Valerian is one of those herbs that has been around for so long that your grandmother’s grandmother probably knew about it. Europeans have been using valerian root since at least the 18th century, though ancient Greek and Roman physicians wrote about it much earlier. The root of the Valeriana officinalis plant gets dried and processed into supplements, teas, and tinctures that people take mainly for sleep problems and anxiety.

But does valerian actually work? I’ve gone through the clinical research to give you an honest picture of what this herbal remedy can and cannot do.

What is valerian?

Valerian belongs to the honeysuckle family, which includes about 200 species worldwide. The medicinal variety (Valeriana officinalis) grows wild across Europe, Asia, and North America. The name comes from the Latin valere, meaning “to be strong” or “to be healthy.”

The root contains a complicated mix of compounds: essential oils, sesquiterpenes, valerenic acid (and related compounds), various amino acids including arginine, GABA, glutamine, and tyrosine, plus some alkaloids. Researchers still debate which components are responsible for valerian’s effects, though valerenic acid gets the most attention because it appears to interact with GABA receptors in the brain.

One thing to know upfront: valerian smells terrible. The root produces a distinctive odour that most people find unpleasant, which is why valerian supplements typically come in capsule form rather than as loose powder.

What the clinical evidence shows

1. Sleep problems

Sleep disorders affect a staggering number of people. In the United States and Europe combined, over 70 million adults report chronic sleep difficulties. Poor sleep does more than leave you tired; it affects mood, memory, concentration, and long-term metabolic health, contributing to conditions like high blood pressure, dyslipidaemia, cardiovascular disease, and type 2 diabetes [1].

Valerian has been the subject of numerous sleep studies, though I should be upfront: the research quality varies considerably.

A systematic review and meta-analysis looked at 18 randomised controlled trials of valerian for sleep [2]. The findings were mixed. When participants simply rated whether their sleep had improved (yes or no), valerian beat placebo. But when researchers used more precise measurements like visual analogue scales to quantify sleep quality and the time it takes to fall asleep, the difference between valerian and placebo disappeared.

What does this mean? Valerian might help people feel like they’re sleeping better, even if objective measures don’t show dramatic changes. The NHS notes that valerian is commonly used as a sleep aid but advises that more research is needed to confirm whether it works [3].

My honest assessment: if you’re dealing with mild sleep difficulties and want to try something gentle, valerian is unlikely to cause harm. But don’t expect miracles. For serious insomnia, you’ll probably need to address the underlying causes rather than rely on a supplement.

2. Anxiety

Generalised anxiety disorder affects up to 20% of adults in any given year, with women experiencing it two to three times more often than men [4]. The condition involves persistent worry about everyday things, from finances to health to relationships, along with physical symptoms like restlessness, muscle tension, and difficulty concentrating.

The evidence for valerian in anxiety is thinner than for sleep. One randomised, placebo-controlled pilot study tested valerian extract (specifically the valepotriate compounds) in 36 outpatients diagnosed with generalised anxiety disorder [5]. After four weeks, the valerian group showed some improvement compared to placebo.

Thirty-six patients. That’s a small study. It’s suggestive but hardly conclusive. Larger trials haven’t consistently replicated these findings, and nobody has established what dose or preparation works best.

If you’re dealing with significant anxiety, valerian on its own probably won’t cut it. That said, some people find it takes the edge off, particularly when anxiety interferes with sleep. The two conditions often go hand in hand.

3. Menopausal hot flashes

Hot flashes affect most women going through menopause and can persist for years. These episodes involve sudden feelings of heat, sweating, flushing, and sometimes anxiety or chills, typically lasting one to five minutes. They result from changes in the hypothalamus (the brain’s thermostat) as oestrogen levels decline.

Hormone replacement therapy remains the most effective treatment, but not everyone can or wants to use it. That’s driven interest in alternatives like valerian.

A three-blind randomised trial enrolled 60 postmenopausal women aged 45 to 55 and compared valerian capsules (530 mg twice daily) against placebo over three months [6]. The valerian group experienced significantly fewer and less severe hot flashes.

This is encouraging, but again, it’s one study with 60 participants. The effect sizes were modest, and nobody has replicated the findings in larger populations. I wouldn’t recommend valerian as a first-line treatment for severe hot flashes, but if you’re looking for a gentle supplement to add to other lifestyle measures, it might be worth trying.

Side effects

Valerian appears on the US FDA’s GRAS (Generally Recognised as Safe) list, meaning it can be used as a food ingredient. For most healthy adults, short-term use (4 to 8 weeks) seems well tolerated [7].

Reported side effects include:

Headache
Stomach upset and nausea
Dizziness or mental sluggishness
Restlessness or excitability (paradoxically, in some people)
Diarrhoea
Heart palpitations
Dry mouth or metallic taste
Vivid dreams
Daytime drowsiness

The drowsiness deserves emphasis. Valerian can make you sleepy, which is often the point, but it means you shouldn’t drive or operate machinery after taking it.

