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Valerian Side Effects & Adverse Reactions (List)

Valerian is a dietary supplement that was first sold in the United States in 1994, but has been historically utilized as a medicinal herb since the days of ancient Greece and Rome.  It is understood to possess anxiolytic (anti-anxiety) and hypnotic (sleep-induction) properties and has been subject to investigation for the treatment of anxiety disorders and insomnia.  There is insufficient evidence to recommend valerian as a medical treatment for any condition, however, many anecdotal reports allude to its therapeutic potential.

In the United States, valerian is classified by the FDA as a “GRAS” (Generally Recognized As Safe) substance.  Valerian is thought to exert a therapeutic effect via multi-modal modulation of GABAergic neurotransmission.  Specifically, valerian is known to bind to GABAA receptors at the “beta subunit” (triggering a neurochemical cascade to decrease CNS activity) and prevent the enzymatic breakdown of GABA – thereby increasing GABA concentrations.

With such a mechanism of action, it is no surprise that individuals derive benefit from using valerian to enhance sleep or reduce stress.  Although valerian is a natural herb, it is important to realize that valerian may cause unwanted side effects or provoke adverse reactions.  If you’re using valerian and/or are considering it as a dietary supplement, it is important to be cognizant of its side effect profile.

Valerian Side Effects & Adverse Reactions (List)

Below is a list of side effects and adverse reactions associated with valerian.  Keep in mind that the severity and number of side effects experienced is subject to significant individual variation.  That said, the most common side effects reported among valerian users include: drowsiness, stomach aches, somnolence, and weird dreams.

Brain fog: A frequently reported side effect among valerian users is “brain fog” or clouded thinking.  Experiencing brain fog from valerian is common due to the fact that valerian decreases neurophysiological arousal below a homeostatic baseline.  Substances that decrease arousal and simultaneously modulate GABAergic activity can impair clarity of consciousness.  Do not be surprised if after taking valerian, you feel as if your brain is stuck in a foggy, hazy, or daydream-like state.

Perhaps the best way to combat the valerian-induced brain fog is via concomitant administration of a stimulatory agent.  However, it is necessary to consider that a stimulatory agent may offset the therapeutic effects derived from valerian.  Therefore, decreasing the dosage of valerian and/or taking it at a time of day in which brain fog isn’t considered problematic (e.g. at night) may be beneficial.

Cognitive deficits: Taking valerian, especially at high doses, can compromise cognitive performance.  Studies indicate that valerian impairs cognitive function among volunteers as evidenced by lower scores on a Stroop task.  Many users believe that valerian may interfere with aspects of cognition such as: attention, critical thinking, problem solving, planning, organization, and memorization.

Since valerian has a similar mechanism to benzodiazepines (via binding to a subunit of the GABAA receptor and hyperpolarizing the neuron), and benzos are associated with inability to encode memories and learn new information, it may be that valerian is comparably detrimental to cognition.  That said, cognitive deficits associated with valerian are likely mild (compared to benzos) due to the fact that it is less potent.  If you’ve experienced cognitive deficits from valerian supplementation, it may be necessary to revise your dosage, dosing schedule, and/or avoid using it altogether during cognitively-demanding occupational tasks or schoolwork.

Depression: Since valerian is known to decrease neurophysiological arousal, and reduced neurophysiological arousal is associated with depression, it’s no surprise that some users experience depression as a side effect.  A lack of stimulation and energy may lead to decreased production of catecholamines (e.g. dopamine and norepinephrine) and/or neuroelectrical changes (e.g. reduced beta waves), which could prompt a melancholic mood and/or negative outlook.  If you have a history of depression, it is important to be cognizant of the fact that valerian may exacerbate depressive symptoms.

Should you feel depressed while taking valerian, you may want to consider reducing your dosage and/or administering an adjunctive stimulatory agent (e.g. caffeine).  For most individuals, depression associated with valerian will be of mild to moderate intensity.  In rare cases, depression resulting from valerian may be severe.  That said, the side effect of depression should subside within a few days of valerian discontinuation.

Dizziness: Although many individuals administer valerian to reduce dizziness, motion-sickness, and vertigo – some valerian users note dizziness as a side effect.  Among most users, the dizziness resulting from valerian ingestion is considered mild and tolerable.  The exact cause of dizziness as a side effect of valerian isn’t understood, but it may be related to alterations in the neurotransmission of GABA and/or reduced activation of the sympathetic nervous system.

A decrease in sympathetic activation may lead to feelings of perceived dizziness and lightheadedness.  That said, users should always consider that valerian could be interacting with a simultaneously ingested supplement and/or drug.  Additionally, the dizziness could also be a transient neurophysiological reaction that may subside with continued, regular valerian usage.

