Keywords: Subcutaneous injection of Testosterone, Intramuscular Injection of Testosterone,
Xyosted ®, Testosterone Enanthate, Painless Testosterone Injection.
Since the 1950’s testosterone has been primarily administered by intramuscular injection for men with testosterone deficiency (< 300ng/dL) and symptoms of Low-T. Testosterone replacement formulations have evolved since the 1950's and many androgen formulations are available to choose from to replace testosterone : transdermal patches, topical gels, nasal testosterone, sub-dermal testosterone pellets, oral testosterone.
Yet, there has been increasing evidence and support that testosterone can be given by subcutaneous injection, rather than by intramuscular injection. Benefits of subcutaneously injecting testosterone include less discomfort and pain, smaller needle size, and possibly lesser dosages of testosterone needed to sustain steady state levels of serum testosterone.
In a pilot study by Al-Futaisi MD et. al., Subcutaneous Administration of Testosterone,
22 male patients with primary and secondary hypogonadism were recruited from a Canadian endocrine clinic and asked to inject 25-50mg of testosterone enanthate using a 0.5 ml insulin syringe. Patients reportedly warmed the testosterone ester by placing the bottle underneath the axilla (arm pit) for 5 min prior, reducing the compounds viscosity and easing the injection application. Patients’ serum testosterone levels were then measured and monitored over a 1-year period from January 2002 to December 2002. Results of the study revealed that serum testosterone peaks and troughs were 100% within the normal range of testosterone. Furthermore, subcutaneous injection of testosterone weekly was able to maintain testosterone levels within the normal reference range.
An additional study from Spratt et. al, Subcutaneous Injection of Testosterone Is an Effective and Preferred Alternative to Intramuscular Injection…, published in the Journal of Clinical Endocrinology and Metabolism, 63 patients were provided subcutaneous testosterone injection at an initial dose of 50mg weekly. Results, in short, revealed that the subcutaneous route of injecting testosterone was able to normalize testosterone levels, reduce injection site pain and is well tolerated and preferred by some patients.
A new subcutaneous auto injector pre-filled with Testosterone Enanthate (with dosages of 50mg, 75mg and 100mg) called Xyosted ® was recently approved by the FDA in 2018 for testosterone deficiency. This medication type is new step in the direction of subcutaneous testosterone injections becoming more mainstream and as alternative to the commonly advocated intra muscular route.
According to studies, subcutaneous use of testosterone enanthate (Xysoted ®) resulted in a steady level of testosterone after 6 weeks of use, with very narrow testosterone fluctuations. According to the manufacturer’s website, patients are started on 75mg of Testosterone Enanthate weekly, and 50% patients of do not need dose adjustments. The most common side effect of Xyosted® includes an elevation in blood pressure most commonly experienced by users during the first 12 weeks of treatment.