via diet.
Studies in animal models consistently reveal that knocking out beta receptors can lead to cold intolerance and obesity. Researchers speculate that by inhibiting beta receptors, particularly beta-1 and beta-3 receptors, propranolol treatment might promote weight gain – by simultaneously reducing metabolic rate and increasing fat storage (especially following consumption of high-fat foods).
Cognitive deficits: Because propranolol lowers arousal via reducing sympathetic tone (and stimulatory neurotransmitters), some persons will experience cognitive deficits and/or foggy thinking. Anyone who experiences cognitive deficits and/or “brain fog” as a side effect of propranolol could end up gaining weight as an indirect byproduct of cognitive dysfunction.
Cognitive dysfunction could impair self-regulation (or self-control) around food, as well as interfere with one’s ability to plan healthy meals. If you are unable to control yourself around food (e.g. avoiding overconsumption, staying away from calorie-dense foods) and/or stop planning healthy meals while using propranolol – it could be that cognitive deficits are [indirectly] promoting weight gain.
Depression: Because propranolol can cause depression as a side effect, it’s possible that depression might lead a subset of users to gain weight during treatment. A literature review and meta-analysis by Patten (1990) noted that propranolol treatment induced depression significantly more frequently than other medications administered in antihypertensive trials.
In the event that you become depressed while taking propranolol, the resulting depression might: increase your appetite, reduce your metabolic rate, cause lethargy (making it difficult to exercise), and/or lead to overeating (as a coping mechanism). For this reason, anyone who gains weight on propranolol should reflect upon whether the medication is causing depression – as even mild depression could account for weight gain.
Fatigue: Many individuals using propranolol experience fatigue and/or lethargy as a side effect of the medication. The fatigue and lethargy could lead to reduced: exercise tolerance, intensity, or length. If you’re so fatigued from propranolol that you’re not exercising with the same frequency, intensity, and/or duration as before treatment – then you’ll burn fewer calories than you did before treatment and exhibit a slower metabolic rate.
Fatigue might also decrease non-exercise activity thermogenesis, leading to decreases in energy expenditure and resting metabolic rate. Burning fewer total calories per day and exhibiting a slower metabolic rate (than before using propranolol) due to fatigue could lead to significant weight gain – especially if you’re consuming the same number of calories (as you did pre-treatment).
Gut bacteria modulation: It is known that many prescription medications can directly or indirectly affect concentrations of microbes in the gut. Because gut bacteria can affect things like: appetite/hunger, cognition, hormone production, and fat storage – it’s possible that weight gain among some propranolol users could be related to modulation of gut bacteria.
Perhaps an increase in pathogenic bacteria could: stimulate appetite, cause food cravings, increase fat storage, and/or decrease resting metabolic rate. Although the effect of propranolol on the gut microbiome remains unclear, this could be a mechanism by which the medication promotes weight gain.
Hormonal modulation: Weight gain among some propranolol users could be due to its effect on the production of hormones like testosterone. A study by Rosen et al. (1988) reported that administration of propranolol significantly reduced concentrations of free and total testosterone throughout the body in healthy males – other studies have reported similar findings.
Additionally, it is thought that propranolol might alter hormones such as: insulin, estrogen, cortisol, prolactin, epinephrine, and norepinephrine. Because propranolol significantly reduces testosterone (and may modulate other hormones), it’s reasonable to speculate that this hormonal modulation could lead to: changes in body composition (fat gain, muscle loss) and reduced energy expenditure (via slowing of resting metabolic rate) – each of which could account for unwanted weight gain.
Increased fat storage: Several studies indicate that propranolol may significantly decrease fat oxidation (i.e. fat metabolism). Decreased fat oxidation can lead to positive energy balance, particularly among individuals who consume high-fat diets – resulting in the accumulation of extra unwanted body fat.
Furthermore, the increased fat storage may be accompanied by mild muscle loss due to reduced muscle innervation (related to decreased sympathetic tone). The combination of increased body fat storage coupled with muscle loss could deleteriously affect: hormone levels (e.g. testosterone, estrogen, etc.), gut bacteria, resting metabolic rate, and food preferences – ultimately explaining some of your weight gain.
Reduced efficacy & tolerance of exercise: As a beta blocker, propranolol reduces activation of the sympathetic nervous system which makes it difficult to maximize exercise intensity and/or endurance – regardless of whether the exercise performed is aerobic or strength training. According to Head et al. (1995), propranolol increases exercise difficulty by dose-dependently interfering with substrate metabolism during exercise.
Moreover, it’s possible that the reduction in sympathetic tone induced by propranolol could yield decreased total physical activity (including non-exercise activity thermogenesis). If you find that the intensity and/or length of your workouts is reduced, or that you’re unable to tolerate as much exercise while taking propranolol, this could: decrease your energy expenditure, alter your hormones, slow your metabolic rate, modulate your body composition – and cause weight gain.
