Lexapro (Escitalopram) is a selective-serotonin reuptake inhibitor (SSRI) prescribed for the management of numerous neuropsychiatric conditions, including: major depressive disorder; generalized anxiety disorder; social anxiety disorder; obsessive-compulsive disorder; and panic disorder. Occasionally, Lexapro is sometimes prescribed off-label as an intervention for premenstrual syndrome (PMS) and seasonal affective disorder.
Although Lexapro is very similar to the drug Celexa in that it contains the same active stereoisomer, some patients claim to derive greater therapeutic benefit from Lexapro by comparison. Considering that escitalopram (the generic version of Lexapro) is inexpensive, only costing around $2 for a monthly prescription, it remains a heavily-prescribed antidepressant medication throughout the United States.
If you receive a prescription for Lexapro to manage a neuropsychiatric condition like major depressive disorder, you may be curious as to how long you’ll need to take the drug before it starts working or “kicks in.” Assuming you already Googled how long it should take for Lexapro to start working, it’s likely that you uncovered mixed reactions among users: some suggesting that the drug works right away (on Day 1) and others emphasizing that it takes weeks (6 to 8 weeks) – so who is right?
How long does it take for Lexapro to work or “kick in”?
It depends on the Lexapro user. In terms of exerting an effect within the central nervous system and altering neurotransmitter levels (particularly serotonin), Lexapro always starts working on the very first day of administration. In fact, Lexapro begins significantly inhibiting the reuptake of serotonin within just a few hours of ingesting the first dose.
Although Lexapro substantially modifies neurotransmission on the first day of treatment, this does not automatically mean that users will derive therapeutic benefit – or even notice that the medication is “working.” While a small percentage of Lexapro users may respond to the medication rapidly (e.g. on the very first day of treatment, or within several days of treatment initiation), most will not notice Lexapro working immediately.
It is most common for Lexapro users to notice the medication working (or alleviating medical symptoms) after several weeks of daily administration – usually between weeks 4 and 8 of treatment. Moreover, some individuals may require more than 8 weeks to notice that Lexapro has taken effect.
- Within days or first few weeks: A small percentage of Lexapro users may notice the medication working on the first day of treatment (e.g. within hours of administration) – or possibly within the first few days after starting treatment. Others may notice the medication kicking in within 1 to 3 weeks of treatment initiation.
- Within 8 weeks: It is estimated that over 80% of Lexapro users will report the medication working within 4 to 8 weeks of administration. If you don’t notice Lexapro working in the early days or weeks of treatment, understand that 8 weeks may be needed for the medication to take full effect.
- 8+ weeks: To attain therapeutic benefit and notice that the medication has “kicked in,” certain individuals might need to administer Lexapro for a duration exceeding 8 weeks. It is reasonable to speculate that a subset of persons who require more than 8 weeks to respond to Lexapro may have been under-dosed (taking too low of a dose) early in treatment – and might’ve needed a longer initial titration phase wherein the dose was gradually increased.
Keep in mind that Lexapro always is “working” (inhibiting the reuptake of serotonin) on the very first day of treatment. As a result, certain individuals will respond to Lexapro, or at least notice that they’re under its influence, within hours or the first few days of treatment. Among those who notice the effect of Lexapro right away, a subset of these individuals may also reap substantial therapeutic benefit – whereas others might notice its effect early in treatment yet derive insignificant therapeutic benefit until weeks have passed.
Despite the fact that Lexapro acts on neurochemical targets on the first day of treatment, not all users will be cognizant of its immediate effect. Certain users might not notice that they’re under the influence of Lexapro until they’ve been using it for 4 to 8 weeks. Others may experience a few side effects or subtle changes in conscious perception early in treatment, but no effect that could be considered therapeutic until week 8.
As Lexapro is administered for a longer duration (1 to 2 months) a greater number of physiologic adaptations occur throughout the central nervous system – compared to short-term administration. Specifically, it may take up to 8 weeks of treatment for 5-HT1A receptors to downregulate; BDNF to increase; and hippocampal neurogenesis to occur – each of which contribute to the antidepressant effect. Know that, although there’s individual variation in the onset of Lexapro’s action, most users will notice an effect within 8 weeks of treatment.
