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L-Tyrosine Side Effects & Adverse Reactions (List)

Tyrosine is a non-essential amino acid that was discovered in 1846 by Justus von Liebig, a German chemist.  The word “tyrosine” is derived from the Greek term “tyros” – meaning “cheese.”  L-Tyrosine is commonly taken in the form of a dietary supplement to facilitate catecholamine synthesis.

Upon ingestion of L-tyrosine, the body metabolizes it into catecholamines including: dopamine, norepinephrine, and epinephrine.  These catecholamines are thought to modulate aspects of neurophysiological functioning such as: attention, cognition, energy, mood, memory, and vigilance.  Individuals with suboptimal catecholamine synthesis may experience prominent deficits in various aspects of cognitive performance.

While one solution to increase catecholamine synthesis is to eat foods high in tyrosine (and phenylalanine) such as chicken, fish, and turkey – not everyone wants to make dietary alterations.  A common method for increasing catecholamine synthesis is to regularly supplement with L-tyrosine.  Supplementation of L-tyrosine is a quick, potent, and established method for increasing concentrations of beneficial neurotransmitters and preserving cognitive function. (Read: L-Tyrosine Benefits).

Despite the convenience of popping an L-tyrosine supplement to promote catecholamine synthesis, supplementation may provoke unwanted side effects.  While most L-tyrosine side effects are considered mild, they may be severe for certain individuals – triggering anxiety, heart rate changes, and/or headaches.  It is important to understand these potential adverse reactions prior to supplementation with L-tyrosine.

Factors that influence L-Tyrosine side effects

It is important to realize that there are many factors that may influence the quantity and severity of side effects that you experience while taking L-tyrosine.  These factors include things like: dosage, individual factors (e.g. neurophysiology), interactions, duration of supplementation, frequency of administration, and the specific source of L-tyrosine utilized.

1. Dosage (500 mg to 2000 mg)

There is a lack of medical guidelines to follow for L-tyrosine dosing.  In many cases, dosing is subject to significant variation based on a person’s bodyweight.  Some protocols call for administration of 100-150 mg/kg (bodyweight) per day.  With bodyweight-based protocols, individuals with greater bodyweight end up taking more L-tyrosine than those who are lighter.

Certain sources recommend experimenting with 500 mg to 2000 mg of L-tyrosine per day.  To minimize the likelihood of side effects and adverse reactions, you’ll want to take the minimal effective dose.  In other words, start with a very small dosage and gradually titrate upwards until you feel a noticeable improvement.

By keeping the dosing as low as possible, your neurophysiology is less altered by the drug.  Less significant neurophysiological alterations are associated with fewer and less severe side effects.  If you need to take a high dose of L-tyrosine, beware that problematic side effects are likely to significantly increase.

2. Individual variation

Many side effects from L-tyrosine are subject to individual variation.  Two people could take the same dosage, yet one may attain significant therapeutic benefit without any noticeable side effects, while the other may experience headaches, nausea, and diarrhea.  For this reason, it is important to consider your neurophysiology, genetics, and bodyweight as potentially influencing side effects from L-tyrosine supplementation.

For example, individuals with a disorder called “phenylketonuria” (PKU) are unable to metabolize phenylalanine (a precursor to tyrosine) as a result of genetic polymorphisms.  To increase tyrosine levels, and ultimately catecholamine synthesis, these individuals need L-tyrosine supplements.  It should be suggested that polymorphisms of certain genes could influence side effects.

While companies like GeneSight can predict individual side effects and responses to drugs, it is unclear as to whether they will expand their database to include supplements like L-tyrosine.  In addition to genetics, a person’s neurophysiology (brain waves, neurochemistry, hormones, and arousal) may influence side effects associated with L-tyrosine supplementation.  Other individual factors such as bodyweight, stress level, diet, sleep, and lifestyle may also influence responses to L-tyrosine.

3. Interactions

It is important to consider the possibility that certain L-tyrosine side effects may result from interactions with alcohol, drugs (illicit or pharmaceutical), or supplements.  Many people take L-tyrosine along with certain medications and/or as part of a supplement “stack.”  Whenever an individual co-administers L-tyrosine with another substance, it is difficult to understand whether side effects are specifically from: the L-tyrosine, the other substance, or an interaction effect.

Prior to supplementing with L-tyrosine, it is important to discuss potential contraindications with a medical professional.  A few well-established L-tyrosine interactions include: MAOIs (Monoamine Oxidase Inhibitors), Thyroid hormone, and L-Dopa (Levodopa).  Using MAOIs with L-tyrosine could increase blood pressure to the point of causing a heart attack or stroke.