Drowsiness: The single most common side effect associated with valerian supplementation is drowsiness.  This drowsiness is thought to be most noticeable following high-dose valerian administration (compared to administration of lower doses).  At higher doses, valerian suppresses CNS activity to a significant extent via modulation of GABA, thereby making users feel drowsy and/or excessively fatigued.

Since drowsiness is associated with compromised vigilance, coordination, and cognitive performance – valerian users should refrain from operating motor vehicles and/or heavy machinery in an occupational setting.  One way to minimize impairment associated with drowsiness is to take valerian at night (prior to bedtime).  However, users should be aware of the fact that morning-after or next-day drowsiness could linger from valerian, even if administered at night.

Should you experience lingering/next-day drowsiness from nighttime usage of valerian, simply ingesting a stimulatory agent (e.g. caffeine) should mitigate this side effect.  In addition to utilizing caffeine in the mornings, decreasing your nightly dosage of valerian may prove beneficial.  Realize that if the drowsiness is excessive and or causing significant impairment, valerian may be a suboptimal fit for your particular neurophysiology.

Dry mouth: Some users note that after taking valerian, their mouth dries out to a significant extent.  It has been formally documented that a subset of valerian users report dry mouth as a side effect.  Dry mouth isn’t among the most common side effects, but one that you could experience, especially if you’re taking a high dosage.

If after taking valerian, you notice that your mouth feels parched, gums lack salivary lubrication, and overall saliva production has diminished – it’s probably more than just a coincidence.  Valerian may be interfering with your salivary glands ability to manufacture saliva, resulting in dry mouth.  This in turn could cause a host of other problems such as halitosis (malodorous breath) due to infiltration of bad bacteria.

Excitability: A counterintuitive side effect that has been reported among valerian users is increased excitability.  Rather than feeling calmer and/or less excited – some individuals note increased internal excitement while supplementing with valerian.  If you’re taking valerian specifically to combat anxiety and/or insomnia – this side effect of excitability may be unwanted.

In some cases, the excitability may be transient and/or attributed to valerian when it’s really caused by something else (e.g. lack of sleep, another supplement, etc.).  It is possible that excitability may be a sign that your particular source of valerian may be poor (with abnormal biochemical constituents) and/or that you haven’t properly calibrated your dosage for an optimal response.  Most high-dose valerian users should notice a significant decrease in excitability.

Fatigue: It is understood that valerian supplementation downregulates CNS activation and increases activity of GABA (an inhibitory neurotransmitter).  For this reason, it’s no surprise to learn that a subset of users report fatigue as a side effect.  If you experience lower-than-average energy, feel lethargic, and/or have a tough time sustaining motivation throughout the day – valerian may be to blame.

If you’re feeling fatigued from valerian, the most logical solution may be to decrease the dosage.  However, if a dosage reduction doesn’t improve energy level, augmentation with a stimulatory agent may be of benefit.  Additionally, you may want to consider using valerian only at times when you don’t need significant energy (e.g. at night).

Grogginess: Regardless of when you take valerian, you may experience grogginess as a side effect.  Grogginess is considered a dazed state of functioning characterized by sleepiness, weakness, and/or foggy thinking.  This grogginess may be particularly prominent if you take valerian in the morning immediately upon waking.

Perhaps the best way to decrease likelihood of grogginess is to take valerian at the lowest effective dosage at night (prior to sleeping).  Since the side effect of feeling groggy is synonymous with other reactions such as fatigue, drowsiness, and somnolence – intervention with a stimulatory substance may be of benefit.

Headaches: Many individuals take valerian specifically to decrease the intensity of headaches and/or migraines.  Those that derive benefit from valerian for headaches likely have excess vasoconstriction due to heightened stress and/or inflammation.  However, some individuals may experience headaches as a side effect of valerian supplementation.

Headaches caused by valerian supplementation are likely an indirect cause of GABAergic modulation.  The GABAergic modulation elicited by valerian is known to decrease CNS activation, which in turn facilitates a vasodilatory response.  This vasodilation can trigger headaches via excess dilation of blood vessels and reduced blood pressure.  To combat these vasodilatory headaches, you may need to increase CNS activation.

Impaired motor skills: Valerian is a CNS depressant, and as such, it is capable of impairing fine motor skills.  For this reason, there are often safety warnings on valerian products recommending that users avoid driving and/or operating heavy machinery after supplementation.  If you are employed in a career that demands optimal coordination and fine motor skills, taking valerian may compromise your personal safety and/or the safety of fellow employees.

