No optimal dosages or durations for kava consumption have been determined at this point.^[8] Kava dosing, especially in standardized formulations, may be done with reference to the kavalactone (specifically, kavapyrone; all known kavalactones are pyrones) content. Clinical trials have used dosages ranging from 100 to 400 mg/day of kava, and from 60 to 630 mg of kavalactones, per day.^{[9][10][11][12][13]}

As with any plant or herbal preparation, factors such as plant part, growth conditions, and extraction methods may affect the bioactivity of kava supplements. Ideally, supplements will identify a standardized kavalactone content to improve consistency of results.^{[14][15][16][17][18][19]} There appears to be some potential for substance abuse of kava, but when it is taken at the more commonly seen dosages, this is rare.^[20]

Some of kava’s active ingredients may be secreted in breast milk. Since the effects of kava in infants are still not known, use of kava while pregnant or breastfeeding is not advised.^[21]

Kava may also interact with other substances like alcohol and St. John’s wort, possibly amplifying both positive and negative effects.^{[22][23][24][25]} Reports of these interactions are varied, though, and may depend on circumstances such as dose, timing, format, and external factors.^[26][27] Therefore, combination therapies that include kava should be considered with caution.