Sleep

An essential mineral involved in over 300 enzymatic reactions. Widely studied for sleep, anxiety, and metabolic health.

Melatonin is an endogenous hormone produced by the pineal gland in response to darkness, serving as the body's primary circadian timing signal. Unlike most supplements, melatonin is a hormone — a distinction with pharmacological and regulatory significance. Its strongest evidence base is in circadian rhythm disorders: jet lag, shift work disorder, and delayed sleep phase syndrome. Its role in improving sleep in otherwise healthy adults without circadian disruption is supported by evidence of modest effect size. A key evidence-informed insight is that commercial doses (5-10mg) are far above the physiological range, and lower doses (0.5mg) appear sufficient for circadian phase shifting with better tolerability. Timing of administration is at least as important as dose.

An amino acid found in green tea. Studied for calm alertness, anxiety reduction, and synergistic effects with caffeine.

Glycine is a conditionally essential amino acid with roles spanning multiple physiological systems: it acts as an inhibitory neurotransmitter in the spinal cord and brainstem, serves as a precursor for glutathione (the body's master antioxidant), is the most abundant amino acid in collagen, and is required for creatine synthesis. Research interest has focused primarily on sleep quality (via a unique core body temperature-lowering mechanism), glutathione support (in combination with NAC), and the hypothesis that modern diets — low in collagen-rich animal parts — may undersupply glycine relative to metabolic demand.

Ashwagandha (Withania somnifera) is a root herb used for centuries in Ayurvedic medicine, classified as an adaptogen for its proposed ability to help the body resist stressors. Its primary bioactive compounds — withanolides — are thought to modulate the hypothalamic-pituitary-adrenal (HPA) axis. Clinical trials using standardized extracts have found evidence for reductions in perceived stress, cortisol, and anxiety, as well as improvements in sleep quality. Some trials also suggest modest support for testosterone and strength in men. Evidence quality is moderate, with most trials being small and short-term; cycling use is recommended given limited long-term safety data.

Taurine is a sulfur-containing compound abundant in muscle, heart, retina, and brain. Unlike most amino acids, it is not incorporated into proteins but plays broad roles in osmoregulation, membrane stabilization, calcium homeostasis, bile acid conjugation, and antioxidant defense. Research interest has historically focused on cardiovascular health and exercise performance. A landmark 2023 paper in Science (Singh et al.) elevated interest in taurine's potential role in aging biology, finding that taurine declines with age and that supplementation extended lifespan in mice — an exciting finding that awaits human interventional replication.