Proper site selection can also minimize discomfort and reduce the risk of complications such as infection or tissue damage. Injectable testosterone is one of the most commonly prescribed forms of testosterone replacement therapy (TRT) . While there are various way...Testosterone replacement therapy is a common treatment for m...Read More However, improper technique or injecting into the wrong location can potentially cause pain or discomfort that may temporarily limit movement. What are the alternatives if I cannot inject into the deltoid? There is no concrete evidence that time of day affects the absorption rate of testosterone from the deltoid. This guide is designed to educate patients about the different injection sites, the pros and cons of each, and how to choose the best option for your needs. At AlphaMD, we understand that beginning testosterone therapy can bring up many questions, one of the most common being, "Where should I inject testosterone?" For Testosterone, injections are much better than creams and gels. At AlphaMD.org, we understand that personalized treatment is key in testosterone replacement therapy (TRT). If done correctly using proper technique, injecting testosterone in the deltoid should not affect shoulder function or mobility. Can injecting testosterone in the deltoid affect my shoulder function or mobility? Alternatives if you cannot inject into the deltoid include the gluteus maximus (buttocks) and the vastus lateralis (thigh) muscles. Figure 1 and Table 1 present the structures underlying the deltoid muscle. This study analyzes the procedures of IMI administration in the deltoid in relation to the arterial network underlying the muscle. Limitations included the unavailability of free access to complete text in many articles resulting in exclusion. All the authors strictly adhered to a well-developed registered review protocol throughout the study and followed the risk of bias in systematic reviews (ROBIS) guidance tool. This study analyzes the procedures of administering IMIs in the deltoid related to the neurovascular network underlying the muscle and proposes a preferred site with the least chance of injury. Proper technique is non-negotiable when injecting testosterone in the deltoid. Testosterone replacement therapy (TRT) has become increasingly common for men experiencing low testosterone levels. Free access to complete text was unavailable for several articles; thus, a review of such articles could not be performed because abstracts were excluded from our study. Further cadaveric and ultrasonographic studies are needed to study the neurovascular profile in relation to safer areas for IMI in the deltoid muscle. This site is far below the surgical neck of the humerus (7 cm), the AXN (7 cm), the subdeltoid bursa (5 cm), and the PCHA (7.6 +/-1.0 cm); therefore, the chance of injury to blood vessels and nerves is the least. Based on the neurovascular network lying underneath the deltoid muscle and in relation to the upper end of the humerus, the proximal humerus is related to a network of arteries arising from the second part of the axillary artery. General pharmacokinetic comparisons appear in the TRT pharmacology review (PMC). Label presentations and administration details for injectable formulations are summarized on Mayo Clinic’s drug page and in the Drugs.com monograph. You can see the labeled ranges in the Drugs.com dosage monograph, while monitoring/titration principles are detailed in the Endocrine Society guideline. Drug references explicitly note that dosing should be individualized to response and adverse effects, not set-and-forget (see the Drugs.com dosage monograph). Safety monitoring typically includes hematocrit (screen for erythrocytosis), PSA and prostate assessment as age-appropriate, blood pressure, and a lipid profile. Mainstream guidance emphasizes titrating to symptom relief and aligning lab timing with the formulation (e.g., the Endocrine Society’s detailed recommendations in J Clin Endocrinol Metab, 2018 and this concise AUA educational update). After a dose change, follow-up commonly occurs at 3–6 months, then periodically once stable.
