Eastbound Jet Lag (5+ zones)

A Cochrane review concluded that melatonin is effective for preventing and reducing jet lag, with the largest effect in eastbound travel and across 5+ time zones. The phase-shifting effect is hormonal, not sedative — and counterintuitively, low doses (0.3-0.5 mg) produce a cleaner shift than high doses (3-10 mg). High doses elevate plasma melatonin far above physiological levels and can blunt the circadian signal as well as cause next-day grogginess. Take 30 minutes before your target local bedtime in the destination time zone, not your origin bedtime.^{[1, 2, 3]}

Magnesium is an NMDA receptor antagonist and GABA-A receptor agonist, which together promote nervous system relaxation. The glycinate form is well-absorbed and well-tolerated and pairs with the calming glycine carrier. Particularly useful when sleep is disrupted by an unfamiliar environment, late dinner, or the residual stress of travel.^{[4, 5]}

Glycine lowers core body temperature by increasing peripheral blood flow — the same signal that normally precedes sleep onset. Small trials in adults with subjective sleep complaints found 3 g of glycine reduced sleep latency and improved next-day subjective alertness compared with placebo. Particularly helpful if you arrive at your destination physically stimulated and have trouble winding down.^{[6, 7, 8]}