Administration of thyroid hormone with L-tyrosine can increase thyroid levels too high, and cause hyperthyroidism.  It is important to investigate all potential interactions prior to taking L-tyrosine with another substance.  Understand that many other L-tyrosine interactions are still unknown, making it difficult to predict side effects associated with co-administration.

4. Time Span + Frequency

Those that have taken L-tyrosine for a long-term may be more likely to experience side effects than someone taking it on a short-term.  Most sources suggest that L-tyrosine is safe to supplement for up to 3 months (90 days), but it is unknown as to whether side effects and/or adverse reactions are more likely following several months.  In addition to the duration over which a person has taken L-tyrosine, it is important to consider the frequency of administration.

Someone who takes L-tyrosine for a long-term, on an everyday daily basis (or multiple times per day) may be more likely to experience adverse reactions than someone who takes it for a short-term on an intermittent (“as needed”) basis.  It should be noted that most research suggests short-term safety of L-tyrosine, but long-term effects remain unknown, especially when taken on a frequent basis.

Certain individuals may be more likely to experience more side effects when they first start taking L-tyrosine as a result of temporary physiological adaptation to the supplement.  Others may find that they don’t experience any short-term side effects, but develop unwanted long-term effects from supplementation.  Generally, tolerance is established over frequent, long-term administration of L-tyrosine – leading a person to increase the dose, which ultimately increases side effects.

5. Source & Formulation of L-tyrosine

It is important to consider that the source of L-tyrosine may influence the side effects a person experiences.  Some people may find that a certain brand of L-tyrosine produces less side effects than another.  In addition to consideration of the L-tyrosine brand and sourcing, the specific formulation may factor into the manifestation of side effects.

For example, some people may prefer to take N-Acetyl L-Tyrosine for enhanced absorption.  This may allow them to take lower doses that are more efficiently metabolized by the body, leading to less noticeable side effects compared to an individual taking a standardized L-tyrosine supplement.  There are many formulations of L-tyrosine, some of which may reduce the likelihood of side effects.

L-Tyrosine Side Effects & Adverse Reactions (List)

Below is a list of possible side effects that a person may experience when supplementing with L-tyrosine.  Understand that the quantity and severity of side effects are likely to be influenced by the aforementioned factors.  Realize that most people will not experience every single side effect on this list and that side effects are largely subject to individual variation.

Most common side effects associated with L-tyrosine supplementation include: heart rate changes, headaches, stomach aches, and increased anxiety.  It is unknown as to whether long-term supplementation is safe.  If you develop any of these side effects, it is recommended to consult a medical professional.

