Esters of Testosterone and Its Derivatives
Ether is a carboxylic acid residue attached to the alcohol group of an anabolic steroid molecule in order to give it the necessary pharmacological properties: deposition and slow release into the blood.
Most anabolic steroids are destroyed very quickly in the body, for example, the introduction of pure testosterone requires daily injections. For convenience, depot preparations were invented, which are an "anabolic + ether" complex dissolved in oil. Esters are readily soluble in oil and poorly in water, however, if an oil solution is dropped into water, the "anabolic + ether" molecules will very slowly pass from oil to water.
At the injection site (usually inside the muscle), an oil depot is formed, from which the drug is released into the bloodstream. The rate of transition of a steroid into the blood is characterized by the half-life of its ether. The half-life (or half-life or half-life) is the time during which the concentration of ether in the blood after 1 injection will decrease by exactly 50% (half of the drug is excreted from the body). There are many different types of ether, differing from each other only in the half-life.
- Longer esters dissolve better in oil due to their high lipophilicity, enter the bloodstream more slowly, and have a longer half-life.
- The duration of action is approximately two half-lives. Thus, the longer the ester chain, the longer the duration of the drug's action.
Esters do not have any effect on the properties of the steroid, except for the duration of action.
Types of ethers
Consider the most commonly used testosterone esters and its derivatives in bodybuilding.
Acetate – Has the smallest half-life, equal to about 1 day. With this ester, the most commonly used steroids are trenbolone and primobolan. In addition, testosterone acetate is included in the popular SP-Labs five-ester blend of testosterone esters.
Propionate – One of the most famous esters thanks to the common intake of testosterone propionate by bodybuilders. In addition, the most common uses of propionate are drostanolone propionate (masteron) and methandriol di-propionate. Has a half-life ranging from one to two days.
Phenylpropionate – Nandrolone Phenylpropionate is best known on the basis of this ester. Testosterone Phenylpropionate is also available. Also used in testosterone blends such as Sustanon, omnadren, etc. Half-life is 2 - 3 days.
Isocaproate (isohexanoate) – It is part of Sustanon and omnadren along with other testosterone esters. The half-life is 4 - 5 days.
Enanthate – One of the most commonly used ethers. Used with testosterone, trenbolone, methenolone and other drugs. Has a half-life of 5-7 days.
Hexa-hydro benzyl carbonate or cyclo-hexyl methyl carbonate (synonyms: cyclo-hexyl-methyl-carbonate, hexa-hydro-benzyl-carbonic or hexa-hydro-benzyl carbonate). The chain has 8 carbon atoms, although the erroneous indication of 7 atoms is often found, the half-life according to various sources is about 6-8 days, with properties similar to enanthate. Found in trenbolone (Parabolan). The names differ due to the use of different nomenclatures.
Cypionate – Practically interchangeable with Enanthate. The most common in the United States, although it is quite common here in the form of testosterone Cypionate and nandrolone. Half-life up to 7 days.
Decanoate – Nandrolone Decanoate immediately comes to mind, although it is also part of Sustanon, as the ether with the longest duration in it. The half-life according to various sources is 7 - 9 days. To maintain a constant blood level, injections are given on average once a week. Previously marketed as a standalone product under the brand name Neotest 250 (Loffler), but is no longer available.
Undecylenate – Has a half-life of 9 to 11 days. Among the most famous uses is Boldenone Undecylenate.
Laurate – Half-life 10 - 12 days. The longest-playing ether used in bodybuilding. Of the applications - nandrolone laurate.
There are still many types of ether, but they are practically not used in bodybuilding or are used quite rarely, therefore they were not included in this article.
The mechanism of action of all these esters on the body is well understood and, apart from the time of absorption of the steroid into the bloodstream, it does not affect any other characteristics of the action of this steroid.
Due to the overlapping meaning of pharmacological terms, there is often disagreement about the half-life of various esters. There are two different concepts:
- The half-life or half-life (T1 / 2) - the time required to halve the concentration of the drug in the blood, depends on the rate constant of elimination (T1 / 2 = 0.693 / Kel) and absorption, as a limiting factor. It is this indicator that is important for calculations associated with building a course and conducting post-cycle therapy.
- The half-absorption period (T1 / 2, a) - the time required for the absorption of half the dose of the drug from the injection site into the blood, is proportional to the absorption rate constant (T1 / 2, a = 0.693 / Kel). The pharmacokinetics of essential drugs proceeds according to the “flip-flop” type, therefore the half-absorption index also characterizes the time required to destroy half of the administered dose of the drug, and therefore confusion arises.
Simply put, half-life reflects the concentration of a drug in the blood, and half-absorption indicates the remaining amount of this drug in the body.
Example: after injection of 100 mg nandrolone Decanoate, the concentration of the drug will drop by half after 7 days, after another 7 days by four times, etc., while 50% of the drug will be destroyed only after 14-15 days. Formally, the effect of the drug ends after 4 half-lives, when approximately 5% concentration remains.
Most often, there are charts for the half-absorption of esters on the network, which must be divided by 2 in order to obtain the half-life, which characterizes the concentration of the anabolic in the blood. The following are the blood half-lives for anabolic drugs taken from various scientific sources:
- Acetate – 1 day;
- Propionate – 1-2 days;
- Phenylpropionate – 2 days;
- Hexanoate – 3-4 days;
- Caproat – 4-5 days;
- Isocaproate – 4-5 days;
- Enanthate – 5-6 days;
- Hexahydrobenzyl carbonate (cyclohexylmethyl carbonate) – 6-7 days;
- Cypionate – 6-7 days;
- Decanoate – 7-8 days;
- Undecanoate – 8 days;
- Undecylenate – 8-9 days;
- Laurate – 10 days.
Injections into the deltoid muscle instead of the gluteal muscle slows down excretion. The type of solvent oil also plays a significant role. Research has shown that as the carbon chain lengthens, anabolic activity increases and androgenic activity decreases.
Anabolic drugs can only be used as directed by a doctor and are contraindicated in children. The information provided does not call for the use or distribution of potent substances and is solely aimed at reducing the risk of complications and side effects.