Slower metabolism: It seems as though propranolol may reduce resting metabolic rate (relative to body weight) for a subset of users, and this reduction may promote weight gain. Research by Tremblay et al. (1992) discovered that the administration of propranolol significantly reduced resting metabolic rate (and lipid oxidation) in trained individuals – by blocking beta adrenergic receptors.
Earlier research by Christin et al. (1989) reported that propranolol infusions decreased resting metabolic rate among persons with low abdomen to thigh (A/T) ratios. This suggests that individuals in better physical shape may be more prone to slowing of resting metabolic rate while under the influence of propranolol – compared to obese persons.
Nevertheless, slowed resting metabolic rate while using propranolol might be related to: depression, fatigue, hormone changes, and/or reduced physical activity. If your resting metabolic rate slows considerably from propranolol, your body will burn fewer calories than usual – even if you’re consuming the same number of calories as you were pre-treatment.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/2725282
- Source: https://www.ncbi.nlm.nih.gov/pubmed/1337012
Social eating: Certain individuals may use propranolol as an intervention for social anxiety and/or neuropsychiatric conditions that lead to social withdrawal and/or isolation. Assuming propranolol effectively counteracts unwanted symptoms of anxiety (or another neuropsychiatric disorder), a user may become more social and/or participate in more social events.
Because going out to eat is a popular social activity, it’s possible that a subset of persons who respond well to propranolol for anxiety – end up going out to eat more frequently with friends and/or acquaintances than in the past. Dining out with greater frequency (while using propranolol) could lead to weight gain as a result of high calorie foods and/or large portion sizes at many restaurants.
Thyroid hormone modulation: Propranolol might cause weight gain in part through modulation of thyroid hormone concentrations. Research by Franklyn et al. (1985) suggests that propranolol treatment affects thyroid concentrations in euthyroid patients by modulating the peripheral conversion of thyroxine (T4) to T3.
In euthyroid propranolol users, treatment leads to increases in free T4, reverse T3, and TBPA – with slight decreases in free T3 and TBG. Other research by Murakami et al. (1993) indicates that propranolol dose-dependently exhibits anti-thyroid activity.
Considering the modulatory effect of propranolol upon thyroid hormone concentrations, it’s reasonable to surmise that this could be a mechanism by which propranolol induces weight gain. If you’re gaining weight on propranolol, have your thyroid levels checked to ensure that the medication hasn’t caused weight gain via induction of subclinical hypothyroidism.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/3920853
- Source: https://www.ncbi.nlm.nih.gov/pubmed/8104735
Note: There might be different and/or additional explanations as to why someone might experience weight gain while using propranolol (from those listed above). If you’re aware of additional ways by which propranolol might cause weight gain, feel free to document them in the comments.
Propranolol & Weight Gain (The Studies)
Included below are summaries of studies in which the effect of propranolol on body weight was assessed, documented, and/or discussed. As of current, it seems as though nearly all large-scale studies involving propranolol indicate that weight gain can occur as a side effect – especially when administered over a long-term.
Understand that while there may be some limitations associated with the studies below, the data provided by these studies are unambiguous in suggesting that propranolol usage causes weight gain. If you’d like more details about a particular propranolol study that was discussed in this article, simply click on the outbound hyperlink cited listed beneath the study that you’re interested in.
2014: Propranolol and weight gain.
In November 2014, The Netherlands Pharmacovigilance Centre Lareb (an agency that identifies risks and adverse reactions associated with pharmaceutical medications) published a series of 10 case reports in which significant weight gain was noted as an adverse reaction to propranolol. The 10 case reports are briefly described below with letters “A” through “J.”
Understand that because this is a series of case reports rather than data from randomized controlled trials, it is unclear as to how frequently weight gain occurs as a side effect of propranolol. Moreover, it is necessary to emphasize the possibility that, in several of these case reports, weight gain may have been partially or fully attributable to concurrent medication use and/or an undiagnosed medical condition.
- Case A: Case “A” involved a female receiving propranolol at a dosage of 80 mg per day for migraine. The patient experienced significant weight gain after the initiation of propranolol treatment. It was noted that the patient had been concurrently using ethinylestradiol and lynestrenol – each of which should be considered as confounds.
- Case B: Case “B” involved a female receiving propranolol at a dosage of 80 mg per day. The patient’s reason for using propranolol was not known, and the time to onset of weight gain (after propranolol initiation) was not documented. No additional medications were administered with propranolol.