Similarly, athletes may also want to forgo valerian administration prior to a big game and/or event as impaired motor skills will likely be detrimental to overall performance.  Keep in mind that exact degree to which fine motor skills are impaired whilst taking valerian may be subject to individual variation.  In general, the higher the dosage of valerian ingested, the more significant the impairment of motor skills is likely to be.

Memory impairment: Some valerian users have reported short-term memory loss and/or impairment as a result of supplementation.  Memory impairment associated with valerian may be due to upregulated levels of GABA and/or its binding to the “beta subunit” of the GABAA receptors, thereby decreasing CNS activation.  Related substances such as benzodiazepines are also known to affect ability to encode memories and may lead to permanent memory impairment with long-term usage.

While permanent memory impairment isn’t a known side effect of valerian, it may affect your ability to encode new memories.  For this reason, it may be counterproductive for a student to use valerian while attempting to learn new information and/or study for an exam.  Usually the greater the dosage of valerian administered, the more substantial the memory impairment (and related cognitive deficits).

Somnolence: Among the most common valerian side effects is that of somnolence.  This side effect is synonymous with drowsiness and is characterized by a strong desire for sleep.  For some users, the side effect of somnolence may be viewed as beneficial in that it helps them overcome insomnia and get a good night’s sleep.

For other individuals, somnolence may be perceived as unwanted – particularly during the daytime.  If you experience somnolence from valerian, realize that it may be helpful to scale back on the dosage and/or adjust the time of day at which you take it.  Those experiencing somnolence throughout the day may, in addition to reducing their dosage, need to bolster arousal via ingestion of stimulatory agent.

Stomach aches: A lesser common side effect of valerian supplementation is upset stomach and/or stomach aches.  If you’re experiencing gastrointestinal irritation or a stomach ache after taking valerian, it may be due to the fact that you’re taking it on an empty stomach.  A common strategy for decreasing likelihood of supplement-induced stomach aches is to only take valerian after a large meal and/or with food.

Taking valerian with food may slow its absorption and be less likely to irritate the gastrointestinal tract.  Also consider that stomach aches could be caused by taking abnormally high dosages, interactions with other medications/supplements, or impaired hepatic metabolism.  In most cases, stomach aches resulting from valerian will be of mild discomfort.

Uneasiness: General uneasiness and malaise may occur among some individuals supplementing with valerian.  Valerian cannot be considered a universally therapeutic supplement, and for this reason, it’s no surprise that some people dislike how it makes them (subjectively) feel.  If you feel depersonalized, emotionally distraught, and/or agitated due to the neurochemical changes induced via valerian – it may be smart to simply discontinue usage.

Weird dreams: Another fairly common side effect of valerian is weird, unusual, or vivid dreams.  You may notice that your dreams are especially graphic, emotionally-charged, and or vivid after taking valerian.  While dreams in general are commonly considered “weird,” many users report exceptional oddities of dreams following valerian administration.

The perceived weirdness of dreams following valerian ingestion is likely due to neurochemical changes prior to sleep.  Altered concentrations of neurotransmitters (e.g. GABA), neural activation, and neuroelectrical activity – as a result of valerian, may be responsible for crazy dreams during supplementation.  Among valerian users, weird dreams are most common among those who take the supplement as a nighttime sleep aid.  To minimize likelihood of bizarre dreams, you could adjust the time at which you ingest valerian (prior to bed) and/or consider reducing the dosage.

Note: The aforementioned list is a compilation of all possible side effects associated with valerian.  Most users will not experience every side effect on this list and some users may experience no noticeable side effects.  If you have a question about a particular side effect and/or reaction to valerian, consult a medical professional.

Variables that influence Valerian side effects

It is necessary to realize that not all valerian users experience the same side effects.  One user may report excessive daytime sleepiness, while another may report depression and weird dreams.  The specific valerian side effects experienced, as well as their perceived intensities, are largely subject to individual variation based on variables such as: valerian dosage, co-ingested substances, frequency of administration, and valerian source/formulation.

  1. Dosage (High vs. Low)

The greater the dosage of valerian you take, the more likely you are to experience side effects.  Side effects are more common at high dosages due to the fact that the greater the quantity of valerian ingested, the more influence it has over neurophysiological processes.  Someone that’s taking 900 mg of valerian will likely experience more substantial side effects a person taking just 400 mg.

At the higher dosage, there are more biochemical compounds that necessitate metabolism, distribution, and excretion.  High-dose users experience more significant modification of GABA compared to low-dose users, and for this reason, certain side effects may only occur at high doses.  At lower dosages, valerian is less disruptive of homeostatic neurophysiology, and as a result, side effects will be less noticeable, numerous, and problematic.