  • Abnormal heart rate: Many people notice that their heart rate increases and/or becomes abnormal upon supplementation of L-tyrosine. This is due to the fact that L-tyrosine is converted into catecholamines, synthesizing stimulatory neurotransmitters.  In certain individuals, this increased CNS stimulation can result in heart rate abnormalities.
  • Agitation: Some people become increasingly agitated when they first start taking L-tyrosine. This may be due to the time of day in which it is taken, but could also be related to the dosage.  To decrease the likelihood of agitation, L-tyrosine should only be taken intermittently on an “as-needed” basis at a low dose.
  • Anxiety: While some people experience a counterintuitive decrease in anxiety from L-tyrosine, most people experience a mild increase. The increase in anxiety may result from increased catecholamine synthesis, promoting increased vigilance and heightened stimulation.  If anxiety becomes severe, decreasing the dosage and/or discontinuation may be advised.
  • Appetite changes: Some people notice that their appetite decreases when taking L-tyrosine. This decrease in appetite could be temporary and fueled by an increase in synthesis of catecholamines.  If catecholamine levels are suboptimal, L-tyrosine supplementation may increase their levels within a normal range, inducing a temporary reduction of appetite.
  • Blood pressure changes: Scientific research suggests that L-tyrosine is capable of increasing and/or decreasing blood pressure – based on the individual. Those with hypertension should be monitored for spikes in blood pressure following administration of L-tyrosine.  While L-tyrosine is more likely to increase blood pressure, it may decrease blood pressure in select individuals.
  • Chest pain: It has been reported that chest pain may occur when taking L-tyrosine. The chest pain experienced is generally mild and accompanied by shortness of breath and/or heart rate abnormalities.  It is important to realize that chest pain could be a sign of a serious adverse effect.  Consult a medical professional if L-tyrosine supplementation provokes chest pain.
  • Diarrhea: At higher doses of L-tyrosine, people are at increased risk of experiencing disaster pants a.k.a. diarrhea. Lower doses may cause an upset stomach, or gastrointestinal discomfort, but at higher doses, you may experience an unwanted excess of bowel movements.  This side effect can often be mitigated by reducing the dosage and/or temporary discontinuation.
  • Difficulty breathing: You may notice that you experience breathing difficulties following administration of L-tyrosine. These breathing difficulties may be triggered by increases in CNS stimulation associated with synthesis of stimulatory neurotransmitters.  Should you experience changes in respiratory function, seek immediate medical attention.
  • Dizziness: Many people report increases in dizziness when they first start taking L-tyrosine. The dizziness is generally mild or moderate, but may be more extreme among those ingesting high doses of L-tyrosine.  Dizziness generally subsides as the body adapts to the presence of L-tyrosine, but may also diminish with a dosage reduction.
  • Drowsiness: A counterintuitive reaction from L-tyrosine supplementation is drowsiness. Should you become drowsy, it is important to consider potential interaction effects and/or that your body may not respond well to L-tyrosine supplementation.  Drowsiness may diminish after a week of consistent supplementation and/or with reductions in dosing.
  • Fatigue: A side effect that some people experience while taking L-tyrosine is increased fatigue. The increase in fatigue is generally not extreme to the extent of sleepiness, but may be pronounced.  This is considered a counterintuitive reaction due to the fact that L-tyrosine is associated with increases in vigilance and energy.  Some people find that fatigue decreases as the body adapts to L-tyrosine, while others find altering the dosage helpful.
  • Headaches: One of the most common side effects from L-tyrosine supplementation is a headache. Most people experience mild or moderate headaches, which may be caused by increased synthesis of stimulatory neurotransmitters.  Should headaches become severe, it is important to consider reducing the dosage.  Further, realize that interactions and/or dehydration may exacerbate L-tyrosine-induced headaches.
  • Heartburn: In some cases, a person may experience indigestion accompanied by burning sensations in their chest when taking L-tyrosine. This is related to regurgitation of stomach acid back into the esophagus.  If you notice that this supplement is triggering heartburn, discontinue and/or lower the dosage and determine whether the heartburn subsides.
  • Heart palpitations: If you notice that your heart becomes increasingly strong, rapid, or irregular after L-tyrosine supplementation, it may not be a coincidence. Increases in concentrations of stimulatory neurotransmitters and heightened arousal could promote heart palpitations.  These palpitations may be uncomfortable and lead to increases in anxiety.
  • Insomnia: L-tyrosine is capable of triggering insomnia, or inability to fall asleep. Others may find that L-tyrosine increases the likelihood of broken sleep and decreases sleep quality.  By reducing the dosage and taking L-tyrosine in the morning (rather than afternoon or night), insomnia may be less likely to occur.
  • Irritability: It is known that L-tyrosine can increase catecholamine synthesis, which in turn can increase CNS activation (arousal), and provoke feelings of irritability. Those that experience irritability from L-tyrosine may be more prone to agitation, restlessness, and nervousness.  In some cases, the irritability diminishes as the neurophysiology adapts to supplementation.
  • Joint pain: A relatively odd side effect associated with L-tyrosine supplementation is joint pain. The joint pain associated with supplementation of L-tyrosine is generally mild, but may be exacerbated by increased doses.  To reduce the likelihood of joint pain, consider lowering your dosage and/or temporary discontinuation.
  • Nausea: Another unfavorable side effect associated with L-tyrosine is that of nausea. The nausea associated with L-tyrosine is generally mild, but may become increasingly severe with higher doses.  Some individuals have reported that the nausea from L-tyrosine supplementation became so extreme that they nearly vomited.
  • Nervousness: As a result of increased catecholamine production, many people find L-tyrosine causes nervousness. This heightened nervousness is generally mild or moderate, but may be troubling for individuals with a history of anxiety.  Nervousness may subside as the body adjusts to accommodate increases in catecholamine reserves, but not in all cases.
  • Restlessness: Since L-tyrosine facilitates the production of dopamine, norepinephrine, and epinephrine – increased CNS stimulation is often noted. This increase in CNS stimulation may elicit feelings of restlessness.  A person may feel unsettled, nervous, and have a difficult time sitting still with an increased need to move around or pace.
  • Skin rashes: Certain individuals may be unable to tolerate L-tyrosine as evidenced by skin rashes. The rash may be concentrated in a specific area or widespread throughout the body.  It may be itchy as a result of “hives” and characterized by swelling.  Development of a rash may be related to dosage, interactions, source of L-tyrosine, or individual intolerability.
  • Stomach aches: It is known that higher doses of L-tyrosine can cause gastrointestinal discomfort, ultimately contributing to stomach aches and pains. Those that experience stomach aches may find that a dosage reduction lessens the severity of the aches.  Most stomach aches experienced are mild, but may increase in severity with high doses.
  • Thyroid dysfunction: It is possible to end up with hyperthyroidism (overactive thyroid) from supplementing with L-tyrosine. This is due to the fact that L-tyrosine can stimulate the production of thyroid hormones.  If you have a history of hyperthyroidism or are taking thyroid medications, it is important to avoid supplementation of L-tyrosine.
  • Weight loss: Some people end up losing weight when they first start taking L-tyrosine. There is some evidence to suggest that L-tyrosine can improve neurophysiological function associated with dietary restriction, ultimately provoking weight loss.  In addition, some people find that L-tyrosine suppresses their appetite while simultaneously provides more energy to hit the gym.

