Valerian Interactions with Medication: What to Know

Yes, valerian can, in theory, interact with medicines that act on the central nervous system or that are metabolised in the liver — but the clinical evidence is weak and, for most medicines, the risk is theoretical and not confirmed in trials. The two exceptions to take more seriously are sedatives (benzodiazepines, zolpidem) and anticoagulants, because of the possibility of additive effects. If you take regular medication, the practical answer is simple: speak to your doctor or pharmacist before starting valerian, and never adjust or stop a medicine on your own initiative.

This article explains what is known about how valerian is metabolised, what trials actually measured, what is only speculation, and how to decide safely. If you are still deciding whether the plant makes sense for you, start with how valerian works and what the science says.

What is valerian and how does it act in the body?

Valerian (Valeriana officinalis) is a plant that has been used for centuries as a sleep aid. Its constituents include valerenic acid and valepotriates, and research suggests that part of the sedative effect may involve interaction with the GABAergic system — the same system that benzodiazepines act on. A systematic review of plants and the GABA system describes that extracts such as valerian may exert part of their hypnotic and anxiolytic activity through interaction with GABA receptors ¹.

This is relevant to interactions: if valerian acts (even in a mild and poorly quantified way) on the same system as sedatives, the sum of the effects is a biologically plausible possibility. But plausibility is not proof. The clinical effect of valerian is modest and inconsistent — a meta-analysis of 14 randomised trials with 1,602 participants with insomnia found no statistically significant difference between plants (including valerian) and placebo in any of the 13 efficacy measures assessed ². If the effect is uncertain, the risk of interaction is also difficult to predict precisely.

Does valerian interfere with how medicines are metabolised?

Many medicines are processed by cytochrome P450 enzymes in the liver. If a plant inhibits or induces these enzymes, it can change the concentration of the medicine in the blood — and, with it, the risk of adverse effects or loss of efficacy. This is where valerian has been studied most.

The available evidence is, on the whole, reassuring. In a trial with 12 healthy volunteers, taking 1,000 mg of valerian per night for 14 days did not alter CYP2D6 activity and had only minimal effects on CYP3A4 ³. In another study, 12 healthy volunteers received valerian for 28 days and no relevant changes were seen in the activities of CYP1A2, CYP2D6, CYP2E1 or CYP3A4/5 ⁴.

A clinical review of supplement–medicine interactions classifies valerian among the supplements with a low probability of clinically relevant interactions, and it can, with certain caveats, be taken with most medicines ⁵. This does not mean zero risk: it means that, in studies in healthy humans, the signal that was feared was not found.

Sedatives and anxiolytics: the most cited interaction

Benzodiazepines (diazepam, lorazepam, alprazolam), zolpidem and medicines with a sedative effect act on the central nervous system. Because valerian also appears to act there, the combination could, in theory, add to drowsiness, dizziness and difficulty concentrating.

What studies show is limited. In a randomised, double-blind, crossover trial with 20 anxious patients undergoing third molar extraction, valerian 100 mg was compared with midazolam 15 mg (a benzodiazepine) taken 60 minutes before the procedure: midazolam was more effective at reducing the physiological parameters studied, and drowsiness was the most common side effect in both groups ⁶. In other words, valerian had a noticeable sedative effect — which reinforces caution with the combination, even without direct interaction data.

An interesting finding comes from a trial with 19 patients with primary insomnia who had been taking benzodiazepines for several years: after the medicine was withdrawn, valerian improved subjective sleep quality compared with placebo, but part of the differences in sleep structure could be due to recovery after stopping the medicine itself ⁷. None of this indicates that valerian replaces a prescribed sedative — and it should not be used to "taper off" medication without medical supervision.

Anticoagulants and antiplatelet agents: the most serious risk

This is the category where caution should be greatest. There are reports of possible interference by valerian with clotting and of potentiation of the effect of anticoagulants, although the mechanisms are not clear and there are no controlled trials confirming it. The review of supplement–medicine interactions classifies valerian among the supplements with a low probability of clinically relevant interactions, but stresses that case-by-case assessment is needed ⁵.

In practice: if you take warfarin, apixaban, rivaroxaban, clopidogrel or aspirin at antiplatelet doses, do not start valerian without speaking to the doctor who prescribes the anticoagulant. The potential for harm (bleeding) justifies caution, even with weak evidence.

Antidepressants, blood pressure medicines and other drugs

For antidepressants (SSRIs such as fluoxetine or sertraline, or tricyclics), there are no human interaction studies with valerian. The warning about a possible serotonin syndrome is theoretical and has no confirmed cases. Even so, because many antidepressants have a sedative effect, the sum with valerian may increase drowsiness.

For blood pressure medicines, the concern is a possible additive hypotensive effect. There are no clinical data confirming it; if you take medication for blood pressure, monitor your blood pressure and tell your doctor that you use valerian.

As for common painkillers, antibiotics or oral contraceptives, there are no documented interactions. The rule remains: always tell your healthcare professional about all the supplements you take.