  1. Co-administered substances

Anytime you’re taking valerian with another drug and/or supplement, it is necessary to consider the possibility of interaction effects.  Valerian is known to interact with other CNS depressants such as: alcohol, benzodiazepines, and muscle-relaxants – which may provoke serious adverse effects.  Some users may mistakenly attribute these adverse effects solely to the valerian, when in reality, they’re from a contraindication.

It is understood that concomitantly administered medications and/or supplements may alter the pharmacokinetics of valerian.  In other words, processes related to absorption, metabolism, and excretion of valerian may be modified by another drug or supplement – which in turn causes side effects.  Since valerian affects CYP3A4 isoenzymes, any co-administered agents metabolized via CYP3A4 may be most likely to induce side effects via pharmacokinetic interactions.

Additionally, it is necessary to consider the possibility of pharmacodynamic interactions.  Any agents that potentiate the GABAergic effects as induced by valerian, may lead to severe and/or excessive drowsiness, somnolence, and fatigue.  Certain agents may interact both via pharmacokinetics and pharmacodynamics.

That said, some co-ingested substances may attenuate side effect of valerian.  For example, someone who administers a stimulatory agent such as caffeine – may not experience side effects related to CNS depression such as drowsiness or cognitive deficits.  Therefore, if you are experiencing side effects (or no side effects) while taking valerian – it may be related to co-administered agents.

  1. Frequency of administration

How often you take valerian may also influence the side effects you experience.  Individuals that take valerian on an “as needed” basis may be more prone to certain side effects because their neurophysiology hasn’t adapted to regular ingestion of the supplement.  In some cases, frequent administration of valerian allows a user’s neurophysiology to adapt to the exogenous supplement, and incidence of side effects decreases.

On the other hand, some valerian users may develop side effects as a result of frequent dosing.  Among frequent or chronic valerian users, side effects may increase for multiple reasons.  Increased frequency of usage is often associated with greater total ingestion of valerian in a 24-hour period – a high dosage may get ingested on a daily basis; as was already mentioned – high doses increase side effect occurrence.

That said, some frequent valerian users may become tolerant to the effects of valerian at standard dosages.  As a result, high-frequency users may increase their dosage to attain the same therapeutic effects that they once reaped from a lower dosage.  However, upon the dosage increase, side effects also increase because a greater amount of valerian is influencing neurophysiological processes.

  1. Source + Formulation

Another variable that should be considered when contemplating side effects is the particular source of valerian.  Not all valerian products and/or formulations are the same.  Certain valerian products consist solely of valerian root, while others may incorporate the entire flower.

  • Biochemical content: It is also necessary to consider the geographical location from which the valerian was grown as well as how it was extracted. Differences in biochemical may be observed between multiple valerian plants grown in separate countries and/or via different extraction methods.  Although standard valerian supplements contain 0.3% to 0.8% valeric acid, differences in levels of other biochemicals may influence likelihood and/or severity of certain side effects.
  • Source: The quality of valerian attained from one source may also differ from that of another source – these differences in overall quality and/or purity may be important. Additionally, the specific formulation of valerian sold may impact side effects experienced.  If valerian is consumed as a tea, it may exert slightly different effects compared to valerian consumed in a capsule.
  • Blends: Some valerian products are blended with other herbs (e.g. lemon balm). If you’re experiencing side effects from valerian, it may be worth inspecting your product to determine whether what you’re taking is part of an herbal blend.  If the valerian is one of several herbs in a blend, the side effects may be related to the synergistic effect of the blend, or a reaction to one of the other ingredients.

Valerian: Do the benefits outweigh the side effects?

If you’re taking valerian as a dietary supplement, it is important to assess whether the benefits derived from its usage outweigh the side effects.  Some users may take valerian regularly and derive no significant therapeutic benefit such as: anxiety reduction, decreased insomnia, relaxation, sleep enhancement, or stress reduction.  Assuming you’ve been taking valerian, but aren’t getting any benefit from its usage, it makes logical sense to cease usage – after all, why pay for (and waste time ingesting) a supplement that provides no benefit?

Most valerian users will experience a combination of therapeutic benefits and side effects.  For example, some users may enjoy the relaxation they experience while taking valerian, but dislike the daytime drowsiness that it causes.  In this case, it is necessary to weigh the impairment of the daytime drowsiness with the benefit of the relaxation response.

Individuals that cannot afford to be drowsy during the day, such as those operating machinery or motor vehicles – will likely need to stop using valerian, regardless of the relaxation it provides.  Additionally, individuals that are so drowsy that they cannot pay attention in school and/or remain productive in an occupational setting – may also want to discontinue valerian.  However, if the drowsiness is relatively mild, and the relaxation is perceived as significant – the benefits may outweigh the side effects.