L-Tyrosine: Weighing the Pros (Benefits) & Cons (Side Effects)

It is important to always weigh the therapeutic benefits with the side effects when taking any supplement, including L-tyrosine.  Certain individuals may find that the therapeutic benefits for cognitive function significantly outweigh any side effects.  For example, assuming you take L-tyrosine and your focus significantly improves without any side effects; in this case the benefits clearly outweigh the side effects (because you don’t have any).

Another individual may find that taking L-tyrosine triggers severe anxiety and heart palpitations.  This person may not derive (or notice) any significant therapeutic benefit from L-tyrosine supplementation.  In this case, it is relatively obvious that the side effects outweigh the benefits (because none were experienced).

It gets trickier to determine whether the benefits outweigh the side effects when a person experiences noticeable cognitive enhancement coupled with diarrhea and nausea.  Ultimately it is up to you to assess whether the benefits are substantial enough to proceed with supplementation despite the disconcerting side effects.  After a few weeks of supplementation and dosage tweaking, most people will be able to determine whether L-tyrosine is a good fit for their individual biochemistry.

Have you noticed any significant L-Tyrosine side effects?

If you’ve taken L-tyrosine, feel free to share a comment mentioning whether you’ve experienced any significant side effects and/or adverse reactions.  To help others get a better understanding of your situation, mention the dosage you were taking, the time span over which you had been taking L-tyrosine, and the frequency of administration.  Also provide more specifics such as the brand and formulation of L-tyrosine, whether you took it with other drugs (or supplements), and the time of day you took it.

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{ 31 comments… add one }
  • mahmoud August 26, 2018, 11:36 pm

    Does supplementing with L-Tyrosine could lead to dependence? As I understand L tyrosine is made by the body, so could taking L-Tyrosine as a supplement lead to a negative feedback loop in the body where it produces less tyrosine – causing the body to depend on external sources and stop making its own?

  • Christopher D. Herrington May 25, 2018, 2:45 pm

    After reading through these stories, I think most people are taking way too much. Tyrosine does not create dopamine directly when taken as a supplement…it acts as a buffer… so, what is needed, IMHO, is a therapeutic dose of about 75-100 mg.

    Cut tablets in 1/8’s if needed… use the smallest amount…and increase until the range is noticed… seriously…it may be helpful to work your way into it.

    Secondly, a week or two… not years… to get back on your emotional feet… you bought a Ferarri, don’t burn rubber on the way out of the parking lot going 220 mph. Enjoy the ride.

  • Maria May 18, 2018, 5:30 pm

    L-Tyrosine was in several different combo supplements I was taking for about a year. Then, all of the sudden, I started to get almost every symptom on this article of too much: anxiety, increased heart rate, insomnia, diarrhea, agitation, blood pressure changes, chest pain, joint pain, difficulty breathing, heartburn, etc.

    I thought I was dying! But then I realized my levels of this are probably optimal now since I’ve been taking it for a year. I also realized this is a popular amino acid in those collagen drink mixes that are very popular right now (as is the amino acid that turns into tyrosine. Can’t remember the name right now!).

    So I was taking collagen peptides with this in it, in addition to taking it in a thyroid support formula (had HIGH levels of L-Tyrosine) and an immune strengthening formula and I think it is just way too much.

