Where to Inject Testosterone: IM vs. SubQ Sites Explained

Testosterone injections go into either a large muscle (intramuscular, or IM) or the fat just under the skin (subcutaneous, or SubQ). IM shots usually go in the buttock or outer thigh, and SubQ shots usually go in the belly. AlphaMD providers prescribe both routes, and subcutaneous is the more frequent method for most men they see. Use the site your clinician teaches you.

This guide covers each site, what the product labels say, and how the choice gets made. If you are starting testosterone replacement therapy, use it alongside the hands-on training from your prescriber.

Why does the injection site matter?

The site decides which tissue the medicine goes into and which nerves and blood vessels sit nearby. The sciatic nerve is the nerve most often injured by IM injections (Jung Kim and Park, 2014). Clean technique matters too: washing your hands helps prevent infection (MedlinePlus).

Common injection sites for testosterone

Intramuscular (IM) injections

• Gluteal muscle (buttock): The DEPO-Testosterone (testosterone cypionate) label says IM injections "should be given deep in the gluteal muscle" (DEPO-Testosterone label). Within the buttock, a review of sciatic nerve injuries found the ventrogluteal site, on the side of the hip, has a better safety profile than the dorsogluteal site (the upper outer quadrant of the buttock) (Jung Kim and Park, 2014). A nursing literature review linked sciatic nerve injury to the dorsogluteal site and found wide agreement that the ventrogluteal site is preferable (Small, 2004). Have your clinician show you the landmarks.
• Vastus lateralis (outer thigh): This muscle runs along the outer side of the thigh, so it is easy to reach if you inject yourself. An anatomy study in young adults and cadavers found the middle of the vastus lateralis carries a low risk of hitting major blood vessels or nerves (Nakajima et al., 2019).
• Deltoid (shoulder): The deltoid has a small mass, so only small amounts of medicine can go there. The same study found that injecting about three finger-breadths below the top of the shoulder risks the axillary nerve and an artery that runs with it (Nakajima et al., 2019).

Testosterone cypionate "is not for intravenous use" (DEPO-Testosterone label).

Subcutaneous (SubQ) injections

• Abdomen: The belly is the usual SubQ site. Xyosted, a testosterone enanthate autoinjector, is labeled for the abdomen only. Its label says to use the left or right side of the belly, stay at least 2 inches from the navel, and avoid skin that is tender, bruised, red, scaly, hard, or scarred (Xyosted label).
• Thigh: MedlinePlus lists the outer side of the upper thighs as a general SubQ site (MedlinePlus). The Xyosted label says not to inject anywhere other than the abdomen, so the thigh is an option only when your prescriber chooses it for your product.

How do you choose the right injection site?

Start with what your clinician prescribed. Xyosted is labeled for SubQ injection in the abdomen (Xyosted label). The site also depends on your anatomy, your comfort, and what your prescriber teaches you.

Both routes can keep levels steady between weekly doses. In a phase II study of 39 men with hypogonadism, weekly SubQ testosterone enanthate restored normal levels "with low variation relative to 200-mg IM" (Kaminetsky et al., 2015).

On comfort, the best data are limited. In a retrospective study of 63 transgender men on weekly SubQ testosterone, all 22 who had switched from IM preferred SubQ, and none preferred IM; 9 of the 63 had minor, short-lived skin reactions (Spratt et al., 2017). That study was not randomized and did not include men with hypogonadism. For a longer comparison of the two routes, see intramuscular vs. subcutaneous testosterone injections.

Basic injection technique

Get hands-on training from your clinician before you inject on your own. For SubQ shots, MedlinePlus lists these steps (MedlinePlus):

• Wash your hands with soap and running water to help prevent infection.
• Clean the skin with an alcohol pad and let it dry.
• Use a new needle and syringe every time.
• Change the site with each injection, at least 1 inch from the last one.
• Afterward, hold clean gauze on the site for a few seconds to stop any bleeding.

For a fuller plan, see this guide to rotating injection sites to avoid scar tissue.

Some soreness at the site is expected. The DEPO-Testosterone label lists inflammation and pain at the injection site as a side effect (DEPO-Testosterone label). Contact your clinician if you see signs of infection, such as redness, swelling, red streaks, or a fever (MedlinePlus).

Special considerations for female patients

Testosterone in women has one evidence-based indication: hypoactive sexual desire disorder (HSDD, low sexual desire that causes distress), with recommendations written for postmenopausal women. The same consensus statement found insufficient data to support testosterone for any other symptom or condition (Global Consensus, 2019).

Polycystic ovary syndrome (PCOS) is not a reason to take testosterone. Most women with PCOS already make too much androgen (male sex hormone), which causes excess hair growth, acne, and male pattern hair loss (MedlinePlus Genetics).

AlphaMD offers testosterone therapy for women as cream, gel, and injectables. Dosing for women is outside the scope of this article.

Bottom line

For IM testosterone, the ventrogluteal area has a better safety profile than the upper outer buttock. The middle of the outer thigh is another low-risk IM site. For SubQ testosterone, the belly is the standard site, and Xyosted is labeled for the abdomen only. AlphaMD providers prescribe both intramuscular and subcutaneous testosterone, and subcutaneous is the more frequent route for most men they see. Use the site your prescriber teaches you, rotate sites, and call your clinician about signs of infection.