- Case C: Case “C” involved a male receiving propranolol (10 mg per day) for the management of vegetative dystonia. He experienced significant weight gain of 28.66 lbs. within 2 months of treatment. However, the patient was also using paroxetine, a serotonergic antidepressant that is known to cause weight gain as a side effect. In this case, it is unclear as to how influential propranolol was in causing weight gain relative to paroxetine.
- Case D: Case “D” involved a female receiving propranolol (10 mg per day) for migraine. The patient exhibited significant weight gain and fatigue within 4 weeks of treatment. It was noted that her weight gain was counteracted with levothyroxine, however, it was not documented as to whether the patient had a preexisting thyroid condition.
- Case E: Case “E” involved a female receiving propranolol (80 mg per day) for pain. Significant weight gain occurred, however, the time to onset of weight gain [following initiation of propranolol] was not mentioned. Furthermore, the patient had been using other medications with propranolol including: ethinylestradiol plus lynestrenol, and diclofenac.
- Case F: Case “F” involved a male receiving propranolol along with a variety of other medications including: quetiapine, oxazepam, venlafaxine, and sertraline. Although the patient gained a significant amount of weight while using propranolol, it is unknown as to what extent propranolol contributed to his weight gain – especially considering that other medications used (e.g. quetiapine and sertraline) are associated with weight gain.
- Case G: Case “G” involved a female receiving propranolol (40 mg per day) for hypertension. This patient used propranolol for a period of several months and gained 35.27 lbs. (16 kg). As a result of the excessive weight gain in such a short duration, the patient discontinued propranolol.
- Case H: Case “H” involved a female receiving propranolol (80 mg per day) for migraine – along with eletriptan. It was noted that this patient had a history of obesity, however, her weight was stable prior to the initiation of propranolol treatment. Furthermore, the patient claimed that no dietary changes were made while taking propranolol that would’ve accounted for the weight gain.
- Case I: Case “I” involved a female receiving propranolol (80 mg per day) for a period of 2 weeks. In just 2 weeks, the patient gained 13.22 lbs. (6 kg), and as a result, discontinued propranolol treatment. Following propranolol discontinuation, the patient lost 11.02 lbs. (5 kg). It was noted that this patient had previously used propranolol and gained 45 lbs. (12 kg) – none of which could be attenuated via dietary modification. After previously discontinuing propranolol (following the 26.45 lb. gain), the patient reported losing 28.66 lbs. (13 kg).
- Case J: Case “J” involved a female receiving propranolol (80 mg per day) – along with solifenacine. Over a span of months, the patient gained 22.04 lbs. (10 kg). Continuation of treatment resulted in zero weight change following the initial 22.04 lb. gain, and her original weight was not recovered.
According to Lareb, weight gain is not documented in the SmPC (Summary of Product Characteristics) associated with propranolol. The 10 case reports outlined above were collected from the database of Netherlands Pharmacovigilance Centre Lareb from October 1987 to July 2014.
Based on the 10 case reports above, researchers noted: (1) onset of weight gain usually occurred several months following the initiation of propranolol treatment; (2) quantity of weight gain varied among patients from 4.4 lbs. (2 kg) to 35.27 lbs. (16 kg) – for an average gain of 19.84 lbs. (9 kg); and (3) several cases (A, C, D, E, F) involved concurrent medication use – which might’ve also contributed to weight gain.
Authors of this report also documented the number of case reports compiled by the WHO (World Health Organization) and Eudravigilance. A total of 99 cases of weight gain in propranolol users were reported by the WHO and 39 cases of weight gain in propranolol users were reported by Eudravigilance.
Overall, the report by Lareb indicates that propranolol can cause weight gain as an adverse reaction. Although the exact means by which propranolol induces weight gain remains unclear, potential mechanisms culpable for the weight gain (that were proposed by authors) include: reductions in metabolic rate; decreased physical activity; inhibition of lipolysis; insulin resistance; and/or modulation of thermogenesis in brown adipose tissue.
2013: Preventive treatment in migraine and the new US guidelines.
Estemalik and Tepper published an article that reflected upon therapies for migraine prophylaxis and migraine treatment guidelines in the United States. In this article, authors mentioned that propranolol has been considered an effective migraine prophylactic since the United States migraine treatment guidelines published in 2000.
Following publication of the 2000 migraine treatment guidelines, another Class II study was conducted involving propranolol (80 mg/day). In the Class II study, it was discovered that propranolol (80 mg/day) was significantly more effective than a placebo – and equally as effective as cyproheptadine in the prevention of migraine.
Authors noted that propranolol can cause weight gain, sleep disturbances, and fatigue as side effects. However, according to authors, the incidence rates of weight gain and other side effects among propranolol users remained unclear at the time of this publication.
2008: Weight change associated with the use of migraine-preventive medications.
