On this page
Jet lag advice that does not specify the direction of travel is close to useless, because the two directions require opposite interventions.
Why direction matters
The human circadian period runs slightly longer than twenty-four hours, which makes it easier to delay than to advance. Westward travel requires delaying the clock, which aligns with the natural tendency and is generally better tolerated. Eastward travel requires advancing, which fights it. The commonly cited rough guide is around a day of adjustment per time zone crossed for eastward travel and somewhat faster for westward.
Using light correctly
For eastward travel, seek morning light at the destination and avoid evening light, to advance the clock. For westward travel, seek evening light and avoid early morning light, to delay it. The complication is that for large eastward shifts, morning light at destination may fall before your body's temperature minimum, which would delay rather than advance - which is why for shifts beyond about eight hours, some advice reverses or recommends treating it as a westward shift.
The Cognizil discount is applied automatically by quantity — there is no code to enter.
See Cognizil PricingWhat else helps
Shifting your schedule by an hour or two in the direction of travel for a few days before departure reduces the shift needed on arrival. Set your watch to destination time on boarding and eat and sleep on that schedule where feasible. Melatonin timed appropriately has evidence for eastward travel. Caffeine helps acutely but should be avoided within several hours of destination bedtime. Hydration and moving on long flights help general comfort rather than the circadian issue itself.
Key takeaways
- The human circadian period is slightly over twenty-four hours, making delay easier
- Eastward travel needs morning light; westward needs evening light
- For shifts beyond about eight hours the light advice can reverse
- Pre-shifting your schedule before departure reduces the adjustment needed
Where Cognizil fits in
If you are researching supplements in this area, Cognizil is a liquid formula built around six named ingredients — Ginkgo Biloba Leaf, Bacopa Monnieri, St. John’s Wort Extract, N-Acetyl L-Carnitine HCl, Huperzine-A and a Phosphatidylserine Complex. It is labelled for advanced memory support and contains no stimulant. Per-serving amounts are not published, which is a genuine limitation we cover in our label transparency review. The Cognizil official website lists current pricing and guarantee terms.
Cognizil™ — Official Site Pricing
Liquid advanced memory support with Ginkgo Biloba, Bacopa Monnieri, St. John’s Wort, N-Acetyl L-Carnitine, Huperzine-A and Phosphatidylserine. Stimulant-free, taken once daily by dropper.
Check Cognizil AvailabilityFrom $49 per bottle on the 6-bottle tier · free US shipping on 6 bottles · 60-day money-back guaranteeInteraction notice: contains St. John’s Wort. If you take any prescription medicine, including hormonal contraception, check the interaction list and speak to a pharmacist first.