Valerian for sleep: what the trials show

What is valerian?

Valerian is a flowering plant whose dried root has been used as a sleep remedy since Roman times. In the UK it’s sold in tablets, capsules and teas, often combined with hops or passionflower. Many products carry a THR (traditional herbal registration) mark, which means they meet quality and safety standards, but their use is based on long tradition rather than trial evidence.

Does it work?

The trials point in different directions.

• A 2006 review of 16 studies with 1,093 people found those taking valerian were about 1.8 times as likely to report improved sleep as those on placebo. But the authors found signs of publication bias, meaning positive trials were more likely to be published than negative ones, and many studies were small or poorly run.
• A 2010 review of 18 randomised trials found no meaningful difference in the time it took to fall asleep, measured objectively: less than a minute. Scores for sleep quality didn’t differ either, though people on valerian were somewhat more likely to say their sleep had improved.
• A US trial of 184 adults compared a valerian-hops combination for 28 days, the antihistamine diphenhydramine (as in Nytol) for 14 days, and a placebo. Both active treatments had modest effects, and few differences from placebo were statistically significant.

Put together, valerian may help some people feel they sleep better, but there’s no convincing evidence that it changes how quickly you fall asleep or how long you sleep. US sleep medicine guidelines advise against it for chronic insomnia.

Is it safe?

For most healthy adults, short courses seem low risk. Reported side effects include headache, dizziness, stomach upset and feeling groggy the next morning. There have been rare reports of liver problems with valerian products, though often in combination with other herbs.

Don’t take valerian if you are pregnant or breastfeeding, or give it to children, without medical advice, because it hasn’t been tested in these groups. Avoid alcohol, and don’t combine it with other sleep aids or sedatives. Ask a pharmacist first if you take other medicines or have liver disease.

Should you try it?

If you want a herbal remedy for a short bad patch, a THR-marked valerian product is a reasonable thing to try for a few weeks, as long as you don’t expect much. For insomnia lasting months, CBT for insomnia has far better evidence.