Top 10 Testosterone Based Compounds Explained for Bodybuilders

[MuscleHustle]

Testosterone forms the basis of a great many anabolic-androgenic steroid preparations, but from a pharmacokinetic point of view, steroids based on testosterone are not interchangeable. The ester linked to testosterone can affect the rate at which it is released and eliminated from the body, and testosterone suspensions have no ester at all.

For those individuals who are researching bodybuilding, it is more helpful to understand the differences between these substances than it is just to memorize their compound names. The following guide looks at 10 testosterone-based formulations and esters, concentrating on the features that set them apart, the way they act in the body, and the significant health considerations.

1. Testosterone Base​

The base form of testosterone is testosterone that does not have an ester attached to it; since there is no ester to produce a depot effect, it differs from the more commonly used esterified injectable forms.

Testosterone is the active hormone; esterification does not produce a different anabolic hormone but rather alters the physical and pharmacokinetic characteristics of the formulation.

It is important to make this distinction since talks of 'stronger' testosterone esters can be misleading; the ester mainly affects the way in which testosterone becomes available to the body and does not fundamentally alter the hormone's mechanism of action.

2. Testosterone Suspension​

The testosterone suspension consists of testosterone that is not esterified; unlike testosterone esters that are based on oil, suspension does not depend on the ester being cleaved before testosterone can act.

As a result, suspension has a pharmacokinetic profile which is considerably different from that of the longer-acting testosterone esters; it is thus wrong to regard testosterone suspension as no more than a version of testosterone enanthate or cypionate.

What distinguishes suspension from most of the other injectable testosterone preparations is the fact that it does not contain an ester.

3. Testosterone Propionate​

Testosterone propionate is testosterone to which a propionate ester is attached. When compared with longer-chain esters, the propionate ester results in a formulation that acts more quickly.

One of the reasons why testosterone propionate is often considered separately from longer-acting testosterone preparations is its shorter pharmacokinetic profile.

That does not mean that shorter-acting forms are more anabolic; once testosterone is released, the active hormone is still testosterone.

4. Testosterone Phenylpropionate​

Testosterone phenylpropionate involves attaching testosterone to the phenylpropionate ester and, although it has a longer release profile than testosterone propionate, is usually regarded as a shorter-to-intermediate ester when compared with the very long-acting formulations.

It is also historically significant because phenylpropionate is one of the components of some testosterone ester combinations rather than appearing only in standalone form.

[Image suggestion: Molecular structure of testosterone phenylpropionate]

5. Testosterone Isocaproate​

Testosterone isocaproate is also a form of testosterone that has been converted into an ester. The isocaproate ester affects the way in which testosterone is released from an injectable depot.

This is especially relevant when talking about mixed testosterone formulations since isocaproate can be combined with other testosterone esters to produce a formulation having different release properties.

The main thing is that the ester affects the pharmacokinetics rather than converting testosterone into a completely different hormone.

6. Testosterone Enanthate​

Testosterone enanthate is one of the most well-known of the longer-acting testosterone esters and is used clinically for testosterone replacement as well as being often referred to in bodybuilding literature.

The ester causes testosterone to be released gradually after it has been administered, and clinical guidance identifies testosterone enanthate and cypionate as injectable forms of testosterone whose concentrations increase following administration before decreasing over the dosing period.

Serum testosterone levels can vary after injections, which is why medical treatment involves carrying out laboratory monitoring and making adjustments according to the patient's response.

7. Testosterone Cypionate​

Testosterone cypionate is also a long-acting testosterone ester that is widely acknowledged. As stated in the present DailyMed labeling, testosterone cypionate is slowly absorbed from the lipid phase after intramuscular administration and has a reported intramuscular half-life of about eight days.

The key difference lies in pharmacokinetics and not in anabolic effects. Testosterone cypionate eventually releases testosterone, and it is the cypionate ester that determines the rate at which this hormone becomes available.

When setting an appropriate treatment schedule and keeping an eye on serum testosterone levels, medical testosterone therapy takes account of these characteristics.

8. Testosterone Decanoate​

Testosterone decanoate is a testosterone ester with a longer carbon chain and is less often found as a standalone testosterone product.

Part of its importance lies in the historical and pharmaceutical aspects, since decanoate has been included in combined testosterone preparations, and the longer ester chain causes it to be released more slowly than shorter testosterone esters.

It is therefore useful when talking about testosterone decanoate to distinguish the individual ester from combination products which contain several testosterone esters.

9. Testosterone Undecanoate​

Testosterone undecanoate is an ester of testosterone which has a long duration of action and is available in both oral and injectable forms in various markets.

For example, the injectable drug AVEED contains testosterone undecanoate and results in a gradual release of testosterone when given by intramuscular injection; the prescribing information states that testosterone levels reach their peak at a median of seven days and then decrease slowly.

At steady state, the labeled regimen is intended to keep testosterone levels within the physiological range as a means of treating hypogonadism; this is the reason why pharmaceutical testosterone preparations should not be automatically regarded as being used for bodybuilding.

10. Mixed Testosterone Esters​

Instead of using just one testosterone ester, mixed testosterone formulations combine several different testosterone esters.

A good example is provided by Sustanon-type formulations, which mix together testosterone esters that have different rates of release. The reason for combining the esters is to obtain a formulation having multiple pharmacokinetic phases.

It is necessary to avoid describing a testosterone blend as consisting of a completely different testosterone hormone since the active hormone is still testosterone; the mixture just has testosterone molecules bonded to different ester groups.

How Testosterone Esters Actually Differ​

There is a common misconception that altering the length of the testosterone ester affects the basic anabolic action of testosterone.

It does not.

The ester mainly influences absorption, release, and pharmacokinetics; after the ester has been cleaved, the body is left with testosterone, which is then able to act on androgen receptors and can also be broken down into substances such as dihydrotestosterone and estradiol.

The main practical difference in terms of pharmacology is instead the way in which testosterone levels vary over time.

Testosterone and Natural Hormone Production​

Exogenous testosterone also has an effect on the body's endocrine system, since the administration of external androgens leads to a suppression of pituitary signaling, including that of luteinizing hormone, and greater exposure to androgens results in suppression of follicle-stimulating hormone and spermatogenesis.

Testosterone should not be regarded merely as a substance which builds muscle since it has effects on the reproductive, endocrine, cardiovascular, and metabolic systems.

Testosterone Replacement Therapy vs Bodybuilding Use​

Testosterone replacement therapy is intended for men who have been clinically diagnosed with testosterone deficiency, and the Endocrine Society suggests that hypogonadism should be diagnosed on the basis of symptoms that are compatible with the condition and of consistently low testosterone levels rather than depending on the symptoms alone.

The situation in the medical field is fundamentally different from that concerning the nonmedical use of performance-enhancing drugs. Testosterone therapy prescribed by a doctor includes making a diagnosis, choosing the right form of the medication, carrying out laboratory monitoring, and assessing the risks.

Possible adverse effects may involve the suppression of the body's natural production of testosterone and sperm, changes in hematocrit, acne, alterations in lipid values, and other effects related to androgens. The exact risks will vary from person to person and will depend on the particular formulation, the degree of exposure, and the individual's medical situation.