Testosterone Suspension

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Androgenic 100
Anabolic 100
Standard Testosterone (Standard)
Chemical Names 4-androsten-3-one-17beta-ol, 17beta-hydroxy-androst-4-en-3-one
Estrogenic Activity moderate
Progestational Activity low


Testosterone suspension is an injectable preparation containing testosterone (no ester), usually in a water base. Among bodybuilders, “suspension” is known to be an extremely potent mass agent. It is often said to be the most powerful injectable steroid available, producing very rapid gains in muscle mass and strength. This is largely due to the very fast action of the drug. When using a slow-acting oil-based steroid like Sustanon® 250, it can take weeks before a peak testosterone level is reached. With suspension, it is just a matter of hours. This will usually result in the athlete starting to notice size and strength gains by the end of the first week. By the time the athlete is 30 days into a cycle of suspension, the length it will usually take for Sustanon® 250 to really begin working consistently, the mass gains are already (generally) very extreme.


Testosterone suspension is one of the oldest anabolic/androgenic steroids, dating all the way back to the 1930’s. Used generically to describe any injectable form of free testosterone, testosterone suspension predates the development of slow-acting (depot) injections of esterified testosterone by several years. Even after the development of esterified derivates, testosterone suspension remained on the U.S. and other select drug markets. For example, testosterone propionate and testosterone enanthate were both commercially available by the 1950’s, yet testosterone suspension remained a regularly produced item in the U.S. for decades more. Previous American trade names for the drug have include Sterotate (Ulmer), Andronaq (Central), Aquaspension Testosterone (Pitman-Moore), Injectable Aqueous Testosterone (Arlington-Funk), Virosterone (Endo), and Testosterone Aqueous (National Drug). A full accounting of the former generic manufacturers and brand names for this drug would be too numerous to list.

Testosterone suspension shares a clinical application history similar to that of other testosterone products. Early prescribing guidelines called for its use to ameliorate a loss of sex drive, impotence, and general loss of vitality in aging males with declining hormone levels. Testosterone was/is also used to treat pubertal adolescents with undescended testicles. With women, the drug was commonly prescribed for the treatment of excessive or painful lactation following childbirth, as well as inoperable mammary cancer. By the 1990’s, however, the FDA had refined the approved uses for testosterone suspension slightly, which began to focus more tightly on the treatment of male androgen insufficiency. The drug may, however, still be used as a secondary therapy in inoperable breast cancer, although its high tendency to produce virilization makes it an uncommon choice.

Although the number of products containing testosterone suspension steadily dwindled over the years, the drug enjoyed uninterrupted availability on the U.S. prescription drug market all the way up to 1998. That year, the FDA had taken action against Steris Laboratories (a subsidiary of Henry Schein), which at the time was the principal U.S. supplier for testosterone products (manufacturing them for their label and several other brands). The firm was also the last remaining producer of testosterone suspension. The dispute arose over Steris’ inventory reports for their Class III drugs. The FDA forced the company to suspend production of all C-III pharmaceuticals until certain “discrepancies” could be addressed. Years later, Steris was able to resume producing testosterone drugs again, but by this time had made the decision not to resume making testosterone suspension. Currently, testosterone suspension is still available in the U.S., but only through private compounding pharmacies, which may produce the drug on special order from a licensed doctor.

How Supplied:

Testosterone suspension is available in select human and veterinary drug markets. Composition and dosage may vary by country and manufacturer, but usually contain 50 mg/ml or 100 mg/ml of steroid mixed in a water-based solution. Testosterone has low water solubility, so the steroid will noticeably separate from a water-based solution when a vial or ampule is left to sit. A quick shake will temporarily place the drug back into suspension, so that the withdrawn dosage should always be consistent.

testosterone structure molecule

Structural Characteristics:

Testosterone suspension contains (free) testosterone in a water-based suspension, although oils are sometime also used as carriers. Without esterification, testosterone has a short half-life in the body. Testosterone suspension may require a minimum of 2-3 injections per week to maintain consistent hormone elevations. When calculating dose, especially when moving from one testosterone preparation to another, it is also important to remember that testosterone suspension contains more active testosterone per milligram than its esterified derivatives. For example, when the weight of the ester is taken into account, 100 mg of testosterone enanthate actually only provides 72 mg of raw testosterone.

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.

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.426

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.427Studies 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%.428 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, apolipoprotein B/C-III, C-reactive protein, and insulin sensitivity, all indicating a relatively weak impact on cardiovascular risk factors.429 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.