    Going to reduce now after seeing these symptoms… definitely! So glad to learn this was the cause of those symptoms and that I’m not going crazy.

  • Imran May 12, 2018, 12:35 pm

    I only took L-Tyrosine 500mg for 3 days but since then I am having pain in all my joints. I am no longer using it but the joint pain is still there. I totally don’t understand the connection and am quite worried if this could be a long term issue.

    Now I am going to consult my doctor. I recommend everyone to be very careful before taking any food supplement. There are side effects and these are available without any prescription.

    • Christopher D. Herrington May 25, 2018, 2:27 pm

      Tyrosine is often sold in tablets that have to be broken up. My tabs are 1000 mg, and so I cut them up into way smaller chunks… 6 or even 8 chunks.

      I lined them up and took the smallest one first day… taking increasingly larger chunks, but none over 200… 1000 would have knocked me out. 75 to 100 is about right…

  • Michael NW December 28, 2017, 12:45 am

    Hi. I take N acetyl Tyrosine 300mg and 500mg of L-Phenylalanine feom time to time. Some times every morning. Now and then I feel stimulated. I have been taking Curcumin with it which apparently helps to prevent dopamine degradation. Anyway, lately when I have taken tyrosine and l-phenylalanine I get energy surges.

    Sometimes it feels good but other times it feels that it completely whacks my CNS and I have elevated heartbeat, high blood pressure, no appetite although hungry and a bit of nausea. Today was really bad. I have been taking these on/off for about 2 years. I think my dopamine/norepinephrine levels may be normal and I don’t need more.

    I have Pyroluria and my ND said she doesn’t use tyrosine as part of the pyroluria protocol will help make the dopamine needed from food. I do have a sensitive CNS and some adrenal fatigue in the past. So I’m going to go off tyrosine and l-phenylalanine and see how I do. Michael

  • Bryon Tolle March 27, 2017, 5:34 am

    I hope my comments are helpful… the pain and life-limiting symptoms so many endure truthfully hurts my soul. So, please take my comments in the most positive way, knowing that I understand there are some making it just one day at a time. Maybe my efforts can be used as a baseline for others. I take N acetyl tyrosine as part of my own designed program.

    I have my own small issues compared to the challenges many have… no real medical problems, but more THE quality of life has significantly diminished. I don’t even have a doctor. No PTSD, No ADHD-PI, no overpowering anxieties – but I still see tyrosine as a very worthwhile supplement. I have been taking about 300mg once a day for about a week. I upped it today to 500mg and got quite dizzy a few times and a foggy mind… no big deal and I will go back to 300mg.

    Remember I am taking N.A.L.T. which is much more potent than just tyrosine. I am taking approx 25 different supplements daily and have researched each one intensively. For years I have been ordering my own blood lab tests for evaluations. Here is my point… most everything taken in large doses makes people feel better for a short time and then they are worse off than before.

    This is not an effective way to do it and using tyrosine as a power booster or mood enhancer will make things worse! There are no “single fix” supplements out there. For example, one person mentioned high use of Alcohol for a long time… that person’s liver is in no shape to handle the metabolites and oxidants that occur with high mg supplementations. FIX/STRENGTHEN THE LIVER FIRST.

    I know everything hurts but you must take more time investigating nutrients before taking them. For example did you know that tyrosine is a precursor for some estrogens…which increased, can cause many of the symptoms users mentioned. NALT is also a cortisol regulator… how are your adrenal’s cortisol and DHEA levels doing? Are they exhausted/fatigued?

    If so you could get an upper from the tyrosine and then shortly crash even worse because your adrenals can’t handle it. How about your thyroid… tyrosine helps make thyroid hormones which will spark the energy for a bit and then crash you HARD because the exhausted adrenals cannot handle the short term thyroid energy because everything works synergistically “together” at the same time.

    A single link breaks and the whole chain breaks. I worked on my thyroid to no avail and had no improvements until I found that when the adrenals are exhausted, the thyroid tries to pick up the slack making it look like a thyroid problem when it’s not. This is why so many people are on thyroid meds when they don’t really need to be and most don’t even improve with it.

    I now am doing my own adrenal support program and it is amazing. The liver, pancreas, adrenals, thyroid, kidneys, and gut flora must all be in the best possible working order… so work on them foremost. I know that is simple to say and very hard for some to do… and I know we all would love a quick fix… it’s just not there. Tyrosine produces more thyroid hormones… low on iodine? Low on iron?

