Skullcap Extract
Also known as: Scutellaria lateriflora L., Scutellaria baicalensis, American Skullcap, Chinese Skullcap, Baikal Skullcap, Scutellaria lateriflora
Overview
Skullcap refers to the dried leaves and stems of plants from the *Scutellaria* genus, primarily *Scutellaria lateriflora* (American Skullcap) and *Scutellaria baicalensis* (Chinese Skullcap). It is available in various forms, including capsules, teas, fluid extracts, and tinctures, and has been traditionally used to alleviate anxiety, stress, and insomnia. The herb is characterized by its anxiolytic, antioxidant, and anti-inflammatory properties, attributed to active compounds like flavonoids such as wogonin and baicalein. While research on Skullcap is ongoing, it is considered to be at a moderate stage, with several case reports, observational studies, and some preclinical studies available. However, there is a need for more extensive randomized controlled trials (RCTs) to definitively establish its efficacy and safety. The current evidence is largely based on case reports and systematic reviews focusing on herb-induced liver injury, which limits confidence in its therapeutic benefits and overall safety profile.
Benefits
Skullcap is often promoted for its potential anxiolytic and stress-relieving effects. Preclinical studies suggest antioxidant and anti-inflammatory properties, which may contribute to these effects. Some research indicates that Skullcap extracts may inhibit TH2-mediated responses and induce apoptosis in cancer cells, but these findings are preliminary and require confirmation through human trials. While Skullcap is used in herbal preparations for general health and wellness, particularly for anxiety and stress relief, robust evidence supporting population-specific benefits is lacking. Due to the scarcity of RCTs, the effect sizes and clinical significance of Skullcap are not well established, with most studies focusing on its potential hepatotoxicity rather than therapeutic efficacy. The time course of benefits is also not clearly defined due to the absence of longitudinal studies.
How it works
Skullcap extracts, particularly flavonoids like wogonin and baicalein, interact with various biological pathways, including antioxidant and anti-inflammatory pathways. These compounds may modulate neurotransmitter activity and immune responses. Skullcap may interact with the central nervous system to produce anxiolytic effects and with the immune system to modulate inflammatory responses. The active compounds in Skullcap target various molecular pathways, including those involved in oxidative stress and inflammation. Wogonin, for example, has been shown to induce apoptosis in cancer cells through a mitochondrial-mediated pathway. The absorption and bioavailability of Skullcap extracts are not well studied, but preclinical data suggest that the bioactive compounds can be absorbed and exert biological effects, but human pharmacokinetic studies are lacking.
Side effects
Skullcap has been associated with liver injury, particularly hepatocellular and mixed hepatocellular-cholestatic patterns. The severity can range from mild to severe, with a significant mortality rate in some cases. Common symptoms reported in cases of Skullcap-induced liver injury include nausea and choluria. Autoimmune hepatitis and other severe liver injuries have been reported, although these are less common. In severe cases, liver transplantation may be necessary due to acute liver failure. Skullcap may interact with other herbal supplements and medications, particularly those affecting the liver. Skullcap is not recommended for children, and its use should be cautious in individuals with pre-existing liver conditions or those taking other hepatotoxic substances. Females and individuals with a mean age of 54 years are more commonly affected by Skullcap-induced liver injury. Patients with osteoarthritis and hypertension also frequently report adverse effects.
Dosage
There is no established minimum effective dose of Skullcap due to the lack of standardized clinical trials. Doses in case reports range from 400 mg to 16 g daily. Optimal dosage ranges are not well defined, and users should consult with a physician to determine the appropriate form and dose based on individual needs. The maximum safe dose is not established, but high doses have been associated with an increased risk of liver injury. There are no specific timing considerations established, but monitoring for liver function is recommended, especially with long-term use. Skullcap is available in various forms, including capsules, teas, fluid extracts, and tinctures. The choice of form should be guided by a healthcare professional. Absorption factors are not well studied, but bioactive compounds are known to be absorbed and exert biological effects. There are no established cofactors required for the efficacy of Skullcap extracts.
FAQs
Is Skullcap safe to use?
Skullcap can cause liver injury, and users should be aware of the potential risks, especially if they have pre-existing liver conditions or are taking other hepatotoxic substances.
When is the best time to take Skullcap?
There is no specific timing recommended for Skullcap, but users should monitor their liver function regularly, especially with long-term use.
What are the expected results from taking Skullcap?
The expected results in terms of therapeutic benefits are not well established due to the lack of robust clinical trials. However, users may experience anxiolytic effects based on preclinical data.
Are herbal supplements always safe?
A common misconception is that herbal supplements are always safe. Skullcap, like other herbal supplements, can have significant adverse effects, particularly on the liver.
Research Sources
- https://f6publishing.blob.core.windows.net/60b36e01-49d1-4716-9398-22bc70511eb4/WJH-16-120.pdf – This systematic review and meta-analysis examined 936 cases of herb-induced liver injury (HILI) associated with 79 herbs, including Skullcap. The study found that Skullcap-induced HILI often presented with hepatocellular patterns and mild-to-moderate severity, with a significant mortality rate of 14.2% and a need for liver transplantation in severe cases, highlighting the importance of recognizing potential adverse events associated with herbal dietary supplements.
- https://www.mountsinai.org/health-library/herb/skullcap – This resource provides general information about Skullcap, including its traditional uses for anxiety, stress, and insomnia. It also notes that Skullcap is available in various forms and should be used with caution, especially in individuals with pre-existing liver conditions.
- https://www.ncbi.nlm.nih.gov/books/NBK548757/ – This entry from LiverTox discusses the potential hepatotoxicity of Skullcap, noting that it has been linked to cases of liver injury with hepatocellular and mixed patterns. It emphasizes the importance of considering Skullcap as a potential cause of liver injury, especially in patients using herbal supplements.
- https://www.mdpi.com/1420-3049/29/17/4153 – This preclinical study explores the antioxidant, anti-inflammatory, and anticonvulsant activities of Skullcap extracts, particularly wogonin, using in vitro and animal models. While the findings suggest potential mechanisms of action, the study emphasizes the need for human trials to confirm efficacy and safety.
