Perandren — testosterone phenylacetate

Testosterone phenylacetate is an injectable form of the primary male androgen testosterone. This compound uses a phenylacetate ester to extend the biological activity of testosterone, which, is very similar in structure to phenylpropionate. It is a short chain ester of testosterone, although was designed in this case to have a protracted effect in the body similar to testosterone cypionate or enanthate. As an injectable testosterone, testosterone phenylacetate is a powerful mass-building drug, capable of producing rapid gains in both muscle size and strength.

Brand name Perandren, Testosterone phenylacetate
Androgenic 100
Anabolic 100
Standard Standard
Chemical Names 4-androsten-3-one-17beta-ol
Estrogenic Activity moderate
Progestational Activity low

Perandren History

Testosterone phenylacetate was developed by Ciba during the 1960's, the same company to introduce Dianabol (methandrostenolone) to the world. This steroid was sold in the U.S. under the brand name of Perandren® phenylacetate, which incidentally had used the same Perandren name that Ciba had designated for its testosterone propionate years earlier (Perandren® propionate). At the time of its release, Perandren phenylacetate was intended to offer improvements over other esters of testosterone, most notably a longer window of therapeutic effect following each injection. Product information on the drug from 1967 reads, "[Perandren phenylacetate] Has a more prolonged action than other androgens and a markedly greater intensity of effect; in adequate dosage, a single injection per month suffices for many patients."

Early prescribing guidelines for testosterone phenylacetate called for a number of therapeutic uses. It was mainly applied to cases of male androgen insufficiency, and those issues normally surrounding low testosterone levels such as reduced sex drive and impotence in adults, and cryptorchidism (undescended testicles) in teenagers and young adults. But it also had such other uses as treating osteoporosis, menorrhagia (heavy menstrual bleeding), metrorrhagia (abnormal bleeding of the uterus), and breast cancer. It was also used to offset the catabolic effects of corticosteroids, to heal fractures, to promote wellness following surgery or convalescence, and as a general tissue-repairing anabolic when needed.

The life of Perandren phenylacetate on the U.S. prescription drug market was ultimately a short one. By the late 1960's, other "new" esters of testosterone were also widely available, namely testosterone cypionate and enanthate, and Ciba's slow-acting creation was quickly losing market share to these agents. These esters of testosterone offered a similar period of therapeutic benefit to Perandren phenylacetate, but with considerably more patient comfort (they did not need to be mixed with anesthetic for injections to be semi-tolerable like Perandren phenylacetate). As a result of this shift in consumer interest, Ciba withdrew this product from market. By 1970, Perandren phenylacetate was no longer available.

How is Perandren Supplied

Testosterone phenylacetate is no longer commercially available. When produced, it contained 50 mg/ml of steroid in a water-based solution.

Structural Characteristics of Perandren

Testosterone phenylacetate is a modified form of testosterone, where a carboxylic acid ester (acetic acid phenyl ester) has been attached to the 17-beta hydroxyl group. Esterified forms of testosterone are less polar than free testosterone, and are absorbed more slowly from the area of injection. Once in the bloodstream, the ester is removed to yield free (active) testosterone. Esterified forms of testosterone are designed to prolong the window of therapeutic effect following administration, allowing for a less frequent injection schedule compared to injections of free (unesterified) steroid.

Perandren Side Effects (Estrogenic)

Testosterone is readily aromatized in the body to estradiol (estrogen). The aromatase (estrogen synthetase) enzyme is responsible for this metabolism of testosterone. Elevated estrogen levels can cause side effects such as increased water retention, body fat gain, and gynecomastia. Testosterone is considered a moderately estrogenic steroid. An anti-estrogen such as clomiphene citrate or tamoxifen citrate may be necessary to prevent estrogenic side effects. One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which more efficiently controls estrogen by preventing its synthesis. Aromatase Inhibitors can be quite expensive in comparison to anti-estrogens, however, and may also have negative effects on blood lipids.

Estrogenic side effects will occur in a dose-dependant manner, with higher doses (above normal therapeutic levels) of testosterone more likely to require the concurrent use of an anti-estrogen or aromatase inhibitor. Since water retention and loss of muscle definition are common with higher doses of testosterone, this drug is usually considered a poor choice for dieting or cutting phases of training. Its moderate estrogenicity makes it more ideal for bulking phases, where the added water retention will support raw strength and muscle size, and help foster a stronger anabolic environment.

Perandren Side Effects (Androgenic)

Testosterone is the primary male androgen, responsible for maintaining secondary male sexual characteristics. Elevated levels of testosterone are likely to produce androgenic side effects including oily skin, acne, and body/facial hair growth. Men with a genetic predisposition for hair loss (androgenetic alopecia) may notice accelerated male pattern balding.Those concerned about hair loss may find a more comfortable option in nandrolone decanoate, which is a comparably Jess androgenic steroid. Women are warned of the potential virilizing effects of anabolic/androgenic steroids, especially with a strong androgen such as testosterone. These may include deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement.