Quick comparison: which medicines need the most care?

Medicine group	Level of concern	What the evidence shows
Sedatives and anxiolytics (benzodiazepines, zolpidem)	Moderate	Valerian's sedative effect was observed in a clinical trial; the risk of additive drowsiness is plausible, with no direct interaction trials 6
Anticoagulants and antiplatelet agents	High (caution)	Reports of possible interference with clotting, without confirmation in controlled trials; the potential for harm justifies caution
Antidepressants (SSRIs, tricyclics)	Low to moderate	No interaction studies; theoretical warning of serotonin syndrome not confirmed
Blood pressure medicines	Low	Possible additive hypotensive effect, without clinical data
Medicines metabolised by CYP3A4, CYP2D6, CYP1A2, CYP2E1	Low	Trials in healthy volunteers showed no relevant changes in enzyme activity 34
Common painkillers, antibiotics, contraceptives	Low	No documented interactions

Groups who should avoid valerian without medical supervision

• Pregnant and breastfeeding women: there are not enough safety data; the recommendation is not to use it without professional advice.
• Older people: they are more sensitive to sedative effects, have a higher risk of falls and often take several medicines — the likelihood of interaction goes up.
• Children: they should not take valerian without paediatric advice. Never give doses to children on your own.
• People with liver disease or who take several medicines: the liver is the central organ in the metabolism of valerian and of medicines; speak to your doctor first.

If you are pregnant or breastfeeding, see also valerian in pregnancy: what to know before you take it.

What about alcohol? And other sedative supplements?

Alcohol is a central nervous system depressant. Combining it with valerian can increase drowsiness and impair coordination — and the same reasoning applies to other supplements with a sedative effect, such as melatonin or passionflower. There are no specific studies on these combinations, but caution suggests avoiding them, especially if you are going to drive or operate machinery.

If you are looking for alternatives with their own evidence, you can explore GABA and what is known about GABA safety and contraindications.

What a valerian product label says

Labels on valerian supplements usually include generic but important warnings: do not exceed the recommended daily dose, keep out of the reach of children, and consult a healthcare professional if you have an illness or are taking medicines. These warnings exist precisely because interactions, even when theoretical, cannot be ruled out without individual assessment.

If you are looking for a product in the range, see the valerian gummies and the ingredient page for valerian, where the composition and how to use it are described. Doses used in studies are not instructions for use: always follow the label and, if you take medication, the advice of your healthcare professional.

What to do if you want to take valerian and you are on medication

1. Make a complete list of your medicines (prescription and over-the-counter) and supplements.
2. Take that list to your doctor or pharmacist and ask directly whether you can take valerian with them.
3. Do not stop or change any medicine on your own initiative to test valerian.
4. If you start, start with the label dose and observe how you feel in the first few weeks.
5. If you feel excessive drowsiness, dizziness, irregular heartbeat or any unusual symptom, stop and seek medical help.

To understand whether the plant makes sense for your situation, see valerian: benefits, what the science says and how to use it and does valerian have side effects? What you need to know before taking it. And if the goal is to sleep better, there are sleep hygiene measures with more evidence than any plant — it is worth starting there.

Frequently asked questions

Does valerian interact with benzodiazepines such as diazepam or alprazolam?

The interaction is possible in theory, because both act on the central nervous system and may add to drowsiness. In a clinical trial, valerian had a noticeable sedative effect in anxious patients, although less marked than midazolam. There are no direct interaction trials, so the safest option is to speak to your doctor before combining them.

Can I take valerian if I take anticoagulants such as warfarin?

You should not start without speaking to the doctor who prescribes the anticoagulant. There are reports of possible interference by valerian with clotting and of potentiation of the anticoagulant effect, although without confirmation in controlled trials. Because the potential for harm is serious, caution is essential.

Does valerian change how other medicines are metabolised in the liver?

In studies in healthy volunteers, valerian showed no relevant changes in the enzymes CYP2D6, CYP1A2, CYP2E1 and CYP3A4/5, which metabolise many medicines. A clinical review classifies it as having a low probability of clinically relevant interactions. Even so, case-by-case assessment is needed.

Can valerian replace a medicine for sleep or anxiety?

No. The evidence on valerian's efficacy in insomnia is inconsistent and, in a meta-analysis of 14 trials, no significant difference from placebo was found. Using it to reduce or stop a prescribed medicine is dangerous and should be discussed with your doctor.

Who should not take valerian?

Pregnant women, breastfeeding women and children should not take valerian without professional advice, due to a lack of safety data. Older people and people with liver disease or who take several medicines should speak to their doctor first, because of the higher risk of sedation and interactions.

What if I take the contraceptive pill or common painkillers?

There are no documented interactions between valerian and oral contraceptives, paracetamol or ibuprofen. The general rule remains: always tell your doctor or pharmacist about all the supplements you take, especially if your medication is regular.