Soon after the oral delivery of testosterone was deemed impractical due to rapid first pass metabolism, it was realized that pressed pellets of surgically implanted sterile testosterone could provide physiological androgen levels for extended periods of time to patients in need of such therapy. Implanted testosterone pellets were accepted very early as viable options for delivering testosterone, and various such commercial preparations have been introduced and prescribed over the years (although historically injectable esters and suspensions of testosterone have been the norm in this field of medicine).
Currently, Bartor Pharmacal produces the only commercially available brand of testosterone pellet in the U.S., sold as Testopel. Each pellet contains 75 mg of (free) testosterone. It is FDA-approved for use in adult males with conditions associated with a deficiency or absence of endogenous testosterone. This includes cases of primary hypogonadism caused by cryptorchidism, bilateral torsion, orchitis, vanishing testis syndrome, orchiectomy, Klinefelter’s syndrome, chemotherapy, or alcohol/heavy metal toxicity. It is also prescribed to treat hypogonadotrophic hypogonadism caused by tumors, injury, or radiation. FDA laws also allow certain private compounding pharmacies to manufacture generic testosterone implant pellet preparations. Testosterone implant pellets are not commonly made outside the U.S., but can be located in certain markets.
How is Testopel Supplied
Testosterone implant pellets are available in select human drug markets. Composition and dosage may vary by country or manufacturer, but generally contain approximately 98.5% pure testosterone (along with some inert binders) in a small cylindrical pressed pellet.
Structural Characteristics of Testopel
Sterile testosterone pellets for implantation contain (free) testosterone in a pressed pellet. The pellets are implanted subcutaneously with a minor surgical procedure, and slowly dissolve over time, releasing testosterone into the blood. Testosterone pellets are designed to provide testosterone for approximately 4-6 months following implantation.
Testopel 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. Exceeding therapeutic doses will increase the likelihood of estrogenic side effects. In such cases, an anti-estrogen such as clomiphene citrate or tamoxifen citrate (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.
Testopel Side Effects (Androgenic)
Testosterone is the primary male androgen, responsible for maintaining secondary male sexual characteristics. Exceeding normal therapeutic doses is 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. 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 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.
Testopel 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.
Testopel 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. Therapeutic doses of testosterone used to correct insufficient androgen production in otherwise healthy aging men are unlikely to increase atherogenic risk, and may actually reduce the risk of cardiovascular mortality.
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.
Testopel 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 the drug leaving the body. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.
Testopel Administration (General)
Sterile testosterone pellets are implanted subdermally in the lower abdominal wall. Prior to insertion, the skin is cleaned with alcohol and draped with a 2% xylocaine solution. A 2-cm incision is made through anaesthetized skin, and the pellets administered with the aid of a cannula. The incision site is covered with a sterile Band-Aid and a waterproof dressing for 1 week, and should not require stitching.
Testopel Administration (Men)
To treat androgen insufficiency, the prescribing guidelines for Testopel recommend implanting a row of 4-6 pellets (300-450 mg of testosterone) once every 4-6 months.
For physique- or performance-enhancing purposes, higher doses would be necessary to achieve supraphysiological levels of testosterone. This would be in the range of 12-18 pellets per application, which is not highly practical given the higher volume and surgical requirements for implantation.
Testopel Administration (Women)
Testopel is not FDA-approved for use in women. Testosterone implant pellets are not recommended for women for physique- or performance-enhancing purposes due to their strong androgenic nature, tendency to produce virilizing side effects, and very slow-acting characteristics.
Due to the relative impracticality of general private use, Testopel is not commonly traded on the black market.
Wlliam Llewellyn (2011) - Anabolics