Research review
Skullcap benefits: what the research does and doesn't show
Two small trials of American skullcap found mixed results on anxiety and mood in healthy adults; Chinese skullcap has no human trials on any mental-health outcome at all.
The evidence doesn't support skullcap, in either the American or Chinese species, as a treatment for any condition. Human research is thin: two small trials of American skullcap tested mood and anxiety in healthy volunteers, with mixed and modest results, and no controlled human trial of Chinese skullcap for a mental-health outcome exists at all.
What the evidence doesn't support
It doesn't support skullcap — American or Chinese — as a treatment for anxiety, panic disorder, generalized anxiety disorder, or insomnia. It doesn't support skullcap as more effective than a placebo for anyone outside the small, healthy, mildly-anxious samples the two existing human trials recruited. And it doesn't support treating the two species as interchangeable: almost everything below is specific to Scutellaria lateriflora (American skullcap); Chinese skullcap's research is almost entirely lab and animal work, not human trials.
What the trials found
A 2014 randomized, double-blind, placebo-controlled crossover trial gave 43 healthy adults 350 mg of American skullcap three times a day (1,050 mg total) or placebo, each for two weeks. Most participants started only mildly anxious or less. Anxiety scores on a standard scale didn't differ significantly between skullcap and placebo. A separate mood measure did show a significant drop in total mood disturbance with skullcap but not placebo — but the trial had a carryover effect between its two study phases and uneven anxiety levels between groups at the start, both of which the authors said could have masked a real difference, or exaggerated one. Skullcap didn't reduce participants' energy or mental performance in this trial.
An earlier, smaller 2003 double-blind, placebo-controlled trial in healthy volunteers reported an anxiolytic effect for American skullcap, but its published abstract doesn't report the dose used, and the same paper noted "controversy in the literature" about whether skullcap works at all — a debate that predates and postdates this trial.
A 2011 review of herbal medicines for depression, anxiety and insomnia — which searched multiple databases for controlled trials — found only these same two American skullcap trials and listed the herb among several with "preliminary positive evidence," a lower tier than herbs like St. John's wort or kava, which the review found supported by a larger number of replicated trials. The review's authors cautioned that many of the studies they covered, skullcap's included, haven't been replicated.
No trial has tested Chinese skullcap, alone, on anxiety, mood, sleep, or any other mental-health outcome in people. Lab work has found an isolated flavonoid from Chinese skullcap's root binds the same brain receptor site as the drug diazepam and reduces anxiety-like behavior in mice — see what is skullcap for that study's details — but an isolated compound tested in mice is a different thing from the whole herb tested in a person, and nobody has closed that gap.
| Study | Species | Design | Population | Result |
|---|---|---|---|---|
| Brock et al., 2014 | American | RCT, crossover, 2 weeks | 43 healthy adults, mostly mildly anxious | No significant difference on anxiety scale; mood measure improved |
| Wolfson & Hoffmann, 2003 | American | RCT, dose not reported | Healthy volunteers | Reported anxiolytic effect |
| Sarris et al., 2011 (review) | Multiple herbs incl. American skullcap | Systematic review | — | Skullcap listed as "preliminary positive evidence," not replicated |
Questions people ask
What is skullcap used for?
Traditionally, a calming herb for nervous tension, used as a tea, tincture or capsule. In research, the two trials above tested American skullcap for mood and anxiety in healthy adults with mixed results; nothing has been tested for any other specific use.
What does skullcap do?
Based on the trials above, it's unclear whether American skullcap does anything measurable for a healthy adult's anxiety beyond placebo — one of two small trials found no significant difference on a standard anxiety scale. Chinese skullcap hasn't been tested on any mental-health outcome in people at all.
Is Chinese skullcap good for anything specific?
Not that human trials have established. Chinese skullcap's root has been studied mostly for its effect on drug-metabolizing enzymes (covered in skullcap and medications: what to check) and in lab and animal experiments, not in human trials for a specific health outcome.
Does skullcap tea do the same thing as the trials tested?
No trial has tested skullcap tea specifically — both human trials used capsules at a stated dose (350 mg, three times a day, in the larger trial). A cup of tea made from dried herb delivers an unknown and variable amount by comparison.
Is skullcap good for hair?
No trial has tested skullcap, taken orally or applied topically, on hair growth or hair health in people.
Does skullcap actually work?
For what, is the honest first question — nothing has been tested for most of what people search for it hoping to fix. The narrowest, best-supported claim available is that one 2014 trial found American skullcap improved a mood-disturbance score relative to placebo, in healthy adults, over two weeks, while a standard anxiety-scale result from the same trial showed no difference. That's a real but modest and unreplicated result, not evidence the herb works broadly.
Is there newer or better research than these two trials?
Not for humans. Searches of the published literature turn up these same two American skullcap trials repeatedly, and no controlled human trial of Chinese skullcap for any mental-health outcome. Most of what's published on skullcap since is lab chemistry, animal behavior testing, or research on unrelated uses of its compounds — not new human evidence for the uses people search for most.
When to talk to a doctor
Skullcap is not a treatment for anxiety, panic disorder, generalized anxiety disorder or insomnia, and nothing in the research above supports using it as a substitute for an evaluation, therapy or medication a doctor might recommend. Persistent anxiety or sleep trouble that interferes with daily life is worth raising with a doctor. If you take a prescription medication or are pregnant or nursing, talk to a doctor before adding any supplement.
Related reading: what is skullcap, skullcap side effects, and skullcap and medications: what to check.
Sources
- American Skullcap (Scutellaria lateriflora): a randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers A 2014 randomized trial found no significant difference between American skullcap and placebo on a standard anxiety scale, though a separate mood measure improved; the trial had carryover and baseline-imbalance limitations.
- An investigation into the efficacy of Scutellaria lateriflora in healthy volunteers A 2003 double-blind, placebo-controlled trial in healthy volunteers reported an anxiety-reducing effect for American skullcap, though the paper itself noted ongoing controversy over whether the herb works, and its abstract doesn't state the dose used.
- Herbal medicine for depression, anxiety and insomnia: a review of psychopharmacology and clinical evidence A 2011 review of herbal medicine trials for anxiety, depression and insomnia rated American skullcap's evidence as only "preliminary positive," a lower tier than herbs with a larger body of replicated trials, and cautioned that many of the studies it covered haven't been repeated.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.