Anyone new to steroids may be wondering what this means, even some experienced steroid users may also be wondering what this means. So here in simple terms you can read and hopefully understand all about steroid half life's and what this term means.
Basically every drug has a half life, steroids included. If for example, you were to inject 1000mg of testosterone cypionate once weekly, for 10 weeks, how would you know when you were "off"? Would you be "off" when you had finished your last dose? You would be able to calculate this from the half life of testosterone cypionate. The half life of testosterone cypionate is around 12 days. This means that 12 days from your last shot of 1000mg of testosterone cypionate (Time to start PCT? You decide.), your blood levels of testosterone cypionate will contain 500mg of the steroid. Another 12 days from then, i.e. 24 days from last dose, your blood levels will contain 250mg of the steroid. This amount then keeps halving every 12 days. At 48 days (almost 2 months) from your last dose, your blood levels will still contain 67.5mg of testosterone cypionate.
Therefore you can clearly see that when you finish your cycle, even though you are not putting any steroids into your body, you may think that you are now "off", however you still have, and will still have for some time after your last dose, "active" blood levels of the steroid. Therefore you can plan what to use, how long for, and how long off your cycle, based on these half life's.
Below a list of half-life's of the most commonly used steroids, esters and ancillary compounds.
Oral steroids (Anabolic Steroids - Steroid .com) Drug Active half-life
Anadrol / Anapolan50 (oxymetholone) 8 to 9 hours
Anavar (oxandrolone) 9 hours
Dianabol (methandrostenolone, methandienone) 4.5 to 6 hours
(tablets or depot taken orally) 9 hours
Steroid esters Drug Active half-life
Formate 1.5 days
Acetate 3 days
Propionate 2 days
Phenylpropionate 4.5 days
Butyrate 6 days
Valerate 7.5 days
Hexanoate 9 days
Caproate 9 days
Isocaproate 9 days
Heptanoate 10.5 days
Enanthate 10.5 days
Octanoate 12 days
Cypionate 12 days
Nonanoate 13.5 days
Decanoate 15 days
Undecanoate 16.5 days
Ancillaries Drug Active half-life
Arimidex 3 days
Clenbuterol 1.5 days
Clomid 5 days
Cytadren 6 hours
T3 10 hours
Active Life versus Half Life
The confusion comes from the 2 terms being used synonymously when they should not be. "Half-life is not a reference for the total time a drug will be found active in the body. It may take several half-lives before the drug is completely inactive."
Half-life: The period of time required for the concentration or amount of drug in the body to be reduced to exactly one-half of a given concentration or amount.
Active life: Refers to the period in which the amount of a drug in the body is enough that it will still produce the desired effects for which it was administered. Or conversely, inhibit natural recovery of normal bodily function. It is dose dependent.
An ester is a chain composed primarily of carbon and hydrogen atoms. This chain is typically attached to the parent steroid (Anabolic Steroids - Steroid .com) hormone at the 17th carbon position (beta orientation), although some compounds do carry esters at position 3 (for the purposes of this article it is not crucial to understand the exact position of the ester). Esterification of an injectable anabolic (http://www.steroid.com/)/androgenic steroid (Anabolic Steroids - Steroid .com) basically accomplishes one thing, it slows the release of the parent steroid (Anabolic Steroids - Steroid .com) from the site of injection (Steroid Injections - Steroid .com). This happens because the ester will notably lower the water solubility of the steroid (Anabolic Steroids - Steroid .com), and increase its lipid (fat) solubility. This will cause the drug to form a deposit in the muscle tissue, from which it will slowly enter into circulation as it is picked up in small quantities by the blood. Generally, the longer the ester chain, the lower the water solubility of the compound, and the longer it will take to for the full dosage to reach general circulation.
Esterification temporarily deactivates the steroid (Anabolic Steroids - Steroid .com) molecule. With a chain blocking the 17th beta position, binding to the androgen receptor is not possible (it can exert no activity in the body). In order for the compound to become active the ester must therefore first be removed. This automatically occurs once the compound has filtered into blood circulation, where esterase enzymes quickly cleave off (hydrolyze) the ester chain. This will restore the necessary hydroxyl (OH) group at the 17th beta position, enabling the drug to attach to the appropriate receptor. Now and only now will the steroid (Anabolic Steroids - Steroid .com) be able to have an effect on skeletal muscle tissue.
While the advent of esters certainly constitutes an invaluable advance in the field of anabolic (Anabolic Steroids - Steroid .com) steroid medicine, clearly you can see that there is no magic involved here. Esters work in a well-understood and predictable manner, and do not alter the activity of the parent steroid (Anabolic Steroids - Steroid .com) in any way other than to delay its release. Although the lure surrounding various steroid (Anabolic Steroids - Steroid .com) products like testosterone (Testosterone Enanthate - Steroid .com) cypionate, Sustanon, Omnadren etc. certainly makes for interesting conversation, realistically it just amounts to misinformation that the athlete would be better off ignoring. Testosterone is testosterone (Testosterone Enanthate - Steroid .com) and anyone who is going to tell you one ester form of this (or any) hormone is much better than another one should do a little more research, and a lot less talking.
