Valerian root

What it is

Valerian is a flowering plant whose root has been used as a calming remedy since ancient times. The dried root has a strong smell that many people describe as like old socks.

It is sold in the UK as a traditional herbal medicine for temporary relief of mild anxiety and to help with sleep, and is often combined with hops, lemon balm or passionflower.

How it works

It may increase levels of GABA, a calming brain chemical, and interact with receptors involved in sleep. The exact active components are unclear, which makes standardisation tricky.

What the evidence says

• Limited Falling asleep faster
  Some small trials show slight benefit; reviews find results inconsistent and often low quality.
• Limited Sleep quality
  Subjective improvement reported by some users, but effects vs placebo are small.
• Weak Mild anxiety and stress
  Not enough high-quality evidence.
• Weak Menopausal sleep problems
  Small studies only.

Evidence ratings are our plain-English summary of how much good human research exists, not a promise of results. How we rate evidence.

Dosage and timing

• Labels commonly suggest 300-600 mg of extract before bed, per product instructions.
• Some traditional medicine products suggest smaller daytime doses for stress.
• It is generally intended for short-term use; long-term safety data is limited.
• Do not drive or use machinery if you feel drowsy.

Forms and what to look for

• Registered traditional herbal products (THR) are the most reliable UK option.
• Standardised dry extract capsules give more consistent dosing than teas.
• Teas are mild and unpredictable.
• Combination products may change both effect and interactions.

What to expect, and when

• Some people notice an effect the first night; most trials suggest benefits, if any, build over 2-4 weeks.
• If nothing changes after a few weeks, it is probably not for you.
• Persistent insomnia lasting a month or more is worth discussing with a GP.

Side effects

• Drowsiness and grogginess the next day.
• Headache, dizziness or stomach upset.
• Vivid dreams.
• Rarely, paradoxical stimulation or restlessness.

Interactions

• Alcohol, sedatives, sleeping tablets, benzodiazepines and other sedating medicines: additive drowsiness.
• Other calming herbs such as kava or passionflower: additive effects.
• May affect some liver enzymes in theory; evidence is limited.
• Anaesthetics: stop before planned surgery as advised by your clinician.

Who should avoid it

• Pregnancy and breastfeeding, due to limited safety data.
• Children under 12 unless advised by a clinician.
• People with liver problems.
• Anyone who needs to drive or stay alert soon after dosing.
• Anyone taking sedative medicines, unless advised by a pharmacist.

Risks and safety

• Rare reports of liver problems with valerian-containing products, though a causal link is unclear.
• Withdrawal-like symptoms have been reported after abrupt stop of heavy long-term use, in case reports.
• Mixed products may contain other active herbs.
• Supplement quality and strength vary.

Buying well: quality and testing

• In the UK, look for THR-registered products.
• Standardised extracts with a stated mg are preferable to loose root.
• Fresh product has a strong smell; completely odourless capsules may be very weak or old.
• Avoid products that list a blend without individual doses.

Bottom line

Valerian is a low-drama option that some people find helpful and others find does nothing. It is best used briefly, alongside good sleep habits, and not combined with alcohol or sedatives. If poor sleep goes on for weeks, speak to a GP rather than escalating herbal products.