Safety precautions (11 contraindications)

Pregnancy and breastfeeding: Don’t use valerian if you’re pregnant, breastfeeding, or giving it to children under 3 years old. The safety data simply doesn’t exist for these groups.
Before surgery: Stop taking valerian at least two weeks before any scheduled surgery. It can slow down your central nervous system and potentially interact with anaesthesia.
With other sedatives: Avoid combining valerian with other herbs or supplements that cause drowsiness. This includes 5-HTP, California poppy, catnip, chamomile, gotu kola, Jamaican dogwood, kava, melatonin, St John’s wort, skullcap, and yerba mansa.
Driving and machinery: Don’t drive or operate dangerous machinery after taking valerian, especially until you know how it affects you.
Withdrawal risk: Long-term users who stop abruptly may experience withdrawal symptoms, including heart problems or delirium in severe cases. If you’ve been taking valerian regularly for weeks or months, taper off gradually over one to two weeks rather than stopping suddenly.
Alcohol: Mixing valerian with alcohol can increase drowsiness beyond what either would cause alone. This combination can be dangerous.
Prescription sedatives and sleep aids: Don’t combine valerian with benzodiazepines (alprazolam, clonazepam, diazepam, lorazepam, midazolam, temazepam, triazolam), barbiturates (pentobarbital, phenobarbital, secobarbital, thiopental), opioids (fentanyl, morphine), or anaesthetics like propofol. The combined sedation can be excessive.
CYP3A4-metabolised medications: Valerian may affect liver enzymes, particularly cytochrome P450 3A4. This could alter how your body processes certain medications, including lovastatin, ketoconazole, itraconazole, fexofenadine, triazolam, and some antihistamines. Consult your doctor or pharmacist if you take any of these.
Allergic reactions: Seek immediate medical attention if you develop hives, difficulty breathing, or swelling of the face, lips, tongue, or throat after taking valerian. These could indicate a serious allergic reaction.
Multiple health conditions: Speak with a healthcare professional before using valerian if you have any of the following: HIV or other infections (including malaria or tuberculosis), mental health conditions including anxiety or depression (even though valerian is sometimes used for these, professional guidance matters), asthma or allergies, cancer, erectile dysfunction, gastro-oesophageal reflux, high blood pressure, high cholesterol, heart disease, migraines, psoriasis, rheumatoid arthritis or other autoimmune conditions, epilepsy.
Overdose and liver concerns: Taking too much valerian over extended periods could potentially cause liver damage. Warning signs include nausea, upper abdominal pain, itching, fatigue, loss of appetite, dark urine, pale stools, or yellowing of the skin or eyes. If you notice any of these, stop the supplement and see a doctor promptly.

How to use valerian

If you decide to try valerian, typical doses in studies have ranged from 300 to 600 mg of extract taken 30 minutes to two hours before bed [8]. For anxiety, some people split the dose and take smaller amounts throughout the day.

Valerian doesn’t work immediately like a sleeping pill. Most studies that showed benefits ran for at least two to four weeks, so give it time before deciding whether it helps you.

Quality varies between products. Look for standardised extracts that specify the amount of valerenic acid, though admittedly this information isn’t always available on consumer products.

What works alongside valerian

Poor sleep and anxiety rarely have single causes. If you’re struggling, consider whether these factors apply:

Irregular sleep schedule
Caffeine or alcohol consumption, especially in the evening
Screen time before bed
Lack of physical activity
Underlying conditions like nocturia (needing to urinate at night) or overactive bladder
Chronic stress without adequate coping strategies

Addressing these lifestyle factors will likely help more than any supplement. Valerian might provide a gentle nudge in the right direction, but it won’t compensate for habits that undermine your sleep.

The bottom line

Valerian has a long history of traditional use and appears relatively safe for short-term supplementation in healthy adults. The clinical evidence suggests modest benefits for subjective sleep quality, with less convincing data for anxiety and menopausal hot flashes.

If you’re expecting dramatic effects, you’ll probably be disappointed. But if you’re looking for something gentle to support your sleep routine while you work on bigger-picture lifestyle changes, valerian is a reasonable option to discuss with your healthcare provider.

References

Chattu VK, Manzar MD, Kumary S, et al. The Global Problem of Insufficient Sleep and Its Serious Public Health Implications. Healthcare (Basel). 2018;7(1):1. doi:10.3390/healthcare7010001
Fernández-San-Martín MI, Masa-Font R, Palacios-Soler L, et al. Effectiveness of Valerian on insomnia: a meta-analysis of randomized placebo-controlled trials. Sleep Med. 2010;11(6):505-511. doi:10.1016/j.sleep.2009.12.009
NHS. Herbal medicines. https://www.nhs.uk/conditions/herbal-medicines/ (accessed January 2024)
Wittchen HU. Generalized anxiety disorder: prevalence, burden, and cost to society. Depress Anxiety. 2002;16(4):162-171. doi:10.1002/da.10065
Andreatini R, Sartori VA, Seabra ML, Leite JR. Effect of valepotriates (valerian extract) in generalized anxiety disorder: a randomized placebo-controlled pilot study. Phytother Res. 2002;16(7):650-654. doi:10.1002/ptr.1027
Mirabi P, Mojab F. The effects of valerian root on hot flashes in menopausal women. Iran J Pharm Res. 2013;12(1):217-222.
National Institutes of Health. Valerian. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Valerian-HealthProfessional/ (accessed January 2024)
Mayo Clinic. Valerian. https://www.mayoclinic.org/drugs-supplements-valerian/art-20360063 (accessed January 2024)