Apigenin

Human sleep evidence relates to whole chamomile extract rather than isolated apigenin. A randomised, double-blind, placebo-controlled pilot trial enrolled 34 adults aged 18 to 65 with primary insomnia lasting at least 6 months and gave 270 mg of standardised chamomile extract twice daily or placebo for 28 days. There were no significant differences between groups in any sleep-diary measure, including total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sleep quality and number of awakenings. Effect sizes were small to moderate (Cohen's d from 0.20 to under 0.60): moderate effects favoured chamomile for sleep latency, night-time awakenings and fatigue, while a moderate effect favoured placebo for total sleep time. Daytime functioning showed a modest advantage for chamomile that did not reach statistical significance, and adverse events did not differ between groups [2].

The case for apigenin rests on receptor-binding assays and mouse behaviour [1]. Chamomile extract contains many compounds besides apigenin, so the chamomile trial cannot separate apigenin's contribution, and as a 34-person pilot it was not powered to detect small effects [2]. No randomised trial of isolated apigenin for sleep is among the sources cited here, which makes it the entry with the weakest human evidence relative to its mechanistic rationale.

The chamomile trial used 270 mg of extract twice daily for 28 days; each 90 mg capsule was standardised to at least 2.5 mg of apigenin, and laboratory analysis found 3.9 mg of apigenin per 90 mg of extract [2].