Acetate: Chemical Structure C2H4O2.
Also referred to as Acetic Acid; Ethylic acid; Vinegar acid; vinegar; Methanecarboxylic acid. Acetate esters delay the release of a steroid (Anabolic Steroids - Steroid .com) for only a couple of days. Contrary to what you may have read, acetate esters do not increase the tendency for fat removal. Again, there is no known mechanism for it to do so. It is the steroid (Anabolic Steroids - Steroid .com) and not the ester. This ester is used on oral primobolan (Primobolan - Steroid .com) tablets (metenolone acetate), Finaplix (trenbolone acetate) implant pellets, and occasionally testosterone (Testosterone Enanthate - Steroid .com).
Caproate: Chemical Structure C6H12O2.
Also referred to as Hexanoic acid; hexanoate; n-Caproic Acid; n-Hexoic acid; butylacetic acid; pentiformic acid; pentylformic acid; n-hexylic acid; 1-pentanecarboxylic acid; hexoic acid; 1-hexanoic acid; Hexylic acid; Caproic acid. This ester is identical to isocarpoate in terms of atom count and weight, but is laid out slightly different (Isocaproate has a split configuration, difficult to explain here but easy to see on paper). Release duration would be very similar to isocaproate (levels sustained for approximately one weak), perhaps coming slightly closer to enanthate (Testosterone Enanthate - Steroid .com) due to its straight chain. Caproate is the slowest releasing ester used in Omnadren (Omnadren 250 - Steroid .com), which is why most athletes notice more water retention with this compound due to blood level saturation.
Decanoate: Chemical Structure C10H20O2.
Also referred to as decanoic acid; capric acid; caprinic acid; decylic acid, Nonanecarboxylic acid. The Decanoate ester is most commonly used with the hormone nandrolone (Deca-Durabolin - Steroid .com) (as in Deca (Deca-Durabolin - Steroid .com) and is found in virtually all corners of the world. Testosterone decanoate is also the longest acting constituent in Sustanon (Sustanon 250 - Steroid .com), greatly extending its release duration. The release time with Decanoate compounds is listed to be as long as one month, although most recently we are finding that levels seem to drop significantly after two weeks. To keep blood levels more uniform, athletes (as they have always known to do) will follow a weekly injection (Steroid Injections - Steroid .com) schedule.
Undecylenate: Chemical Structure C11H20O2.
Also referred to as Undecylenic acid; Hendecenoic acid; Undecenoic acid. This ester is very similar to decanoate, containing only one carbon atom more. Its release duration is likewise very similar (approximately 2-3 weeks), perhaps extending a day or so past that seen with decanoate. Undecylenate seems to be exclusive to the veterinary preparation Equipoise (Equipoise - Steroid .com) (boldenone undecylenate), although there is no reason it would not work well in human-use preparations (Equipoise certainly works fine for athletes). Again, weekly injections (Steroid Injections - Steroid .com) are most common.
Undecanoate: Chemical Structure C11H22O2.
Also referred to as Undecanoic Acid; 1-Decanecarboxylic acid; Hendecanoic acid; Undecylic acid. Undecanoate is not a commonly found ester, and only appears to be used in the nandrolone (Deca-Durabolin - Steroid .com) preparation Dynabolan (Dynabolan - Steroid .com), and oral testosterone (Testosterone Enanthate - Steroid .com) undecanoate (Andriol). Since this ester is chemically very similar to undecylenate (it is only 2 hydrogen atoms larger), it has a similar release duration (approximately 2-3 weeks). Although this ester is used in the oral preparation Andriol (Andriol - Steroid .com), there is no reason to believe it carries any properties unique of other esters. Andriol in fact works very poorly at delivering testosterone (Testosterone Enanthate - Steroid .com), bolstering the idea that oral administration is not the idea use of esterified androgens.
Laurate: Chemical structure C12H24O2.
Also referred to as Dodecanoic acid, laurostearic acid, duodecyclic acid, 1-undecanecarboxylic acid, and dodecoic acid. Laurate is the longest releasing ester used in commercial steroid (Anabolic Steroids - Steroid .com) production, although longer acting esters do exist. Its release duration would be closer to one month than the other esters listed above, although realistically we are probably to expect a notable drop in hormone level after the third week. Laurate is exclusively found in the veterinary nandrolone (Deca-Durabolin - Steroid .com) preparation Laurabolin (Laurabolin - Steroid .com), perhaps seen as slightly advantageous over a decanoate ester due to a less frequent injection (Steroid Injections - Steroid .com) schedule. Again athletes will most commonly inject (Steroid Injections - Steroid .com) this drug weekly, no doubt in part due to its low strength (25mg/ml or 50mg/ml).
All the evidence points to the use of short estered AAS injectables, versus long estered AAS injectables, as being the fastest way to recover natural testosterone levels post cycle.
*Note: The information above was compiled from a number of different authors and websites.
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