Testosterone has commonly been administered as an intramuscular (IM) injection since the 1930’s. While many testosterone products have been introduced into the market place to make the administration of testosterone more user friendly, such as testosterone gels, trans nasal testosterone, transdermal testosterone preparations, oral testosterone tablets, testosterone pellets and long-acting testosterone esters, intramuscular testosterone injections have been the most potent, proven, reliable and most cost effective way to to replace testosterone.
Another route of testosterone injection into the subcutaneous (Subq) fat has proven to achieve steady state and therapeutic stable serum testosterone levels in male patients similar to intramuscular testosterone injections. Subcutaneous testosterone injections offer the following benefits:
Ease of administration and less discomfort
Minimal testosterone peak and trough fluctuations
Less chance of venipuncture
Additional information about SubQ Testosterone Injections
Testosterone cypionate and Testosterone enanthate are thick viscous solutions. The needle used to draw up and inject intramuscular testosterone is often a 22-23 gauge needle.
When injecting testosterone into the subcutaneous fat under the skin, the same same needle is used to draw up testosterone but a different much finer, thinner and shorter needle is used for the injection .
A 18-to-22-gauge needle is used to draw the testosterone solution into a 1cc syringe to the desired amount. The needle is removed and replaced with a fine 25- or 27-gauge 5/8-inch needle. Commonly used sites for Subq injection of testosterone include the abdominal fat or the thigh.
Sterile technique and all injection precautions utilized with IM injections are identical to the subcutaneous testosterone injection technique. Always clean, with an alcohol prep pad, the top the testosterone vial and the skin prior to puncture and injection of testosterone.
Testosterone is dissolved in an oil commonly grapeseed or cottonseed oil. Grapeseed oil often has a lower viscosity and is much easier to inject through a fine injection needle compared to cottonseed oil. For this reason, testosterone in grapeseed oil is the optimal solution to inject testosterone via the subcutaneous route.
Subcutaneous testosterone can be injected biweekly or weekly similar to the IM route of testosterone injection. While some clinics may have advise patients to inject a low dose of testosterone daily, the majority of studies investigated the efficacy of subcutaneous testosterone injection weekly or biweekly.