    You’re making things worse for yourself plus missing out on a very beneficial nutrient such as tyrosine that can have such great results. My comments are coming from years of efforts to get to this point of self-realization and I hope people understand the depth of my comments and my heart of understanding. Best regards.

    • Marti May 9, 2017, 2:37 pm

      I appreciate your information, Bryon, as well as the article above. I tend to be hypoglycemic and pre-diabetic with varying amounts of depression. I’m almost 60 and I don’t take meds. It’s a battle to stay away from sugar and drink more water. I was taking Swanson’s Thyroid Blend with 300 mg of L-tyrosine.

      I had dizziness, anxiety, mild chest pain and possibly heart palpitations. I thought it was from life circumstances but now I can see it’s happened when I’ve taken the supplement. I can’t take a half-dose because it’s in sealed capsules. You’ve convinced me of implementing the detox method recommended by The Truth About Cancer (I don’t have cancer), which includes detoxing the gut, urinary tract, lymphatic system and liver.

      I think in that order. I know the first two are right. I agree that the adrenals need to be fixed, but I didn’t know that should happen before the thyroid. Thanks for your common-sense view, Bryon, and for a more in-depth article than other sites, Mental Health Daily — the other sites I read did not include dizziness.

      Nutritional research, eating real food and taking a well-rounded regiment of supplements geared to your own body’s needs are the way to approach wellness, rather than a hit-or-miss approach hoping for quick results from “miracle” nutrients.

      • Hope October 4, 2018, 4:39 am

        Using the powdered form. Use smallest dose possible… I’m going to take it three times a week, and only when I need it. This may do the trick… I am also diabetic and maintain on diet only. No meds. Good luck.

  • Louise Gadoury December 16, 2016, 1:11 am

    I took a whole bottle of 750mg once per day in the mornings for ADHD and it helped with energy and mood, but especially focus. It took me too long to figure out what has been happening with the latest 500mg dosing from now. I’m completely E X H A U S T E D. Couldn’t even function at work. Total waste of my time, man. They should report how volatile the effects are, from what I read here, it’s too all over the place to take with any certainty.

  • Me November 23, 2016, 5:19 am

    At first I thought it was awesome. It made me feel like running and lifting heavy weights. Then I noticed I’ve been angry in a way that’s really not me. I’m discontinuing for now. I would try it again for a race or athletic event but not continually.

  • Adamantix November 17, 2016, 9:55 am

    I’ve started taking L-Tyrosine a few weeks ago, 500 mg everyday, somedays I took 1000 mg in the morning, on an empty stomach. Also I took 5 HTP (50 mg), B Complex, Omega 3-6-9 and a hair supplement. Thing is I’ve noticed my hair started falling, getting thinner which is so scary. Also I gained weight. I’m not thin and I don’t have the most healthy diet, but it worries me because the tyrosine and 5HTP should actually help me lose weight, not gain it. Could L-tyrosine cause these symptoms?

  • Robin November 15, 2016, 6:08 pm

    I took l-tyrosine for over two weeks and it was working beautifully for low energy due to ADHD-PI. Now suddenly it seems to be making sleepy and giving me a little brain fog, neither of which I need again. :-) So I’m going to try lowering my dosage and see what happens.

  • Patti November 14, 2016, 9:56 pm

    I took 500 mg of tyrosine, Natures capsules, dissolved powder under tongue daily for about 7 days. Then I noticed my left corner of eye getting very red, itchy and scaly, and started to half swell. Went off it 2 days ago, how long will side effect last and how do I treat this, besides eye cream and petroleum. My ears are itchy too, been using Vit E and petroleum. Thank you for any help.

  • Nicole November 4, 2016, 11:56 pm

    Hi I’ve been taking 500mg morning and afternoon of tyrosine (brand now) and I found it fine the first couple of days but after a week I’m feeling overmedicated! Started taking it to help brain fog and encourage weight loss and I have an under active thyroid. I’d read that it helps thyroid function! In terms of side effects, anxiety, irritability, some nausea and gastric issues.

    I also feel restless and warmer, small rash on my front appeared after 5 days and on my back which I felt was from exercise but reading this no!! I noticed it has suppressed my appetite A LOT and I feel slimmer if that makes sense just after a week. Looser bowels definitely noted but more scary I found I was hyper alert and had racing thoughts.

    This will probably all subside if I drop right down to 50mg-100mg a day or every other which is a lot less than the stated dose of up to 3 x 500mg daily!!! The side effects have put me off taking it anymore… I’ll see how I feel in a few days of not taking it.