In androgen-responsive target tissues such as the skin, scalp, and prostate, the high relative androgenicity of testosterone is dependant on its reduction to dihydrotestosterone (DHT). The 5-alpha reductase enzyme is responsible for this metabolism of testosterone. The concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride will interfere with site-specific potentiation of testosterone action, lowering the tendency of testosterone drugs to produce androgenic side effects. It is important to remember that anabolic and androgenic effects are both mediated via the cytosolic androgen receptor. Complete separation of testosterone's anabolic and androgenic properties is not possible, even with total 5-alpha reductase inhibition.

Perandren Side Effects (Hepatotoxicity)

Testosterone does not have hepatotoxic effects; liver toxicity is unlikely. One study examined the potential for hepatotoxicity with high doses of testosterone by administering 400 mg of the hormone per day (2,800 mg per week) to a group of male subjects. The steroid was taken orally so that higher peak concentrations would be reached in hepatic tissues compared to intramuscular injections. The hormone was given daily for 20 days, and produced no significant changes in liver enzyme values including serum albumin, bilirubin, alanine-amino-transferase, and alkaline phosphatases.

Perandren Side Effects (Cardiovascular)

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance tp hepatic metabolism. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.

Testosterone tends to have a much less dramatic impact on cardiovascular risk factors than synthetic steroids. This is due in part to its openness to metabolism by the liver, which allows it to have less effect on the hepatic management of cholesterol. The aromatization of testosterone to estradiol also helps to mitigate the negative effects of androgens on serum lipids. In one study, 280 mg per week of testosterone ester (enanthate) had a slight but not statistically significant effect on HDL cholesterol after 12 weeks, but when taken with an, aromatase inhibitor a strong (25%) decrease was seen. Studies using 300 mg of testosterone ester (enanthate) per week for 20 weeks without an aromatase inhibitor demonstrated only a 13% decrease in HDL cholesterol, while at 600 mg the reduction reached 21%. The negative impact of aromatase inhibition should be taken into consideration before such drug is added to testosterone therapy.

Due to the positive influence of estrogen on serum lipids, tamoxifen citrate or clomiphene citrate are preferred to aromatase inhibitors for those concerned with cardiovascular health, as they offer a partial estrogenic effect in the liver.This allows them to potentially improve lipid profiles and offset some of the negative effects of androgens. With doses of 600 mg or less of testosterone per week, the impact on lipid profile tends to be noticeable but not dramatic, making an anti-estrogen (for cardioprotective purposes) perhaps unnecessary. Doses of 600 mg or less per week have also failed to produce statistically significant changes in LDL/VLDL cholesterol, triglycerides, ^polipoprotein B/C-lll, C-reactive protein, and insulin sensitivity, all indicating a relatively weak impact on cardiovascular risk factors. When used in moderate doses, injectable testosterone esters are usually considered to be the safest of all anabolic/androgenic steroids.

To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.

Perandren Side Effects (Testosterone Suppression)

All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Testosterone is the primary male androgen, and offers strong negative feedback on endogenous testosterone production. Testosterone-based drugs will, likewise, have a strong effect on the hypothalamic regulation of natural steroid hormones. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.

Perandren Administration (General)

The design of testosterone phenylacetate (as Perandren phenylacetate) was slightly different than that of most testosterone esters, which are usually made as oily solutions. Phenylacetate instead contained a microcrystalline aqueous suspension. The crystals would form a repository in the muscle following injection, where they would slowly dissolve over time. Product information on Perandren phenylacetate stated that injections could result in local irritation, pain, and redness. To help offset the discomfort associated with injection, each vial contained 1% procaine by weight, which acted as a local anesthetic. Although this was an effective method of delivering testosterone over time, patient comfort was likely not ideal with this formulation.

Perandren Administration (Men)

To treat androgen insufficiency, early prescribing guidelines recommended a dosage of 50 mg to 200 mg given every 3 to 5 weeks. An adequate dosage among male athletes would be in the range of 200 mg to 400 mg per week. Although active for longer periods of time, weekly injections would be preferred due to the low dosage and tendency for pain at the site of injection (large injection volumes would not be advised). The total weekly dosage may need to be further subdivided into two or more separate injections. A 200-400 mg per week dosage level would be sufficient for most users to notice exceptional gains in muscle size and strength.

Perandren Administration (Women)

Product information for Perandren phenylacetate recommended no more than 150 mg per month for women, so as to avoid virilizing side effects. In modern clinical medicine, testosterone compounds are rarely used with women. Testosterone phenylacetate is not recommended for WQmen for physique- or performanceenhancing purposes due to its strong androgenic nature and tendency to produce virilizing side effects.

Perandren Availability

Testosterone phenylacetate is no longer commercially available. The raw material is available from certain manufacturers, and may turn up in black market (underground) preparations.


Wlliam Llewellyn (2017) - Anabolics

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