Taylor wrote an article reviewing the incidence of weight gain associated with migraine prophylactic medications, including propranolol. For the review, Taylor conducted a PubMed search for studies published between the dates 1970 and 2007 in which data was presented documenting weight changes (or lack thereof) among users of migraine prophylactics.
Although the double-blind, placebo-controlled trials were sought for the review –data from select open-label, retrospective, or prospective trials were incorporated in the results. Results of the review indicated that propranolol is associated with varying degrees of weight gain.
That said, weight gain seems to be more prevalent with amitriptyline and divalproex than propranolol. In any regard, this review supports the idea that propranolol can cause significant weight gain in a subset of users when administered as a migraine prophylactic.
2005: Weight variations in the prophylactic therapy of primary headaches: 6-month follow-up.
Maggioni, Ruffatti, Dainese, et al. recruited 367 individuals diagnosed with migraine (86% female, 14% male) and/or chronic tension-type headache to determine the prevalence of weight gain as a side effect of prophylactic therapy. Participants were assigned to receive: amitriptyline (20-40 mg); pizotifen (1 mg); propranolol (80-160 mg); atenolol (50-100 mg); verapamil (160-240 mg); valproate (600 mg); gabapentin (900-1200); or a placebo – for a 6-month duration.
A total of 89 patients (78% female, 22% male) underwent body weight assessments after 6 months of treatment. Of the 89 patients who completed 6 months of prophylactic therapy, it was noted that 13 were using propranolol (80-160 mg/day) as a standalone agent. Results indicated that, after 6 months of treatment, 8% of propranolol recipients (1 of 13) exhibited clinically relevant weight gain of ~13.22 lbs. (6 kg).
Researchers concluded that propranolol treatment can cause clinically relevant weight gain in a subset of users – when regularly administered for 6 months. This study supports the idea that moderate-term propranolol use can provoke substantial weight gain.
2004: Topiramate in migraine prophylaxis–results from a placebo-controlled trial with propranolol as an active control.
Diener, Tfelt-Hansen, Dahlöf, et al. presented the results of a randomized controlled trial in which topiramate and propranolol were evaluated for the prophylaxis of migraine. For the study, 179 individuals [with migraine] were assigned to receive propranolol (160 mg/day); 282 individuals were assigned to receive topiramate (100 mg/day or 200 mg/day); and 143 individuals were assigned to receive a placebo.
In addition to tracking the effectiveness of each medication for migraine prophylaxis, researchers recorded adverse effects. Results indicated that topiramate recipients exhibited significant weight loss during the core double-blind phase, whereas propranolol recipients exhibited significant weight gain (2.3%) compared to the placebo. This trial supports the idea that propranolol can cause weight gain.
2001: Use of beta-blockers in obesity hypertension: potential role of weight gain.
Pischon and Sharma published a report discussing the usage of beta-blockers among persons with a combination of obesity and hypertension. It was noted that beta blocker treatment can lead to weight gain in a subset of patients – and that (at the time of publication) this fact was relatively unknown to many medical doctors and researchers.
Authors of this report stated that the primary reason as to why weight gain wasn’t regarded as a side effect of beta blockers is related to the fact that most clinical trial data does not list weight gain as a side effect. However, in the subset of clinical trials documenting weight gain as a side effect, beta blockers were associated with a weight increase of 2.64 lbs. – a modest amount.
It was hypothesized (by Pischon and Sharma) that inhibition of beta receptors may reduce metabolic rate by approximately 10% and negatively modulate aspects of energy metabolism. Because there’s evidence that beta blockers can cause weight gain and disrupt energy metabolism, authors question whether they are a favorable first-line option among persons who are overweight or obese with comorbid hypertension – largely because they might promote additional weight gain (or interfere with weight loss efforts).
2000: A double blind controlled study of propranolol and cyproheptadine in migraine prophylaxis.
Rao, Das, Taraknath, et al. sought to examine the efficacy of propranolol, cyproheptadine, and their combination (propranolol plus cyproheptadine) for the prophylaxis of migraine. The researchers recruited a total of 259 patients (174 women, 85 men) with migraine and assigned them at random to one of 4 treatment groups: propranolol (40 mg, b.i.d.), cyproheptadine (2 mg, b.i.d.), combination (propranolol plus cyproheptadine), or placebo.
The treatments were administered for a 3-month span while effectiveness and adverse reactions were recorded. A total of 204 patients (134 women, 70 men) completed the study – while 55 patients dropped out. Although there were no major side effects associated with the treatments, 25 patients across all groups suffered from minor side effects – 11 of whom were receiving propranolol and 5 of whom were receiving propranolol plus cyproheptadine.