Note: It is understood that not everyone will notice Lexapro working. Certain Lexapro users may claim to feel no different while using the medication – than before using it, regardless of how long they take it. Others may end up feeling emotionally “numb” or more depressed than before Lexapro treatment – leading them to conclude that the medication never really “worked.” Though the medication always works or modifies neurochemistry, “working” does not always yield a therapeutic response.
Why Lexapro might work immediately or rapidly (Possible reasons)
It is known that, for a small percentage of users, Lexapro can start working immediately – or on the very first day of treatment. Others may notice that Lexapro works within several days – or even within a couple weeks of treatment. Persons who derive significant benefit from Lexapro in 1-3 days could be considered ultrarapid responders, those who respond to Lexapro in less than 2 weeks could be considered rapid responders, and individuals who respond to Lexapro in less than 4 weeks could be considered faster-than-average responders.
Below are possible reasons as to why Lexapro users may respond to the medication rapidly – or faster-than-average. Possible reasons as to why Lexapro may facilitate a rapid therapeutic effect in some users, include: the placebo response; its rapid action upon serotonin reuptake; and modulation of neural connectivity. Understand that there might be other explanations (in addition to the ones listed) as to why Lexapro may “kick in” faster than expected.
Placebo effect on Lexapro
If someone believes (with strong conviction) that Lexapro will work extremely well as a treatment for his/her particular medical condition, there’s a chance that this preexisting expectation may yield a placebo response immediately following treatment initiation. The placebo response is characterized by a marked shift in neurophysiologic activation – solely as a result of believing or expecting that the medication will alleviate symptoms.
For example, believing that Lexapro will effectively treat major depressive disorder may generate a placebo response – such that mood is noticeably enhanced within hours or days of treatment. Nevertheless, it is necessary to acknowledge that the degree of impact associated with a placebo response may vary in among rapid Lexapro responders.
In some cases, rapid responses to Lexapro may be fully attributable to the placebo response. In other cases, a combination of the placebo response plus serotonin reuptake inhibition (facilitated by Lexapro) may account for rapid responses. However, it is important to acknowledge that some Lexapro users may exhibit rapid responses with zero influence from a placebo effect.
Lexapro’s immediate SSRI action
Evidence suggests that, following its administration, Lexapro exerts a nearly-instantaneous neurochemical effect as a selective serotonin reuptake inhibitor (SSRI). More specifically, within a few hours of Lexapro ingestion, the chemical “escitalopram” will have undergone metabolism and distribution throughout the body. Escitalopram and its metabolites will be transported to the brain (across the blood-brain-barrier) and begin inhibiting the reuptake of serotonin ultimately increasing extracellular serotonin signaling.
In other words, in less than 24 hours after taking Lexapro, extracellular serotonin signaling will be markedly greater than baseline (pre-treatment). This substantial increase in extracellular serotonin signaling may be all that’s needed for someone to notice the medication taking effect or “working” on the first day of treatment. As a result, some individuals may report that the antidepressant or anxiolytic effect of Lexapro was noticed immediately after treatment initiation.
Lexapro modifies neural connections
In attempt to better understand how serotonergic antidepressants work, researchers conducted a study in which Lexapro was administered to participants who agreed to undergo neuroimaging scans (in the form of magnetic resonance imaging). Researchers discovered that a single dose of Lexapro (20 mg) significantly alters connectivity throughout the entire brain in 3-4 hours post-administration.
More specifically, researchers noted that Lexapro administration substantially decreased neural connectivity within a majority of cortical and subcortical regions, yet increased neural connectivity within the cerebellum and thalamus – all in under 4 hours. It was concluded that a single dose of Lexapro exerts rapid connectivity changes that encompass the entire brain.
Considering the fact that a single dose of Lexapro (20 mg) substantially modifies neural connectivity across the entire brain in less than 4 hours, it’s reasonable to suspect that this rapid connectivity alteration might yield a rapid treatment response in a subset of users. Perhaps it is changes in neural connectivity facilitated by Lexapro that might yield rapid responses experienced by a subset of users.