The above side effects are not inclusive. For more detailed discussion of potential side effects, see the Steroid Side Effects section of this book.

Administration (General):

Testosterone suspension contains undissolved testosterone particles, which form a short-acting repository in the muscle following injection. Depending on the size of the particles and other agents present, injections of testosterone suspension may result in local irritation, pain, and redness. Veterinary testosterone suspensions may use large particles that require a needle as large as 21 gauge for injection, for example, and can be very uncomfortable to use. Modern testosterone suspension preparations made for human use often contain microcrystalline steroid particles. These crystals are highly refined, and are too small to see with the naked eye. This design provides significantly more patient comfort than less refined products, and is generally well tolerated.

Administration (Men):

To treat androgen insufficiency, the prescribing guidelines for testosterone suspension recommend a dose of 25-50 mg, which is given 2-3 times per week. When used for muscle-building purposes, testosterone suspension is often administered at a dose of 100-200 mg per injection, which is given every 2nd or 3rd day. Athletes looking to achieve an extremely rapid bulk gain will inject as much as 100 mg daily. In most cases this higher dose can be amazing, the user seeming to just inflate with bloated muscle mass in a very short period of time. Back when they were being manufactured, the U.S. 30 mL vials (100 mg/mL) were always the most sought after for this procedure, as each would run the cycle for about a month. Although this drug does require a frequent injection schedule, a well-refined suspension should pass through a needle as fine as 27 gauge (insulin). This allows the user more available injection sites, hitting the smaller muscle groups such as the deltoid, triceps, and calves.

Those looking for only a potent mass agent are often extremely happy with the results provided by testosterone suspension; this product certainly has a strong reputation for performing. But those athletes who want not just quantity but quality are likely to be disappointed, as the muscle mass gain is not going to be a hard, dense one. In fact, the user will often have to contend with excessive fat and water-weight gains when building their physique with this drug, and will often seek the benefit of cutting agents soon afterwards to clean up the look of muscularity. Alternately, one could make use of a smaller dosage of testosterone suspension, which would allow for less estrogen buildup. In such a scenario, one could stack it with any of a variety of other less or non-aromatizable steroids, depending on the desired goals.

Administration (Women):

Testosterone suspension is rarely used with women in clinical medicine. When applied, it is most often used as a secondary treatment for inoperable breast cancer. Doses given for this application may reach 100 mg three times per week, a level well into the threshold likely to cause strong virilizing side effects. Testosterone suspension is not recommended for women for physique- or performance-enhancing purposes due to its strong androgenic nature and tendency to produce virilizing side effects.


Pharmaceutical preparations containing testosterone in an aqueous suspension remain scarce. The bulk of the supply presently comes from underground and export steroid manufacturers. In reviewing some of the remaining products and changes in the global pharmaceutical market, we have made the following observations.

Testosterone suspension has been unavailable in the United States for many years now. No old products should still be in circulation. Because the FDA never officially withdrew this drug from, it can be specially ordered through a small number of compounding pharmacies. Anything else bearing a U.S. manufacturer name is counterfeit.

Testosterone suspension is still produced in India under the Aquaviron brand name, now by Piramal HC. It comes in the strength of 25 mg/mL, and is packaged in 1 mL ampules.



426. Enzyme induction by oral testosterone. Johnsen SG, Kampmann JP, Bennet EP, Jorgensen F. 1976 Clin Pharmacol Ther 20:233-237.
427. High-density lipoprotein cholesterol is not decreased if an aromatizable androgen is administered. Friedl K, Hannan C et al. Metabolism 39(1) (1990):69-74.
428. Testosterone dose-response relationships in healthy young men. Bhasin S, Woodhouse L et al. Am J Physiol Endocrinol Metab 281 (2001):E1172-81.
429. The effects of varying doses of T on insulin sensitivity, plasma lipids, apolipoproteins, and C-reactive protein in healthy young men. Atam Singh, Stanley Hsia, et al. J Clin Endocrinol Metab 87 (2002):136-43.


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By | 2017-04-07T01:11:54+00:00 April 11th, 2015|Categories: Steroid Profiles|0 Comments

About the Author:

William Llewellyn is a researcher in the field of human performance enhancement. He is also author of the bestselling ANABOLICS book series, most recently the ANABOLICS 10th Edition. William is an active supporter of the harm reduction community, and currently serves as honorary lecturer at the Centre for Public Health at Liverpool John Moores University.

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