Scutellaria lateriflora L. · herb
Evidence tier: insufficient
A nervine for nervous tension without drowsiness. Particularly suited to mental restlessness with muscle tension.
The proposed mechanism is that skullcap flavonoids, chiefly baicalin and baicalein, interact with GABA A receptors, the same broad target family that benzodiazepines act on, producing calm without heavy sedation. This is a receptor binding hypothesis from laboratory work. The one decent human trial failed to show an anxiolytic effect against placebo, so the mechanism currently explains something that has not been shown to happen. Note also that baicalin and baicalein are the signature compounds of CHINESE skullcap; American skullcap's own profile is dominated by scutellarin and baicalin in different proportions, and the two plants are routinely conflated in the mechanism literature.
Thin evidence sitting on top of a real liver signal, which is the worst combination in this batch. On efficacy: the modern trial the marketing rests on is Brock 2014 (Phytotherapy Research, PMID 23878109), a randomised double blind placebo controlled crossover study of 350 mg of Scutellaria lateriflora three times daily for two weeks in 43 HEALTHY volunteers. It did not meet its anxiety endpoint. There was no significant difference between skullcap and placebo on the Beck Anxiety Inventory (p equal to 0.191), which is unsurprising because 81 percent of the participants were not anxious to begin with. The mood finding that gets quoted is a WITHIN group change from pre test scores, not a clean win over placebo, and a within group change in an unblinded direction is the oldest weak evidence tell there is. One earlier trial (Wolfson 2003) was smaller still. There is no systematic review, no regulatory monograph, and no trial in an actually anxious population. That is insufficient. On safety, this ingredient is not a neutral herb. NIH LiverTox assigns American skullcap likelihood score B, very likely but rare cause of clinically apparent liver injury, which is a higher grade of certainty than valerian (C) or saw palmetto (D) carry. LiverTox records that some cases have resulted in acute liver failure, and describes a 28 year old man who progressed to liver failure and liver transplant 5 weeks later, dying shortly thereafter. Injury usually appears in MULTI BOTANICAL products, which is exactly how skullcap is normally sold, and LiverTox notes that phytochemical analysis has in some cases identified significant adulterants (germander, itself a known liver toxin) or mislabelling in suspected skullcap hepatotoxicity, so part of the risk is supply chain risk. Two different plants share this name: American skullcap (Scutellaria lateriflora) and Chinese skullcap (Scutellaria baicalensis, huang qin). They are not interchangeable. LiverTox notes the Chinese species is a different species that may also have adverse effects on the liver, with injury resembling that associated with the North American plant. Whichever one is in the bottle, the liver question does not go away.
The only well described human dose is the one used in Brock 2014: 350 mg of dried aerial parts, three times daily, for two weeks. That dose did not beat placebo on anxiety, so it is a studied dose, not an effective one. No authority has established a standard dose.
Tincture: 2 to 4 ml three times daily. Tea: 1 to 2 tsp dried herb per cup, up to 3 times daily.
Reports of hepatotoxicity historically linked to misidentification with germander, use reputable suppliers.
Pregnancy: avoid
Breastfeeding: avoid
Active compounds: baicalin, baicalein, scutellarin, wogonin
Remedies using Skullcap · Browse by body system · Check it against what you take
*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.