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Active Half-life of Steroids and Esters

Updated by PartyBoy, MuscleTalk Moderator

An important consideration when planning a steroid cycle, in particular the timing of dosing to be administered, is the active half-life of the drug being employed. The half-life may be defined as the time (t) the level is half of the starting level of a given compound; at time 2t, the level is a quarter of the starting level, and at time 3t, the level is an eighth of the starting level, and so on.

This information is vital in the timing of the dosing when attempting to achieve a more stable blood concentration, which leads to greater overall results and maintenance of gains. Some fluctuations of concentration levels are acceptable, and are also mostly unavoidable, but should be kept to a minimum.

This article covers the half-life’s of the most commonly used steroids, esters and ancillary compounds.

Oral steroids

DrugActive half-life
Anadrol / Anapolan50 (oxymetholone)8 to 9 hours
Anavar (oxandrolone)9 hours
Dianabol (methandrostenolone, methandienone)4.5 to 6 hours
Methyltestosterone4 days
Winstrol (stanozolol)
(tablets or depot taken orally)
9 hours

Steroid esters

The half-life applies to the ester regardless of hormone attached, for example trenbolone enanthate and primobolan (methenolone enanthate) will act very similarly to testosterone enanthate in terms of release rate.

Drug Active half-life
Suspension within 1 hour
Acetate 1 day
Propionate 1 day
Phenylpropionate 1-2 days
Butyrate 2-3 days
Valerate 3 days
Hexanoate 3 days
Caproate 4-5 days
Isocaproate 4-5 days
Heptanoate 5-6 days
Enanthate 5-6 days
Octanoate 6-7 days
Cypionate 6-7 days
Nonanoate 7 days
Decanoate 7-8 days
Undeclenate 8-9 days
Undecanoate Approx 20 days


Drug Active half-life
Arimidex 3 days
Clenbuterol 1.5 days
Clomid 5 days
Cytadren 6 hours
Ephedrine 6 hours
T3 10 hours

A practical example is if one was to inject 100mg of testosterone propionate and allow blood levels to peak. In approx 36 hours time (half-life duration from the above tables) and providing no other injections had taken place, the level would be reduced to 50mg. Again, a further approx 36 hours down the line and levels would have dropped to 25mg, and the value keeps halving every approx 36 hours.

Warning! Articles related to the use of illegal performance enhancing drugs are for information purposes only and are the sole expressions of the individual authors opinion. We do not promote the use of these substances and the information contained within this publication is not intended to persuade or encourage the use or possession of illegal substances. These substances should be used only under the advice and supervision of a qualified, licensed physician.

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