Injection Sites
Testosterone Replacement Therapy (TRT) may be prescribed for men with confirmed testosterone deficiency after a medical assessment. When testosterone is administered by injection, the site of administration can influence comfort, absorption, and consistency of results.
Common injection sites include subcutaneous (under the skin), deltoid (shoulder), and ventrogluteal (hip) regions. Each has its own benefits, limitations, and safety considerations.
The choice of site should always be made in consultation with your AHPRA-registered doctor, who can ensure correct dosing, technique, and follow-up monitoring.
Subcutaneous (Subcut) Injections
Overview:
Subcutaneous injections deliver testosterone into the fatty tissue beneath the skin rather than into muscle.
Potential Advantages:
Often less painful compared to intramuscular injections.
Lower risk of muscle damage or post-injection soreness.
May provide a more stable release of testosterone over time.
Typically uses a smaller needle (27–30G, 5/8” or shorter), which may improve comfort.
Possible Limitations:
Limited volume capacity — usually suitable for smaller doses (up to around 0.2 mL).
Some individuals may notice small nodules or mild irritation under the skin at the injection site.
Deltoid (Shoulder) Injections
Overview:
The deltoid muscle is a convenient site for intramuscular (IM) injections and is commonly used for smaller volumes.
Potential Advantages:
Easily accessible for self-administration.
Allows for faster absorption due to good muscle vascularity.
Works well for low-volume doses (up to around 0.5 mL).
Possible Limitations:
Limited muscle depth can increase the chance of discomfort or poor placement.
The deltoid contains more nerve endings, which can lead to transient soreness.
Rotation is limited — frequent use of the same site can cause local irritation.
Ventrogluteal (Hip) Injections
Overview:
The ventrogluteal site located on the side of the hip.
Potential Advantages:
Low risk of hitting nerves or major blood vessels, unlike the dorsogluteal (buttock) site.
Can accommodate larger injection volumes (0.5 mL and above).
Typically well-tolerated when performed correctly.
Possible Limitations:
Can be difficult to reach for self-injection.
Requires correct anatomical identification to ensure proper placement and absorption.
Pharmacokinetic and Absorption Differences
Subcutaneous injections generally provide a slower, steadier release of testosterone, which may reduce peaks and troughs.
Intramuscular injections (deltoid or ventrogluteal) often have a faster uptake, which may lead to more variable hormone levels depending on dose and frequency.
Injection volume is an important consideration: smaller doses tend to be suitable for subcutaneous or deltoid sites, while larger volumes are better suited to ventrogluteal injections.
Hygiene, Safety, and Site Rotation
Proper injection technique and site care are critical to reduce the risk of infection or tissue damage. General principles include:
Wash hands thoroughly before preparation.
Use new, sterile needles and syringes for each injection.
Clean the injection site with an alcohol swab prior to injecting.
Dispose of sharps safely in an approved sharps container.
Rotate injection sites regularly to allow tissue recovery and prevent irritation, scarring, or uneven absorption.
Rotating between sites (e.g., alternating sides or regions) helps maintain tissue health and may improve comfort over the long term.
This information is provided for educational purposes only and does not replace professional medical advice, diagnosis, or treatment.
All injectable testosterone treatments should only be prescribed, initiated, and monitored by a qualified, AHPRA-registered doctor following appropriate testing and assessment.
Individual responses and site preferences vary. Always follow the clinical instructions and monitoring plan provided by your healthcare professional.