An analysis revealed that weight gain was one of the most common side effects reported by participants – along with drowsiness, sleep disturbances, fatigue, and dry mouth. However, because incidence rates of specific side effects associated with each treatment were not documented in the “full text” study report – it remains unknown as to whether weight gain was more (or less) prevalent among users of propranolol than cyproheptadine.
Nevertheless, 16 of 25 patients who experienced noteworthy side effects (one of which was weight gain) used propranolol – either as a standalone or with cyproheptadine. This considered, it’s reasonable to infer that propranolol treatment may induce weight gain over a 3-month duration.
1993: Weight gain induced by long-term propranolol treatment.
Martínez-Mir, Navarro-Badenes, Palop, et al. published a short case report describing weight gain in a patient due to long-term propranolol treatment. The case involved a 44-year-old female with a history of treatment-resistant migraine. The patient was prescribed propranolol (80 mg, b.i.d.) and responded well to the medication; it reduced the frequency and severity of attacks and enhanced mood.
That said, the patient reported significant weight gain from the medication. After just 4 months of propranolol use, the patient’s weight jumped from 134.48 lbs. (61 kg) to 145.5 lbs. (66 kg) – an 11.02 lb. increase. After 5 more months of propranolol treatment (9 months total), the patient’s weight increased by an additional 8.81 lbs. (4 kg).
In other words, the patient had gained a total of 19.84 lbs. in 9 months. Researchers noted that the patient’s body weight was 33.08% higher than what’s considered medically healthy for her height. Other causes for the patient’s weight gain (e.g. medical conditions, concurrent medication use, etc.) were ruled out – and it was concluded that propranolol may cause significant and rapid weight gain as an adverse reaction in a subset of users.
1992: Comparison of the efficacy and safety of flunarizine to propranolol in the prophylaxis of migraine.
Gawel, Kreeft, Nelson, et al. organized a study comparing propranolol and flunarizine as migraine prophylactics. The aim of the study was to determine whether one medication (propranolol or flunarizine) might be more effective and/or tolerable than the other.
A total of 94 patients (diagnosed with migraine) were recruited to participate in the study and assigned randomly to receive: propranolol (80 mg, b.i.d.) or flunarizine (10 mg, daily) – for a 4-month period. Results of the study indicated that both medications: substantially reduced migraine frequency and caused weight gain as a side effect.
1990: Long term propranolol treatment and changes in body weight after myocardial infarction.
Rössner, Taylor, Byington, et al. sought to evaluate the effect of long-term propranolol treatment on body weight. Researchers conducted a retrospective analysis of data extracted from a large-scale, randomized controlled clinical trial in which 3,837 patients were assigned to receive either propranolol or a placebo 5-21 days following an acute myocardial infarction – over a long-term (up to 40 months).
Body weights of all patients were recorded at annual doctor visits, which provided researchers with the data for their retrospective analysis. Results indicated that: after 1 year of treatment, 27% of propranolol recipients (450/1679) and 21% of placebo recipients (350/1648) exhibited weight gain in excess of 11 lbs.
After 1 year of treatment propranolol recipients exhibited greater average weight gain (~5.07 lbs.) compared to placebo recipients (~2.64 lbs.). The differences in body weights of propranolol and placebo recipients remained significant after 2 years and 3 years of treatment.
Following the second year of treatment, average weight gain from baseline was ~6.61 lbs. among propranolol users and 3.52 lbs. among placebo recipients. Researchers noted that greater weight gain among propranolol users (relative to placebo recipients) was not explained by confounding factors such as: diuretic use, physical activity, age, and/or sex.
It was concluded that long-term beta blockade yields significant and sustained weight gain. Moreover, it was stated that the average increase in body weight due to propranolol treatment was “moderate” – and for certain patients (with preexisting obesity), this may be problematic.
1990: A comparative trial of flunarizine and propranolol in the prevention of migraine.
Shimell, Fritz, and Levien organized a study in which the efficacy and tolerability of propranolol and flunarizine were compared in the prophylaxis of migraine. A total of 58 patients with migraine were recruited to participate in this 4-month double-blind trial and assigned to receive: propranolol 3 times per day at 60 mg (29 patients) OR flunarizine (28 patients); one patient withdrew from the study.
Incidence rates of side effects associated with each medication were documented throughout the 4-month treatment period. Among propranolol users, the most common side effects included: nightmares (6); tiredness (8); irritability (3); and weight gain (4).
Although more patients gained weight with flunarizine (9) than propranolol (4), this study supports the idea that propranolol can cause weight gain in a subset of users when administered regularly over a moderate duration (4 months) for migraine prophylaxis. Statistically speaking, 13.79% of propranolol users experienced significant weight gain in this study.
1988: Effect of ibuprofen on blood pressure control by propranolol and bendrofluazide.
