TRT injection sites: what the evidence says about technique

What did @kmartfit actually say?

The creator, who says they've been on testosterone replacement therapy for three years, demonstrates how they personally inject testosterone. Their method: divide the glute into four quadrants using one vertical and one horizontal line, target the upper outer quadrant, pinch the muscle, and inject. That's the gist. No dosing claims, no brand recommendations, just a site-selection tutorial from someone with apparent personal experience.

It's a short video, so there isn't much to unpack. But short doesn't mean consequence-free. Injection technique in TRT matters more than most people realize, and the guidance here is partially right, partially incomplete, and missing some details that could actually protect someone from nerve damage or infection.

Does the science back this up?

Mostly, yes. The upper outer quadrant of the gluteus maximus, often called the ventrogluteal or dorsogluteal site depending on exact placement, is one of the most commonly recommended intramuscular injection sites in clinical practice. The American Nurses Association and multiple injection technique reviews support its use precisely because it keeps the needle away from the sciatic nerve and major blood vessels.

A 2015 systematic review by Cocoman and Murray in the Journal of Clinical Nursing confirmed that dorsogluteal and ventrogluteal sites both have strong safety profiles when the upper outer quadrant is correctly identified. The sciatic nerve runs through the lower and medial portions of the glute, so targeting the upper outer quadrant is the right instinct. @kmartfit isn't wrong here. This is textbook-adjacent guidance that aligns with what nurses are taught in clinical training.

What did they get wrong (or right)?

Let's give credit where it's due. The quadrant-division method is a legitimate and widely taught anatomical landmark technique. Pinching the muscle before injection is debated in clinical literature. For intramuscular injections, the standard recommendation from the CDC and most nursing protocols is to use the Z-track method, not pinching. Pinching is more appropriate for subcutaneous injections. This is a real distinction that matters.

A 2019 review by Hunter in Nursing Standard specifically notes that pinching tissue before an IM injection can inadvertently cause the needle to enter subcutaneous fat rather than muscle, reducing absorption efficiency and potentially causing local irritation or nodule formation. For testosterone cypionate or enanthate, which are oil-based and require IM delivery for proper pharmacokinetics, that's not a trivial concern.

What's also missing: needle length selection, aspiration debate, angle of entry, and any mention of sterile technique. None of those are niche concerns. They're foundational.

What should you actually know?

If you're administering TRT injections at home, the injection site is just one piece of the picture. Here's what the research actually supports:

• The upper outer glute quadrant is a legitimate and safe IM injection site, but the ventrogluteal site (anterior gluteal region near the iliac crest) has growing clinical support as potentially safer, per a 2016 analysis in Applied Nursing Research by Wynaden et al.
• Pinching before an IM injection is not standard protocol. The Z-track method, where you pull the skin laterally before inserting the needle and release after withdrawing, is preferred for reducing leakage and irritation with oil-based solutions like testosterone esters.
• Needle length matters. Body composition affects how deep you need to go to reach muscle. A 1-to-1.5 inch needle is typical for most adults, but that's a conversation to have with your prescribing clinician, not a TikTok video.
• Sterile technique is non-negotiable. Swabbing the injection site with 70% isopropyl alcohol and allowing it to dry fully before injecting is required, not optional.
• Rotating injection sites reduces the risk of lipohypertrophy, a buildup of fibrous tissue from repeated injections in the same spot.

TRT self-injection is a legitimate medical practice when prescribed and supervised properly. But tutorials like this one, however well-intentioned, shouldn't be your primary clinical education.

Bottom line: should you follow this advice?

The upper outer quadrant site selection is sound. The pinching technique is not standard for intramuscular injections and could actually compromise absorption. The video is fine as a rough orientation but is missing too much context to be a reliable standalone guide. If you're on a regulated TRT program, your clinical team should be walking you through injection technique directly, ideally with written instructions and a chance to ask questions. A 30-second TikTok, even a well-meaning one, isn't a substitute for that conversation.