  • Vicki Ward October 29, 2016, 6:54 pm

    I have been taking a combination of 500 mg L-Tyrosine and 375 mg of DL-Phenylalanine three times a day per my nutritionist after getting off of SSRI’s for over 20 years. I have PTSD, general anxiety disorder and a history of depression. I thought giving this a go would be a good idea. Now after 3 months, my anxiety level is off the charts and my hyper-vigilance is non-stop.

    I talked to the provider who told me to cut the dosage in half. I am feeling a bit calmer, but still feel like I have a short circuit to the panic button, still. I am also on 75mcg of Levothyroxine and had no idea that a person should not take the Tyrosine while on this medication. No wonder I am so amped up!!! This morning I took my last dose, I think.

    My energy level is definitely up, fatigue down, etc. but the anxiety, the lack of sound sleep and headaches just seem too much. All this time, I’ve been thinking it’s me just not coping well. Has anyone else with PTSD seen any benefits? I am really puzzled after reading your article and the comments why I was put on such a high dosage.

  • Pamela October 29, 2016, 2:54 pm

    I have been taking L tyrosine 500 mg daily for about three years now. I find it helps with mental acuity. This is the reason I started taking it. I have no adverse side effects, but recently my joints have been hurting. I have read that L tyrosine could cause joint issues after prolonged use. I don’t know if this is the culprit or if it is something else. Has anyone else had a similar experience?

  • Bridgett October 28, 2016, 10:43 am

    I went to a Homeopathic Specialist for a skin rash and she gave me a mixture of stuff (to combat bacteria) and Tyrosine (500 mg, every other day) a week ago. I felt nausea at first (it’s gone now) and I constantly feel full. I am overweight, so I am not unhappy with that. I am supposed to stay on this regiment for a month and I will, pending no serious side effects. I found all of these comments very useful, as she never explained much to me. The proof will be if it clears up my rash.

    • Patti November 15, 2016, 7:02 pm

      Watch out, instead of clearing up a rash, it could cause one.

  • adp October 22, 2016, 4:46 pm

    I have been trialling L-tyrosine to deal with Parkinson’s-like tremors that the neurologist feels are due to ‘your brain being stressed from being in pain so long’. The tremors are not expected and thus are alarming to me. I am dealing with a 4 yr non relenting Rt side headache w/pain to face/eye/ear and well.

    I always have rt head pain [3-6/10 normally] but shortly after dosing of Tyrosine the h/a becomes very severe and lasts many hours. I’ve trialled to make sure it’s the Tyrosine and it definitely is. BUT… the tremors subside… so hmmm… how to balance costs/benefits? Just a heads up for anyone else who might be experiencing this.

    I DO notice better thought processing and acuity, reduced tremors and better vision to rt eye, but the head pain flares are pretty nasty…

  • Sandra September 30, 2016, 9:04 pm

    Taking L-tyrosine helped my depression. Now after two weeks I have fatigue, at first I had great energy. I take 500 mlg every other day.

  • Robert August 6, 2016, 6:43 pm

    I’ve been taking Swanson Ajipure 500 mg, one a day, for about 4 months now. Since about that time, I’ve had a rash on my back, rather hives-like. I never thought about the L-Tyrosine till now. And come to think of it, I have on occasion noticed a little mild chest pain and some palpitations. This was surprising as I am in top physical condition although I am 70.

    I am going to stop taking this supplement and see if the rash clears up. I had been blaming it on strawberries since we’ve been eating them steadily since about that time as well. I’ve never had a strawberry rash before though. I realize though that allergies can crop up anytime.

  • Tonya Ferguson June 10, 2016, 2:05 pm

    I have taken L tyrosine 500 mg in the past not very often, like since 2012 I’ve taken 2 or 3 bottles – but not all at one time, spread out. I never had any side effects or problems. I’ve taken the brand Now, not any other brand, just recently I bought the brand Swanson 500 mg. I just took one and got a severe major headache. I didn’t take any more but the headache came back before I went to bed.

    When I got up the next morning I was taking tylenol for it. The headaches got less severe each time… on the third day I got a very light headache. I’m scared to take anymore, and I’m not going to. I don’t know if it was the brand or not. Maybe I should go back to the Now brand. I don’t know.

    But I don’t want no more headaches like that – it was very very bad. I have never had a headache that bad before, I’ve had migraines that weren’t that bad. I’m scared to take any L tyrosine at all.