Why Lexapro may take longer than expected to start working
In a majority of users, Lexapro won’t facilitate noticeable therapeutic effects until it has been used for 4 to 8 weeks. Persons who respond to Lexapro in 4 to 8 weeks could be considered “normal” responders (due to the fact that this is when it’s most common to notice the medication working). That said, a small percentage of individuals may need even longer than 8 weeks for the medication to start working or reach peak therapeutic effect – these individuals could be considered “late” or “delayed” responders.
Listed below are some reasons as to why Lexapro may take longer than you expect to start working or “kick in.” Possible reasons as to why Lexapro can take 4 to 8+ weeks to manage your symptoms include: neurophysiologic adaptations that occur over weeks (such as 5-HT1A receptors and hippocampal neurogenesis) and/or adjustments in dosing (such as titrating the Lexapro dosage upwards from a subtherapeutic quantity). Realize that there might be additional explanations (other than those provided) as to why Lexapro may require a reasonable amount of time to start working.
Lexapro gradually downregulates 5-HT1A receptors
In certain Lexapro users, it is likely that 5-HT1A receptors need to decrease (i.e. downregulate) before a therapeutic effect occurs. Until 5-HT1A receptor downregulation occurs, a subset of users may not notice Lexapro working. Despite the fact that Lexapro increases extracellular serotonin signaling on the first day of administration, substantial 5-HT1A downregulation usually doesn’t occur until the medication has been used for several weeks.
The chief reason 5-HT1A receptors require time to downregulate is related to genomic signaling. When Lexapro inhibits the reuptake of serotonin in the brain, extracellular serotonin levels increase and stimulate 5-HT1A receptors to a greater extent than pre-treatment. The stimulation of 5-HT1A receptors by Lexapro should temporarily decrease the firing rates of serotonin-containing (i.e. serotonergic) neurons.
That said, as Lexapro continues interacting with 5-HT1A receptor sites over a longer-term (e.g. weeks), genes begin signaling for downregulation of 5-HT1A receptors. Once 5-HT1A receptors have downregulated, or decreased in population, serotonin-containing neurons become disinhibited whereby their firing rates dramatically increase. Increased firing rates of serotonergic neurons bolsters activation of postsynaptic serotonin receptors, possibly leading Lexapro users to derive therapeutic benefit – or report that the drug has begun working.
Another reason Lexapro may require more time than expected to start working is related to a delay in its induction of neuroplasticity. Though Lexapro induces neuroplastic changes within the brain by increasing BDNF and stimulating hippocampal neurogenesis and gliogenesis, these neuroplastic changes typically do not occur immediately.
For concentrations of BDNF to significantly increase and hippocampal neurogenesis and gliogenesis to occur – it is thought that Lexapro needs to be administered for a reasonable duration of 4 to 8 weeks. When Lexapro has been administered for 1 to 2 months, gene signaling will have occurred such that the medication will have facilitated the growth of new brain cells and tissue in the hippocampus.
The upregulation of BDNF coupled with hippocampal remodeling may be what contributes most substantially to the therapeutic effect derived from Lexapro – for a subset of users. Once the neuroplastic changes have occurred (e.g. hippocampal neurogenesis), it may seem as though the medication has finally “kicked in” or begun working.
Starting Lexapro dosage & titration rate
The specific dose of Lexapro that’s administered at the beginning of treatment and/or how quickly you titrate the dosage upwards might influence the onset of Lexapro’s action. A person initiating treatment a low dose of Lexapro (e.g. 5 mg per day) may undergo significantly less neurophysiologic modulation early in treatment – compared to a person who initiates treatment with a relatively high Lexapro dose (e.g. 20 mg per day).
Essentially, a 20 mg dose of Lexapro might exert 2-fold greater serotonin reuptake inhibition than a 10 mg dose. For this reason, someone taking 20 mg of Lexapro to start treatment may notice the medication working quicker than if he/she started with just 10 mg. Additionally, longer-term neurophysiologic adaptations to Lexapro such as 5-HT1A receptor downregulation and hippocampal neurogenesis may occur at a faster rate in high dose users.
Persons who begin Lexapro treatment with a lower dose might not notice the medication working right away due to the fact that the dose isn’t high enough to substantially modify neurochemistry and/or facilitate a therapeutic effect. A psychiatrist (or medical doctor) may recommend gradually titrating the dosage upwards (i.e. increasing the dose) for a new user such as by increasing from 10 mg to 20 mg after several weeks of treatment.
