Side by side, from the same cited data as each monograph: the best-graded human outcomes, studied doses, intake limits and published interactions. It compares the research, not products, and says nothing about taking the two together.
Ashwagandha (Withania somnifera) is an Ayurvedic herb sold as root or root-and-leaf extracts standardized to withanolides.
Botanical · Stress, Sleep, Performance
Top graded outcomes (6 total)
B evidence gradePerceived stress↑Improved · meta-analysis · n = 1,002 · ashwagandha extracts (various)
B evidence gradeOverall sleep↑Improved · meta-analysis · n = 400 · ashwagandha extract (root, or root-and-leaf in one trial)
C evidence gradeAnxiety scores (HAM-A)↑Improved · meta-analysis · n = 254 · Withania somnifera extracts
C evidence gradeMorning cortisol↑Improved · RCT · n = 60 · root-and-leaf extract (Shoden)
Studied doses
Doses studied in human trials ranged from 120 to 1,250 mg/day of standardized extract, for 6 to about 13 weeks. One trial gave 12 g/day of root granules, equivalent to 6 g of root powder. Extracts differ in plant part and withanolide content, so amounts are not interchangeable.
Intake reference: No RDA, AI or UL exists for ashwagandha. ODS notes it is hard to define amounts because trials used different extracts and doses.
Doses studied in human trials ranged from 600 to 1,000 mg/day of berberine in the trials graded here, usually split into two or three doses, for 2 weeks to 3 months; lipid trials pooled in one meta-analysis lasted 4 to 24 weeks. Dihydroberberine has been studied only at 100–200 mg servings in a one-day pilot.
Published interactions
Drugs cleared by CYP2D6, CYP2C9 or CYP3A4; Cyclosporine
Who should be careful
Pregnancy, breastfeeding and infants; People taking prescription medicines; Diabetes medicines; Digestive side effects; Before you start
