Valerian - Scientific Background
Valerian improves sleep better than placebo.
Evidence for improved sleep from clinical trials in humans is limited, and results are moderately positive (Balderer and Borbely 1985; Schulz et al 1994).
In the largest controlled study of 128 asymptomatic persons, the participants reported a subjective improvement in sleep quality for valerian extract compared to a placebo (Leathwood et al 1982). For participants taking the valerian extract, the greatest improvements were reported by those considering themselves to be poor sleepers.
In another controlled trial a valerian preparation containing primarily fat-soluble compounds (sesquiterpenes) improved poor sleep significantly more than the placebo. A high proportion of participants in the valerian group reported improved sleep (Lindahl and Lindwall 1989).
Valerian improves sleep as much as certain sleep medications.
A randomized trial among 80 healthy volunteers with no sleep problems compared a valerian syrup and a combination tablet of valerian and hops (another herb with a sleep-promoting effect) to a prescription sedative and to a placebo (Gerhard et al1996). All three active treatments resulted in subjective reports of better sleep, while only the prescription sedative (flunitrazepam, a benzodiazepine drug) resulted in impaired vigilance and decreased dexterity on the following morning (hangover effect).
A combined preparation of hops and valerian was found to be as effective as the sleep medication benzodiazepine (Schmitz and Jackel 1998). One person in the valerian group and one person on the benzodiazepine group had stomach complaints.
Because of the known side effects and risk of dependence for benzodiazepine sleeping pills, recent reviews recommend that plant-based sedatives be evaluated in adequately controlled randomized trials among people with sleep problems (Cott 1995; Wagner et al 1998).
At this time, the U.S. Pharmacopeia does not recommend the use of valerian (www.usp.did/mgraphs/botanica/valeria2.htm).
The effect of valerian may vary from person to person.
Valerian roots contain numerous substances that act on various structures of the nervous system (Mennini et al 1993). Many of these structures, such as receptors on the surface of nerve cells, are variable among individuals; thus, people are likely to differ in what they experience after taking valerian extracts.
The potency of valerian may vary from preparation to preparation.
The concentration of some of the presumed active ingredients in valerian varies with the season and time at which the root is harvested, accounting for the fluctuating potency of valerian preparations (Bos et al 1998).