  • Ken March 6, 2016, 2:42 am

    I found this web site after suspecting L-Tyrosine induced diarrhea. The recommended dosage of quarter teaspoon powder (NZ Longevity Foundation) three times a day on an empty stomach (before meals) caused diarrhea. I stopped taking it and my bowels returned to normal. Re-started the supplement after 4 days normal movement. With 2 doses morning and pre-noon, I had sudden diarrhea 2hrs after the second dose. I am stopping it for now.

    It may be I need to reduce the dose to just a single quarter teaspoon a day or less. Heart rate seems somewhat elevated; blood pressure possibly lowered. I was recommended L-Tyrosine after a hair analysis revealed a deficiency in tyrosine along with cystine (not cysteine, which was normal). I have had problems with mood disorders particular in the winter months.

    I have been aware for many years that I am particular sensitive to the absence of sunlight, which is significant during Auckland winters (more so than in Toronto winters). I will try out Tyrosine in winter to see if it does improve “seasonal affective disorder”. I will report back.

  • Mimi January 27, 2016, 10:09 am

    A doctor suggested L-Tyrosine based on tests showing I lacked enough. My reaction was to clean without being able to stop. When I called her, she said that a reaction was not possible, as it is a natural supplement and no one in 16 years of practice had a reaction. So, I called the manufacturer and he said “rarely” someone has my reaction. He spoke to a nurse who was up outside of her Connecticut house, painting at 11PM and he told her to come down and come inside!

    He sent me GABA which felt like I would say a ‘downer’. Even cutting the dose doesn’t work for me. I literally put fork tongs in a glass of water and still have a reaction. I tried asking another doctor who said I “can’t break things down”. Does anyone else have a similar problem and what did you do for treatment? Maybe that’s why I’m ‘allergic’ to lots of things, family allergies, etc.

    • Natural May 30, 2016, 7:57 pm

      What you relate from you doctor is nonsense. Being natural has nothing to do with whether you can react. Chances are, the tyrosine you’re taking is not “natural” in the usual sense of the word either. Most tyrosine is manufactured by genetically engineered bacteria.

      Again, that has nothing to do with whether you’ll react, but do keep this in mind when people talk about what’s “natural” and what isn’t. “I’ve never seen it in sixteen years of practice” is also a sign of a bad doctor. Your doctor should be looking at the pharmacological research literature, not thinking back, “Do I remember personally seeing this?”

      Unless, of course, your doctor’s an omniscient superhuman who has carefully observed everyone taking every drug back to the beginning of time. At first sight, it sounds like you’re taking too much though, if your dose is already tiny, you’ll need to find out what pathway the tyrosine is acting on to interfere with normal activity.

    • Sally May 31, 2016, 9:49 pm

      Tyrosine makes me go into a cleaning frenzy too. I take it when I need to rally and get stuff done.

  • Claire December 11, 2015, 11:48 pm

    I found this website because I was experiencing severe nausea from the L-Tyrosine. Brand is “Now” 500 mg. This article was very helpful to me in figuring out what the heck was wrong with me. Now that you mention it, I also got the diarrhea, stomach pain, joint pain, anxiety, and irritableness. I just didn’t feel good but it definitely worked at giving me more energy and a mood rise, but sorry not worth it to feel this bad.

    I took one pill first thing in the morning and then another later that morning. Apparently too much. I have low thyroid and already take Prozac, so this was supposed to be a boost that has worked for me before, but really does not feel good this time, so I will stop taking it and find some other way to get more energy and mood brightener.

    • Sylvia September 29, 2016, 6:37 pm

      I don’t believe you are supposed to take it with Prozac or any other MAO inhibitor.

    • Colin March 11, 2017, 10:24 pm

      Have been taking 500mg capsule (Holland & Barrett) for 5 days along with Vit B complex, Ginka Bilboa and magnesium. Started taking because of long term depression and more recently worsening anxiety and chronic tiredness. Noticed that something had made a difference as my mood and energy levels have been far better – EXCEPT when I had alcohol a couple of days ago… I had the mother of all hangovers the next day – something I never experience despite excessive drinking in the past.

      The other significant side effect is aching joints – particularly around neck and shoulders. Am going to see how things pan out and then see my doctor in a few weeks to see what their view is. The main thing is that it’s made me aware of dopamine and the effects of low levels. I suspect that this has been my problem for many years (decades) and not serotonin deficiency. Any advice on all this gratefully received.

  • Lynn September 18, 2015, 1:41 pm

    I was hoping for some relief from low dopamine and tried L-Tyrosine and it caused an extreme hike in blood pressure.

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