Following the titration phase or dosage increase, you might begin responding to Lexapro – or notice that it’s finally working. If you were instructed to slowly titrate the dosage in the first few weeks of treatment, it’s possible that you might’ve noticed a quicker effect with a higher starting dose. Nevertheless, know that low or subclinical dosing in the first few weeks of Lexapro treatment might be a reason as to why the medication can take a while to start working.
Variables that influence the onset of Lexapro’s action
There are a variety of influential variables that probably determine how long it takes for a Lexapro user to notice that the medication is working. Variables that probably determine the onset of Lexapro’s action include: Lexapro dosage; genetics of the user; prior substance (e.g. medication) use; whether substances are being used along with Lexapro; preexisting medical conditions; and self-awareness of the user.
A Lexapro user with high self-awareness who initiates treatment at a therapeutic dose (e.g. 420 mg) may report the medication working quicker than if he/she had low self-awareness and/or initiated treatment with a low dose (e.g. 5 mg). Moreover, someone with a history of antidepressant use might respond quicker to Lexapro than someone who’s never used antidepressants in the past. Read about the factors that could influence the rate of Lexapro’s action below.
Initial Lexapro dose
The initial dose of Lexapro that you use for treatment may determine how quickly the drug begins working. It is thought that, for most patients, the greater the dose of Lexapro that’s administered to start treatment – the faster the medication will “kick in” or facilitate a noticeable therapeutic effect.
This is because at higher doses, Lexapro provides more substantial serotonin reuptake inhibition than at lower doses. For example, a 20 mg dose of Lexapro should provide double the serotonin reuptake inhibition of a 10 mg dose such that extracellular serotonin signaling will greater – contributing to a more pronounced effect.
Additionally, it is thought that neurophysiologic adaptations that require time (such as 5-HT1A receptor downregulation and hippocampal remodeling) might occur at a quicker rate in persons who start treatment with a high dose – compared to a lower one. Though it often makes sense to start with a low Lexapro dose to give your body a chance to gradually adjust to its effect.
The low dose might take longer to start working due to lesser initial serotonin reuptake inhibition and slower induction of neurophysiologic adaptations necessary for therapeutic benefit. Eventually, as the low initial dose is increased within the upper therapeutic range, most users should notice Lexapro working.
Lexapro user genetics
The genetics of a Lexapro user might influence the rate at which it begins working – or facilitating a noticeable effect. When Lexapro is administered, it is known that CYP450 enzymes are implicated in its metabolism, namely: CYP2C19, CYP2D6, and CYP3A4. Assuming you have abnormal CYP2C19, CYP2D6, and/or CYP2C19 expression as a result of your genes, you might metabolize Lexapro differently (faster or slower) than average.
For example, someone expressing genes that yield poor CYP2C19 metabolism will end up with higher-than-average systemic concentrations of Lexapro. If a poor CYP2C19 metabolizer initiates treatment with a high dose of Lexapro, its effect may be pronounced earlier in treatment largely due to the fact that poor CYP2C19 metabolism yields more substantial exposure to the medication. (This is why it’s recommended to start at 50% of a normal Lexapro dose if your genetics indicate poor CYP2C19 metabolism).
On the other hand, someone expressing genes that yield rapid or ultrarapid CYP2C19 metabolism may be less likely to notice the medication working early in treatment. A rapid CYP2C19 metabolizer may need 8 weeks of treatment and dosage increases thereafter to derive a therapeutic benefit, largely due to the fact that rapid CYP2C19 metabolism reduces exposure to the medication. In fact, persons classified as CYP2C19 ultrarapid metabolizers may not even respond to Lexapro – or notice it working because systemic exposure is so minimal.
In addition to genes implicated in Lexapro pharmacokinetics, there may be genes that predict how effectively interacts with various neurochemical targets. For example, variants in the 5-HTTPLR gene may influence the amount of benefit someone derives from Lexapro, as well as how long it takes for the medication to start working.
