Note: Once injected into your body, ester chains are enzymatically removed before the steroid can bind to androgen receptors. The amount of active steroid differs among esterified forms due to the ester’s length and weight.

Before the advent of esterified forms of steroid hormones, testosterone suspension–a water-based solution–was the primary method for delivering testosterone into the body. This form of testosterone, lacking any ester attachment, has a very short half-life in the bloodstream, necessitating injections every few hours to maintain effective levels for therapeutic or performance-enhancing effects. The frequent dosing schedule was not only inconvenient but also made it challenging to maintain stable blood testosterone levels, leading to fluctuating hormone levels that could affect mood, energy, and overall effectiveness of the treatment. The development of esterified forms of testosterone, such as testosterone propionate, enanthate, and cypionate, marked a significant advancement. These forms release testosterone gradually over time, allowing for less frequent injections, more stable hormone levels, and improved patient compliance. The innovation of esterification essentially revolutionized testosterone therapy and steroid use, providing a more practical and manageable approach to hormone replacement therapies and performance enhancement strategies.

Note: Ester chains in injectable steroids affect the release rate and solubility of the steroid in the body but do not contribute to muscle building. They are enzymatically removed before the steroid can activate androgen receptors. Different esters have varying half-lives and occupy a certain percentage of the total steroid weight, affecting the actual amount of active steroid. For example, propionate has a shorter half-life and takes up less weight than enanthate, leading to differences in the total testosterone available.

How many ester chains are there?

Below, you can find a list of the most widely used ester chains for delivering anabolic steroids.

Acetate: Molecular Formula C2H4O2

Commonly known as ethanoic acid, acetic Acid, Acid of vinegar, ethylic Acid, and methanecarboxylic Acid, acetate derivatives prolong the action of steroids for a brief period, typically a few days. Despite misconceptions, no evidence suggests acetate forms enhance fat loss capabilities. Their mechanism does not facilitate fat reduction. This ester is incorporated in oral Primobolan (methenolone acetate), Finaplix (trenbolone acetate) pellets, and sometimes in testosterone variations.

Propionate: Molecular Formula C3H6O2.

Also known are hydroacrylic acid, ethylformic Acid, methylethanoic Acid, Carboxyethane, ethylene-carboxylic acid, Metacetonic Acid, and Propionic Acid. Propionate esters decelerate the release of steroids, maintaining serum levels for several days. Frequent injections, typically two to three times a week, are necessary to stabilize blood concentrations. Testosterone propionate and methandriol dipropionate (comprising two propionate esters linked to methandriol) are among the favored choices.

Phenylpropionate: Molecular Formula C9H10O2.

Known as Propionic acid Phenyl Ester. Phenylpropionate extends the active steroid’s release marginally longer than propionate, necessitating at least biweekly injections to maintain consistent blood levels. Nandrolone phenylpropionate(NPP), is the most commonly associated drug with this ester. However, it’s also utilized in testosterone mixtures such as Sustanon and Omnadren.

Isocaproate: Molecular Formula C6H12O2.

Identified as isocaproic acid, 4-methyl valeric acid, isohexanoate. Isocaproate’s release timeline closely mirrors enanthate’s, though it’s somewhat shorter, maintaining hormone levels for about a week. This ester is present in mixed testosterone products like Sustanon and Omnadren.

Caproate: Molecular Formula C6H12O2.

Also known as Hexanoic Acid, Hexanoate, n-hexoic Acid, Butylacetic Acid, Pentylformic Acid, and 1-Pentanecarboxylic Acid. Caproate shares a similar molecular structure and mass with isocaproate. Still, it differs in configuration, which is not easily described but observable in structural diagrams. Its release profile is akin to isocaproate, with hormone levels sustained for around one week, closely approaching enanthate due to its linear chain. Caproate is notably present in Omnadren, contributing to higher water retention observed by athletes due to this compound.