Davies, Rawlins, Busson investigated the effect of adjunct ibuprofen on blood pressure control in 2 groups of patients with hypertension (~66.6 years of age): 5 propranolol users (120-360 mg/day) vs. 5 bendrofluazide users (2.5-10 mg/day). Researchers conducted a 7-week trial with a double-blind, double-placebo, randomized crossover design to test the effect of ibuprofen plus propranolol and ibuprofen plus bendrofluazide.
Results indicated that there were no substantial differences in blood pressure between the two groups of patients. It was noted that significant weight gain occurred in the bendrofluazide users, likely due to increased fluid retention (rather than body fat accumulation).
Nevertheless, one patient of the 5 receiving propranolol (20%) exhibited significant weight gain. Although the study was extremely small-scale and limited to middle-aged patients with hypertension, it provides evidence to support the idea that a subset of propranolol users may experience weight gain as a side effect.
1980: Propranolol dynamics in thyrotoxicosis.
Feely, Stevenson, and Crooks conducted a study in which 25 patients with thyrotoxicosis (too much thyroid hormone) underwent treatment with propranolol (160 mg/day) for 1-2 weeks. Patient responses to propranolol varied among patients, however, the medication caused a significant reduction in heart rate while seated, in the supine position, and during exercise.
Treatment with propranolol led to marked reductions in serum T3 (triiodothyronine) and plasma propranolol levels positively correlated with these reductions. In the group of 25 patients, thyrotoxicosis-induced weight loss was counteracted with propranolol – and weight gain was directly linked to elevations in plasma propranolol.
The results of this study support the idea that propranolol treatment could lead to healthy weight gain in patients with thyrotoxicosis by counteracting disease-related weight loss. Moreover, the ability of propranolol to counteract thyrotoxicosis-associated weight loss and stimulate weight gain – seems to be related to its plasma concentration.
1979: Propranolol, triiodothyronine, reverse triiodothyronine and thyroid disease.
Feely, Isles, Ratcliffe, et al. organized a study in which propranolol was administered to 16 patients with hyperthyroidism and 10 patients with hypothyroidism (as an adjunct to thyroxine). Researchers discovered that the administration of propranolol for 1-2 weeks to patients with hyperthyroidism substantially reduced serum T3 (triiodothyronine) concentrations.
Worth noting was the fact that serum T3 reductions in hyperthyroid patients directly correlated with steady state levels of propranolol. Hyperthyroidism-induced weight loss subsided in patients who exhibited significant reductions in serum T3 (attributable to propranolol therapy); this was likely followed by weight gain (due to reversal of the hyperthyroid state).
In patients with hypothyroidism, the combination of propranolol plus thyroxine increased T3 to a greater extent than standalone thyroxine therapy, which led to weight loss. Based on the results of this study, researchers concluded that propranolol modulates the peripheral conversion of thyroxine to T3 and rT3.
It’s possible that modulation of peripheral thyroid hormone conversion could be a mechanism by which propranolol induces weight gain in a subset of users – particularly persons with hyperthyroidism (or subclinical hyperthyroidism). This study supports the idea that propranolol treatment could lead to weight gain among individuals with hyperthyroidism.
Variables that influence Propranolol-mediated weight gain
There are numerous variables that could influence your likelihood of experiencing weight gain as a side effect of propranolol. Variables to consider as potential influencers of weight gain while taking propranolol include: duration of use; frequency of use; propranolol dosage; concurrent substance use; and other individual factors (medical conditions; age; genetics; lifestyle; body weight/composition; and prior substance use).
Duration of propranolol use
The duration over which you use propranolol may determine whether you gain weight and/or the amount of weight that you gain. Studies (of all sizes) and case reports support the idea that weight gain tends to be most significant within 6 to 12 months of initiating propranolol treatment.
However, it seems as though additional weight gain can occur after 1-year and 2-years of treatment. One large study noted an average weight gain of ~5.07 lbs. (within 1 year) and an additional average weight gain of ~1.54 lbs. within 2 years – resulting in a total gain of ~6.61 lbs.; additional weight gain was also reported between year 2 and year 3.
Considering the research findings, it’s reasonable to suspect that the longer you’ve been using propranolol, the more likely you’ll be to experience weight gain. Moreover, if you gained weight in the first year of treatment, you may experience additional weight gain (albeit a less significant amount) thereafter.
Frequency of propranolol administration
The frequency at which you administer propranolol could determine whether it causes weight gain. Trials and case reports in which weight gain was documented as a side effect reported daily propranolol administration (sometimes several times per day).
This considered, it’s reasonable to hypothesize that less frequent or infrequent propranolol use might be less likely to cause weight gain OR cause less significant weight gain – in comparison to daily administration. If you’re administering propranolol “as needed” (such as for performance anxiety) – your body won’t be under constant influence of the medication.