- Source: https://www.pharmgkb.org/guideline/PA166127638
- Source: https://www.ncbi.nlm.nih.gov/pubmed/17146470/
Substance use prior to Lexapro
If you used substances prior to taking Lexapro, particularly substances that modulate neurotransmitters in the central nervous system, you may respond faster or slower than average to Lexapro. For example, if you recently used an SSRI for several weeks and then suddenly switched from the old SSRI to Lexapro – you might notice Lexapro working much quicker than if you had no prior history of SSRI use.
Why would Lexapro work quicker in someone who recently used an SSRI? Because if an SSRI was already used for a reasonable duration (e.g. 8 weeks), neurophysiologic adaptations will have likely occurred from SSRI treatment such as: 5-HT1A receptor downregulation and hippocampal remodeling. Due to these neurophysiologic adaptations already being present, Lexapro may begin working at a faster rate.
Moreover, if you have any history of using a substance that interacts with the neurotransmission of serotonin – or downstream neurochemical targets of Lexapro, this history may impact how long it’s going to take for Lexapro to provide a therapeutic effect. If you used substances that have opposing mechanisms of action to SSRIs, perhaps preexisting adaptations to those substances might delay the onset of Lexapro’s action.
That said, if you have no history of using neuropsychiatric substances before taking Lexapro, you should respond at a normal rate – due to lack of substance-mediated preexisting neurophysiologic adaptations. Additionally, even if you have a history of using neuropsychiatric substances prior to Lexapro, it’s no guarantee that you’ll respond at a different rate than average.
Concurrent substance use
If you’re taking substances along with Lexapro such as: pharmaceutical drugs; supplements; over-the-counter medications; illicit substances; etc. – these agents could influence the time it’ll take for Lexapro to kick in. Any concurrently-administered agents that overlap with the pharmacokinetic and/or pharmacodynamic profile of Lexapro might expedite or delay its onset of action.
Because Lexapro interacts with CYP450 enzymes such as: CYP2C19; CYP2D6; and CYP3A4 – any co-administered substance that also interacts with these enzymes could alter the rate at which Lexapro is metabolized. For example, concurrent administration of a medication that suppresses CYP2C19 function might result in much higher systemic concentrations of Lexapro than expected, leading to a faster onset of action (and likely more side effects).
Conversely, the concurrent administration of a medication that enhances CYP2C19 function might result in lower systemic concentrations of Lexapro than expected, leading to a slower onset of action (or possibly no noticeable effect). Additionally, certain medications may augment Lexapro pharmacodynamically such as by bolstering its neurochemical effect and/or induction of neurophysiologic adaptations (e.g. upregulation of BDNF).
Other medications might counteract the pharmacodynamics of Lexapro and reduce its neurochemical effect, ultimately delaying its onset of action – or preventing it from working. Reflect upon any substances that you’re using with Lexapro and realize that they might be a reason as to why its onset of action was quicker or slower than expected.
Preexisting medical conditions
A variety of preexisting medical conditions might influence how long it takes Lexapro to start working. For example, some individuals diagnosed with bipolar disorder may report a rapid onset of antidepressant action associated with Lexapro – such that the medication provokes mania (BP1) or hypomania (BP2). It is thought that certain neurochemical underpinnings of bipolar disorder may increase likelihood of rapid SSRI action.
Individuals with medical conditions like hepatic dysfunction or renal impairment might exhibit abnormal metabolism and clearance of Lexapro compared to healthy users. As a result of hepatic and/or renal abnormalities, Lexapro may start working quicker or later than expected. Moreover, individuals with forms of brain damage or neurodegeneration (such as in Alzheimer’s disease) might need more time than usual to respond to Lexapro due to impaired self-awareness and/or abnormal neurochemistry.
There are a couple user-specific factors that might influence how long it takes for Lexapro to exert a therapeutic effect. The specific way in which Lexapro is administered, as well as the level of a user’s self-awareness could impact how long the medication takes to start working.
How Lexapro is administered: How you choose to administer Lexapro might impact the rate at which it starts working. It’s reasonable to speculate that the time of day at which Lexapro is administered might alter its onset of action due to circadian interactions or “chronopharmacodynamics.”
Some individuals may report that Lexapro works quicker when consistently administered in the morning, others may report that the medication works faster when administered in the afternoon or evening, and others might report no impact of administration timing. That said, consistency of administration (e.g. taking Lexapro at approximately the same time each day) might influence how long it takes to work.
