Valerian

Valeriana officinalis is a flowering plant native to Europe and Asia, whose root has been used for sleep and calm since at least classical antiquity.

The smell is worth mentioning up front. Dried valerian root smells strongly of old socks or unwashed feet, caused by isovaleric acid developing as the root dries. This is normal and not a sign of a poor product, but it is a shock if unexpected, and capsules exist largely because of it.

The active compounds are debated. Valerenic acid is the usual standardisation marker, alongside valepotriates, though it is likely that several constituents contribute rather than one dominating.

Valerenic acid appears to modulate GABA-A receptors, the main calming receptor system in the brain, binding at a site distinct from where most calming compounds act.

Valerian also appears to inhibit the enzyme that breaks down GABA, which would raise its availability, and there is evidence of interaction with adenosine and serotonin receptors.

The multiple mechanisms and multiple candidate compounds are part of why the evidence is messy. Different extracts contain different proportions of the constituents, and standardisation practice varies, so trials are not always studying the same thing.

Systematic reviews of valerian for sleep have reached inconsistent conclusions. Some report improvements in subjective sleep quality; others find effects no better than placebo, particularly when objective sleep measures are used rather than questionnaires.

A recurring observation is that effects appear more consistently after two to four weeks of nightly use than after a single dose. Valerian is not a knockout on the first night, and expecting that is the most common reason people conclude it does nothing.

Trial quality and extract variability are the main problems in this literature. The honest position is that valerian has a long history, a plausible mechanism, and an evidence base that has not settled the question either way.

Valerian is generally well tolerated. Reported effects include morning grogginess, headache, digestive upset and, paradoxically in a minority of people, feeling more alert rather than less.

Combining it with alcohol or with anything else that causes drowsiness will compound the effect, and it should not be taken before driving.

Long-term data beyond a few months is limited. Some users report grogginess on stopping after extended use. Speak to your doctor before use if you take regular medication, particularly anything acting on the brain or nervous system.