Testosterone Blend

Omnadren® 250 (Testosterone blend) in its original formulation, was an oil-based injectable testosterone blend that contained four different testosterone esters: testosterone propionate (30 mg); testosterone phenylpropionate (60 mg); testosterone isocaproate (60 mg); and testosterone caproate (100 mg). Being a four-component testosterone blend, this preparation was most commonly compared to Sustanon® 250. While it did contain testosterone propionate, phenylpropionate, and isocaproate in the same strengths as Sustanon®, the last ester is different. It was a slightly shorter-acting drug, making Omnadren® more analogous to Testoviron® (the caproate ester is one carbon shorter than enanthate) than Sustanon® 250. Please note that there were even older versions of Omnadren® listing isohexanoate and hexanoate as the final two ingredients, which are simply different words for isocaproate and caproate.


Omnadren® 250 was developed in Poland by Polfa during the years of Soviet control. Its formulation (original) is very similar to that of Sustanon® 250, barring the substitution of one of the component esters. This was likely done to avoid patent issues with the international pharmaceutical giant Organon, which exclusively controlled the global supply of Sustanon® 250. In clinical medicine, Omnadren® 250 was used most commonly to treat adult men suffering from low androgen levels, usually noticing symptoms of impotence or hormonal disturbance of spermatogenesis. This drug was also used on occasion to treat adolescents with delayed puberty, and women with advanced breast or endometrial cancer.

The manufacture of Omnadren® 250 under the Polfa label was discontinued in 1994. That year, the newly privatized Polfa firm was renamed Jelfa, mainly to distinguish itself from other firms that use a Polfa prefix as part of their names. Jelfa continued to produce Omnadren® 250 for the domestic market, which remained available without interruption in the same familiar 5-pack of ampules (albeit with a new company label and logo) for years after. Today, Jelfa continues to market Omnadren® 250 in Poland, as well as in many neighboring markets including Russia, Ukraine, Kazakhstan, Uzbekistan, Kurdistan, Kyrgyzstan, Armenia, Moldavia, Latvia, Lithuania, Azerbaijan, Georgia, and Belarus, however, the formulation has recently changed. All Omnadren 250 sold today carries the same exact formulation as Sustanon 250. This profile refers to the original formulation only, which is now unavailable worldwide.

How Supplied

Omnadren® 250 (original formulation) in no longer available. When manufactured, it was supplied in 1 mL glass ampules containing an oily solution; sold in boxes of 5 ampules.

Structural Characteristics

Omnadren® 250 contains a mixture of four testosterone compounds, which were modified with the addition of carboxylic acid esters (propionic, propionic phenyl ester, isocaloric, and caproic acids) at 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. Omnadren® 250 is designed to provide a rapid peak in testosterone levels (24-48 hours after injection) and maintain physiological concentrations for approximately 14 days.

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-dependent 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.

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 less 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.

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.

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 to 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.1Studies 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 a 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, apolipoprotein B/C-III, 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.

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.

Administration (General)

Testosterone propionate is often regarded as a painful injection. This is due to the very short carbon chain of the propionic acid ester, which can be irritating to tissues at the site of injection. Many sensitive individuals choose to stay away from this steroid completely, their bodies reacting with a pronounced soreness and low-grade fever that may last for a few days after each injection.

Administration (Men)

Depending on the application, the prescribing guidelines for Omnadren® 250 calls for a dosage of 250 mg (1 ampule) to be injected every 3 to 4 weeks. Although active in the body for a longer time, Omnadren® 250 is usually administered on a weekly basis for muscle-building purposes. This schedule will allow for the higher doses most commonly applied by athletes, and more stable elevations in hormone level. The usual dosage among male athletes is in the range of 250-750 mg per injection, taken in cycles 6 to 12 weeks in length. This level is sufficient for most users to notice exceptional gains in muscle size and strength. Some bodybuilders have been known to use excessively high dosages of this drug (1,000 mg per week or more), although this practice is generally not advised due to the higher incidence of side effects. Testosterone is ultimately very versatile and can be combined with many other anabolic/androgenic steroids to tailor the desired effect.

Administration (Women)

Omnadren® 250 is rarely used with women in clinical medicine. When applied, it is most often used to treat inoperable breast or endometrial cancer. Omnadren® 250 is not recommended for women for physique- or performance-enhancing purposes due to its strong androgenic nature, tendency to produce virilizing side effects, and slow-acting characteristics (making blood levels difficult to control).


The original Omnadren 250 formulation is no longer available. Jelfa continues to use the trade name to market a steroid product, but it is now equivalent in makeup to Sustanon 250. See the Sustanon 250 profile for more information.


  1. High-density lipoprotein cholesterol is not decreased if an aromatizable androgen is administered. Karl Friedl, Charles Hannan et al. Metabolism 39(1) 1990:69-74.