Assuming you skip days or weeks between dosing, your physiology should have time to revert back to homeostasis between doses – which should prevent weight gain from occurring. On the other hand, if you administer propranolol frequently (e.g. every day, several times per day) – likelihood of weight gain will increase (because you’ll constantly be under its influence).
The dosage of propranolol that you’re using could determine whether you gain weight during treatment – and if so, how many pounds you pack on. It is generally understood that larger doses of propranolol modulate aspects of physiology (e.g. metabolic rate, hormone levels, etc.) more significantly than smaller doses.
More specifically, a propranolol dose of 10 mg will not exert as strong of a beta receptor blockade (nor generate as prominent of downstream effects) as a propranolol dose of 80 mg. Due to greater physiologic modulation of larger propranolol doses, persons who are prone to weight gain from the medication may experience more significant weight gain at high doses compared to low doses.
Although weight gain has been documented in persons using just 10 mg of propranolol per day, most cases of weight gain involve doses between 80 mg and 160 mg per day. If you’ve gained a lot of weight on propranolol, your dosage might be partly to blame.
Concurrent substance use
Any concurrent substance(s) that you’re using with propranolol (including medications, supplements, over-the-counter drugs, etc.) could influence the amount of weight gain that you experience. Certain substances might counteract OR potentiate the physiologic mechanisms or effects by which propranolol induces weight gain.
For example, if you regularly use a psychostimulant with propranolol, the physiologic actions of the psychostimulant might negate the mechanisms by which propranolol would’ve caused weight gain (e.g. slowed metabolic rate, decreased exercise tolerance, etc.). In this case, although you might’ve gained weight on propranolol as a standalone, you don’t notice any weight gain (as a result of your psychostimulant).
Another example could involve the usage of a serotonergic antidepressant and/or antipsychotic with propranolol. Serotonergic antidepressants and/or antipsychotics might potentiate certain physiologic mechanisms by which propranolol causes weight gain (e.g. slowing of metabolic rate, decreased exercise tolerance, increased appetite) – leading to greater weight gain than you would’ve experienced with standalone propranolol.
Individual propranolol user
A variety of individual factors could also determine which propranolol users are likely to gain a significant amount of weight. Examples of these individual factors include: age, body weight/composition, genetics, lifestyle, preexisting medical conditions, and prior substance use.
- Age: Some research indicates that the age of a propranolol user might impact the degree of weight gain that he/she experiences during treatment. One large study reported that propranolol users under the age of 60 gained ~2.1 kg, whereas users over the age of 60 gained ~1.4 kg. It’s possible that younger adults gain more weight than middle-aged users and/or elderly users – or vice-versa.
- Body weight/composition: A person’s body weight and composition prior to taking propranolol might impact the degree of weight gain that is experienced during treatment. Someone who is overweight or obese might be prone to greater (or lesser) weight gain on propranolol than a normal-weight or underweight individual. It’s also possible that preexisting body composition (body fat, lean mass, etc.) might influence likelihood of weight change on propranolol.
- Genetics: Genes implicated in propranolol metabolism and/or encoding for pharmacologic targets of propranolol – could determine how someone reacts to the medication, as well as whether weight gain is likely to occur. It’s possible persons who gain weight on propranolol might express (or lack expression of) certain genes – compared to those who don’t gain weight.
- Lifestyle: It’s not farfetched to think that a propranolol user’s lifestyle could influence his/her likelihood of weight gain on the medication. Someone who diligently tracks calories (to prevent overeating) and maintains a consistent exercise regimen may be less prone to weight gain than a person who isn’t very health-conscious.
- Medical conditions: Preexisting medical conditions might increase risk of weight gain while taking propranolol. For example, someone with hyperthyroidism or an anxiety disorder might be underweight due to excessive thyroid hormone production or anxiety-related appetite suppression, respectively. Because propranolol might reverse the hyperthyroid or anxious symptoms – healthy weight gain may occur. (In these cases, weight gain while using propranolol would be considered favorable).
- Prior substance use: The use of substances (e.g. medications) before propranolol might influence whether you notice weight change while on propranolol. If you discontinue a medication just prior to propranolol, and that medication caused weight loss, then you may experience a “weight rebound” effect while using propranolol. In this case, some (or all) of your weight gain could be related to your body reverting back to homeostasis (and no longer receiving a medication that promotes weight loss).
Potential strategies to minimize Propranolol-related weight gain
Listed below are some potentially-useful strategies for preventing or minimizing weight gain while using propranolol. Prior to implementing any of these strategies, it is recommended to speak with a medical doctor to ensure that any strategies you use are safe (based on your present medical status). Moreover, you should know that the effectiveness of these strategies will likely vary among propranolol users; some users may find them ineffective.
