Draft content — pending editorial and medical review.
What half-life means
is the time it takes for the amount in the blood to fall by half. After one half-life, 50% remains; after two, 25%; after five, about 3%.
1 half-life
50%2
25%3
12.5%5
≈3%After about five half-lives, a compound is considered largely cleared.
Two examples from the library
Ipamorelin has a of about two hours in humans, which is why studies and community reports describe dosing one to three times a day.
Semaglutide has a half-life of about seven days, so it is given once a week, and takes four to five weeks to reach a steady level.
Timing
Some compounds are studied at particular times — for example, growth-hormone before sleep, when natural GH release peaks. Timing in a study is a design choice; it is not always tested against alternatives.
Common mistakes
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Assuming longer is stronger. A long changes frequency, not necessarily effect.
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Forgetting the build-up. Long half-life compounds accumulate for weeks before levels settle.
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Planning a washout that is too short. Allow several half-lives before comparing on and off.