Although Lexapro can be administered with food or on an empty stomach, some individuals may notice the drug kicking in sooner if administered on an empty stomach (compared to after a meal) – or vice-versa. (Keep in mind that administration variables do not influence speed of Lexapro’s action in all users).
Self-awareness of the Lexapro user: Though how self-aware you are will not determine how quickly Lexapro starts working, it could determine how long it takes for you to notice its effect. If you have above-average self-awareness, it’s likely that you’ll be able to detect Lexapro facilitating an effect (or feel as though you’re under its influence) sooner than if you have lower-than-average self-awareness.
If you have limited self-awareness or intrinsic awareness, it might take a while for you to notice Lexapro working – even if it’s facilitating an effect. Engaging in self-reflection exercises while taking Lexapro (e.g. meditation) or taking time each day to assess how you’re feeling might help you detect its effect sooner than you otherwise would’ve.
How long did Lexapro take to “kick in” for me?
Not long. I noticed Lexapro “working” or facilitating an effect almost immediately. Although Lexapro failed to reduce my anxiety and depression (it actually exacerbated each of these symptoms), I noticed its effect on the very first day of treatment. I experienced a combination of: perceptual changes, altered thinking, and side effects within the first 24 hours of Lexapro administration.
Couldn’t this have been a nocebo effect? Yes, it’s possible that my response to Lexapro could’ve been a nocebo effect. However, it is important to consider that I initiated Lexapro treatment immediately after giving Celexa (Citalopram) an 8-week trial. In other words, there was no significant time gap between my trial of Celexa and initiating treatment with Lexapro, a medication with a nearly identical pharmacologic profile.
Due to the lack of time gap between treatments, my guess is that preexisting neurophysiologic adaptations from Celexa such as: 5-HT1A receptor downregulation and BDNF upregulation remained in place when I started Lexapro. For this reason, I think Lexapro was able to “kick in” immediately – simply picking up where the Celexa left off.
Lexapro contains the same active enantiomer as Celexa, meaning it theoretically should facilitate a very similar effect; this was consistent with my experience. My psychiatrist instructed me to use Lexapro for at least 8 weeks and to gradually titrate the dosage upwards (from 10 mg to 20 mg per day). Personally I didn’t notice much difference between Lexapro and Celexa – other than the fact that I felt slightly worse on Lexapro.
Over my 8+ week span of using Lexapro, I would continue experiencing a combination of: worsening depression and anxiety; restlessness; brain fog; depersonalization; and fatigue. In any regard, although I noticed Lexapro “working” on the first day of treatment, it never provided relief from my neuropsychiatric symptoms – eventually leading me to face Lexapro withdrawal symptoms.
How long did it take Lexapro to start working for you?
Assuming you’ve taken Lexapro in effort to treat a neuropsychiatric condition, how long did it take for you to notice the medication “working” after initiating treatment? (In other words, how long after starting treatment did it take for you to consciously notice that you were under the influence of Lexapro?)
How many days or weeks after starting Lexapro did it take for you to derive therapeutic benefit? (This is assuming you found the medication effective). To help others accurately understand your experience with Lexapro, provide some additional details in your comment such as: your starting Lexapro dose; whether you titrated the dose upwards (or increased it) after starting treatment; and whether you used other neuropsychiatric substances (e.g. other antidepressants) just before taking Lexapro.
Also mention things like: whether you took any substances with Lexapro (medications, supplements, etc.); preexisting medical conditions that might have affected its onset of action (e.g. liver impairment); and/or the specific medical condition(s) for which you were prescribed Lexapro. Consider noting: the time of day at which you take Lexapro; whether you’ve been consistent in your administration timing; and whether you take the medication with food or on an empty stomach.
Keep in mind that certain genetic polymorphisms associated with CYP450 enzymes, particularly CYP2C19, might influence how quickly Lexapro ends up working. If you know your CYP2C19, CYP2D6, and/or CYP3A4 status – document this in the comments. Finally, because self-awareness could impact your ability to detect Lexapro “working,” consider sharing your level of self-awareness (on a scale from 1 to 10 – assuming “10” is extremely high).