- Use propranolol infrequently: One way to significantly reduce the likelihood of weight gain on propranolol is to administer it infrequently or “as needed” (i.e. PRN). By administering propranolol infrequently or “as needed” (rather than every single day), your physiology won’t constantly be under the complete influence of propranolol – and may have a chance to revert back to homeostasis between doses. For this reason, the medication will be significantly less likely to cause weight gain – than if you administered it frequently (e.g. daily, several times per day). Though some individuals may need to administer propranolol every day – others will not.
- Limit calories: A relatively simple way to prevent and/or limit the amount of weight that you gain while using propranolol is to limit your calorie intake. Assuming propranolol slows your resting metabolic rate slightly, adjusting your calorie intake to a lower amount (to compensate for the slower metabolism) should help you avert excessive weight gain on the medication. Even if you gain some unwanted weight, monitoring and consuming a set number of calories should prevent major body weight increases.
- Exercise: It is known that propranolol alters energy substrate use during exercise which reduces exercise tolerance. Furthermore, propranolol can cause fatigue as a side effect which might interfere with exercise intensity and/or endurance. Although it might be challenging to exercise while using propranolol, adhering to an exercise regimen comprised of aerobic and/or strength training should help you maintain a high metabolic rate and favorable body composition throughout treatment to prevent excessive weight gain.
- High protein, low fat: Some studies indicate that propranolol administration could reduce fat oxidation. Reduced fat oxidation makes it more difficult for the body to use fat as energy, which could lead to increases in body fat among persons consuming high-fat diets while taking propranolol. If you’re gaining fat while using propranolol, consider eating a high-protein, high-carbohydrate, low fat diet – as this should limit weight gain attributable to reduced fat oxidation.
- Lowest effective dose: Although weight gain has been documented in case reports among persons using low doses of propranolol (e.g. 10 mg/day), weight gain tends to be more common among individuals using higher doses of propranolol (80-160 mg/day). Because higher doses might cause more weight gain than lower doses, it’s recommended to use the “minimal effective dose” (or lowest dosage needed to control your symptoms) – if you’re trying to prevent weight gain.
- Discontinue medically-unnecessary substances: Many individuals who gain weight while using propranolol are administering concurrent substances with it. The administration of concurrent substances (e.g. medications, supplements, etc.) could be interacting with propranolol in a way that yields greater weight gain than standalone propranolol would. Additionally, it’s possible that concurrent substances are causing more weight gain than propranolol is. For this reason, you may want to discontinue all medically-unnecessary substances that you’re using with propranolol – and evaluate whether your weight improves.
- Add-on medication: If you need propranolol to treat a medical condition, but none of the above strategies are helpful in reducing or reversing its weight gain side effect – you may want to ask your doctor about adjunct medications to help counteract the weight gain. For example, if you’re using propranolol for migraine prophylaxis, and it seems to be effective (but you’re gaining weight), a doctor may recommend that you try adjunct topiramate to counteract the weight gain.
Note: If you’ve tried implementing the strategies listed above yet the significant and/or unwanted weight gain persists – you should discuss this with a medical doctor. A medical doctor might suggest that you undergo propranolol withdrawal and/or transition to a different medication (that’s less likely to induce weight gain) for symptom management.
Have you gained weight while using propranolol?
If you’ve used propranolol and experienced weight gain (or weight loss), share the amount of weight change that you experienced – in the comments below. Assuming you monitored your body weight and/or composition before and during propranolol treatment, mention: how much weight gain (or loss) you noticed; how quickly it took for you to notice the weight change; and how your body composition changed (e.g. increased body fat, loss of lean mass, etc.).
To help others get a better understanding of your propranolol usage, provide additional details such as: the medical condition for which you were prescribed propranolol; your dosage; regularity of use (e.g. once per day); total duration of use; and whether you use other medications along with it. Have you considered that some of your weight change on propranolol could be due to treatment of your medical condition and/or caused by concurrent substance use?
After reflecting upon your weight gain on propranolol, what do you believe were the specific ways in which the medication caused you to gain weight? (Hypothetical answers might include things like: hormonal alterations; appetite increase; fatigue (making it difficult to exercise); slowed metabolism; reversed my hyperthyroidism; etc.).
In summary, it seems as though significant weight gain (in excess of 5 lbs.) might occur in 8% to 27% of propranolol users within the first year of treatment. Although weight should eventually plateau (and stabilize) following the first year of propranolol use – not everyone will be satisfied with their new weight. If the weight you gained from propranolol is problematic and/or jeopardizes your health – discuss this with a medical doctor and consider alternative treatment options.