In a rare subset of users, significant anxiolytic benefits may be attained without any noticeable side effects.  Assuming you’re reaping the benefits without side effects – it’s a relatively easy choice to continue using.  If you need help weighing the benefits of valerian with its side effects, consult a medical professional and consider tracking your supplementation experience with a journal.

Possible ways to mitigate Valerian side effects

If you’re experiencing unwanted side effects following valerian supplementation, you may want to consider some mitigation strategies before discontinuing valerian altogether.  Strategies that may be effective for reducing the occurrence of side effects include: adjusting your dosage, eliminating other (unnecessary) supplements from your stack, taking valerian after a meal, adding other supplements, or changing your administration time.  Prior to implementing any of these side effect mitigation strategies, be sure to verify their efficacy and safety with a medical professional.

  1. Dosage reduction: For many valerian users, the easiest way to minimize the likelihood of severe side effects is to simply take a lower dose. Many individuals begin supplementing with valerian at “recommended” or even high dosages and fail to consider that the specific dosage may be too potent for their neurophysiology. If you’re experiencing side effects from valerian supplements, try taking just a fraction of your current dose.  Thereafter, adjust your intake to determine the “minimal effective dose” or the lowest possible quantity of valerian capable of providing therapeutic benefit.  The lower the dosage you take, the less likely you are to experience side effects.
  2. Divided dosing: Another strategy that may help reduce side effects of valerian is to divide your dosing. Rather than taking a single large dose of valerian once per day, you may want to divide that large dose up into 2 or 3 smaller doses. Dividing the dosages and administering them several hours apart may help ensure better absorption and metabolism and pack a less potent neurophysiological punch – leading to side effects.
  3. Avoid other substances: To determine whether valerian is the underlying cause of your side effects, you may need to eliminate all other supplements and/or drugs from your regimen; this will allow you to rule out interaction effects. In many cases, other supplements can interact via pharmacokinetics and/or pharmacodynamics. By eliminating and/or avoiding unnecessary supplements (or pharmaceuticals), side effects may diminish due to the fact that they are no longer interacting with valerian.
  4. Take with food: If you’re experiencing side effects such as gastrointestinal distress and/or stomach aches following valerian supplementation, it could be a result of ingestion with an empty stomach. Many individuals find that taking supplements like valerian on an empty stomach causes pain and/or other side effects. When valerian is taken on an empty stomach, it is likely absorbed at a quicker pace, leading to unwanted side effects.  Try taking valerian along with food and/or after a large meal to determine whether this ameliorates side effects.
  5. Co-supplementation: While elimination of supplements and/or drugs can decrease interaction effects, sometimes strategic co-supplementation may be helpful in reducing side effects. For example, if valerian makes you feel exceptionally drowsy during the day, you may want to attenuate this drowsiness via administration of another substance such as caffeine. Obviously you won’t want the adjuvant substance to interfere with the therapeutic efficacy of valerian or induce contraindications, so discuss hypothetical pharmacological augmentation with a medical professional.
  6. Continue using: Certain users may find that the side effects experienced during the first week of valerian supplementation tend to subside in successive weeks. If you’ve been using valerian for an extremely short-duration (e.g. a day or two), it is necessary to consider that you may need to wait a few more days for your body to acclimate itself to the exogenous, supplemental valerian. Upon acclimation to the valerian (with continued usage), side effects may diminish and/or abate.

Have you experienced Valerian side effects?

If you’ve supplemented with valerian, feel free to share a comment mentioning whether you experienced any side effects.  Among those that have experienced side effects, which were the most severe and/or problematic?  Did the side effects you experienced improve over time (with regular valerian administration) or did they cause you to give up on valerian as a supplement?

To help others get a better idea of your situation, mention some details such as: the brand/format of valerian you took, the dosage, condition treated, as well as whether you were taking any other drugs or supplements along with it.  Among most valerian users, the most commonly reported side effects are drowsiness and somnolence – which likely occur as a result of its ability to modulate GABAergic activity.  Although valerian is usually regarded as safe with minimal side effects, no supplement (even if “all natural”) can be considered utopian – always listen to your body and trust that if you don’t react well to it there are plenty of other options.

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1 thought on “Valerian Side Effects & Adverse Reactions (List)”

  1. Valerian and GABA are overly stimulating to me and my daughter. It gives us insomnia and irritability. I assume they may be stimulating glutamate and that maybe we lack the enzyme that converts glutamate to GABA. We may have a genetic SNP (GAD) or GAD auto-antibodies.


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