Calculators

Half-life calculators by compound

Pick a compound to calculate its buildup in the body for your own dose and schedule. The math is a standard exponential-decay model — for reference only, not a substitute for bloodwork.

Testosterone

Testosterone Enanthate A mid-speed ester: it peaks roughly 24-48 hours after injection, then declines gradually. Typically dosed once every 5-7 days. Open calculator →Testosterone Cypionate Close in speed to enanthate, just slightly slower — hence a marginally longer time to the next peak. More common in the US market. Open calculator →Testosterone Propionate The fastest of the common testosterone esters: it peaks and clears within 2-3 days, so it's usually injected more often — typically every other day. Open calculator →

Other injectables

Nandrolone Decanoate (Deca) One of the longest-acting esters here: a half-life around 8-9 days, so levels build up slowly and linger long after the last shot. Open calculator →Trenbolone Acetate A fast ester with a half-life around 2-3 days, so it's dosed often — every other day or daily — to avoid sharp swings in level. Open calculator →Trenbolone Enanthate A longer-acting trenbolone ester: injected less often (usually weekly), but it also takes longer to reach a stable plateau. Open calculator →Boldenone Undecylenate (Equipoise) One of the longest esters on this list: a half-life around two weeks, so levels rise and fall very gradually. Open calculator →Drostanolone Propionate (Masteron P) A fast ester, like testosterone propionate: a 2-3 day half-life, usually dosed every other day. Open calculator →

PCT

Clomiphene (Clomid) Not an ester — an oral PCT medication with a half-life around 5 days, taken daily over a short course. Open calculator →Tamoxifen (Nolvadex) An oral PCT medication with a half-life around a week for the parent compound, while its active metabolite lingers even longer. Open calculator →