Question 1

How does psoralea seed work for vitiligo?

Accepted Answer

Psoralea seed contains psoralen and isopsoralen, photosensitizing compounds that stimulate melanocyte activity when exposed to ultraviolet light. These furanocoumarins bind to DNA and promote melanin production in depigmented skin areas. This mechanism underlies its use in PUVA (psoralen plus UVA) therapy for vitiligo. The herb also contains bakuchiol, which has demonstrated antioxidant and anti-inflammatory properties that may support skin healing. Evidence level: C (preliminary clinical evidence supports use combined with UV exposure).

Question 2

Does psoralea seed interact with medications?

Accepted Answer

Psoralea seed may interact with photosensitizing medications, including certain antibiotics (tetracyclines, fluoroquinolones), thiazide diuretics, and retinoids, potentially increasing photosensitivity reactions. It may affect cytochrome P450 enzyme activity, altering metabolism of various pharmaceuticals. Due to potential hepatotoxicity, it should not be combined with other liver-stressing medications. Patients taking immunosuppressants should use caution. Always consult a healthcare provider before combining with prescription medications. Evidence level: C (theoretical interactions based on pharmacological data).

Question 3

What is the recommended dosage for psoralea seed?

Accepted Answer

In Traditional Chinese Medicine, the standard adult dosage is 6-12 grams of dried seeds daily, typically decocted as a tea or taken in powder form. For standardized psoralen extracts used in vitiligo treatment, doses typically range from 40-80mg of psoralen content daily, always combined with controlled UV exposure. Dosage should be individualized based on condition severity and treatment goals. Professional guidance is recommended, as improper dosing increases photosensitivity risks. Evidence level: Traditional/Expert opinion.

Question 4

Is psoralea seed safe during pregnancy?

Accepted Answer

Psoralea seed is contraindicated during pregnancy and breastfeeding. The psoralen content poses potential risks to fetal development, and the herb's effects on uterine tissue have not been adequately studied for safety. Traditional sources and modern safety assessments classify it as unsafe for pregnant individuals. Additionally, photosensitizing properties could pose unpredictable risks during pregnancy when skin sensitivity may already be heightened. Women who are pregnant, planning pregnancy, or breastfeeding should avoid this herb entirely. Evidence level: C/D (traditional contraindication with limited modern safety data).

Question 5

What are the side effects of psoralea seed?

Accepted Answer

Common side effects include photosensitivity reactions, which can cause skin redness, blistering, or hyperpigmentation when exposed to sunlight or UV light. Gastrointestinal upset, including nausea and stomach discomfort, may occur with oral use. In rare cases, liver toxicity has been reported with prolonged high-dose use. Discontinue use if severe skin reactions, jaundice, or persistent digestive symptoms develop. Those with pre-existing liver conditions or photosensitivity disorders should exercise particular caution. Evidence level: C (based on clinical observations and case reports).

Question 6

What is psoralea seed used for in TCM?

Accepted Answer

In Traditional Chinese Medicine, psoralea seed (Bu Gu Zhi) is classified as a kidney yang tonic. It is traditionally used to warm the kidney and spleen, strengthen bones and teeth, and treat conditions associated with kidney yang deficiency including lower back pain, knee weakness, urinary frequency, and impotence. Its most well-documented modern application is treating vitiligo through its psoralen content. The herb is considered warming and drying in nature, making it unsuitable for those with yin deficiency or excess heat patterns. Evidence level: Traditional use with Level C clinical support for vitiligo.

Psoralea Seed

Sources & Citations

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Drug interactions

Evidence summary

PubMed sources

Government sources