Testosterone shots are typically injected into one of three muscles: the outer thigh, the hip (ventrogluteal area), or the upper arm. Subcutaneous injections into the belly fat or thigh fat are also a safe, increasingly common option. The right site for you depends on whether your prescription calls for intramuscular or subcutaneous delivery, your comfort with reaching each area, and your body composition.
Intramuscular Injection Sites
Intramuscular (IM) injections deliver testosterone deep into muscle tissue, where it absorbs gradually into the bloodstream. Three sites are used most often.
Outer Thigh (Vastus Lateralis)
The outer thigh is the most popular site for self-injection because it’s easy to see and reach without help. The target is the middle outer portion of your thigh, roughly the area between one hand-width below your hip and one hand-width above your knee. You’re aiming for the thick band of muscle that runs along the outside of the leg, not the top or the inner thigh. Sit down, relax your leg, and insert the needle at a 90-degree angle. Most people find this site straightforward, though post-injection soreness in the thigh can be noticeable since you use this muscle constantly when walking.
Hip (Ventrogluteal)
The ventrogluteal site is located on the side of your hip, not the buttock cheek. Nurses and clinicians often prefer this site because the muscle here is thick (averaging about 40 mm in studies) and there are no major nerves or blood vessels nearby. To find it, use what’s called the V method: place the heel of your opposite hand on the bony prominence at the top of your outer thigh (the greater trochanter), point your index finger toward the front of your hip bone, and spread your middle finger back toward your waist. The injection goes into the V-shaped space between those two fingers. This site works well if someone else is giving you the shot. Self-injecting here is possible but takes some practice with positioning.
Upper Arm (Deltoid)
The deltoid muscle on the outer upper arm can be used for smaller-volume testosterone injections. The safe zone sits roughly two finger-widths below the bony point of your shoulder (the acromion). Going lower than that risks hitting the axillary nerve and a nearby artery. Because the deltoid is a smaller muscle, it’s best suited for injection volumes of 1 mL or less. This site is harder to self-inject since you need to use your non-dominant hand, but it’s convenient when a partner or healthcare provider is administering the shot.
Why the Upper Buttock Is Less Recommended
The dorsogluteal site, the classic “upper outer buttock” injection, was standard for decades. It has largely fallen out of favor because the sciatic nerve runs through this region, and the muscle layer is thinner here compared to the hip. Ultrasound studies in older adults found the dorsogluteal muscle averaged only about 26 mm thick, compared to 40 mm at the ventrogluteal site. The dorsogluteal area also tends to have a thicker layer of fat on top, which increases the chance the needle deposits medication into fat rather than muscle. If you were taught to inject into your buttock, switching to the ventrogluteal (hip) site is a safer alternative.
Subcutaneous Injection Sites
Subcutaneous injections go into the fat layer just beneath the skin rather than into muscle. Research published in The Journal of Clinical Endocrinology and Metabolism supports subcutaneous testosterone as a safe, practical option that produces stable hormone levels. Two areas work well.
The abdomen is the most common subcutaneous site. Inject about 3 to 5 cm (roughly 1.5 to 2 inches) to the side of your belly button, into the pinchable fat on either side. Avoid the area directly around the navel. The other option is the fatty tissue on the front or outer part of your thigh.
Subcutaneous shots use a shorter, thinner needle, which many people find less intimidating. A typical setup is a 25-gauge needle that’s 5/8 of an inch long. You pinch a fold of skin, insert the needle at about a 45-degree angle, inject slowly, and release. The smaller needle and shallower depth generally mean less soreness afterward compared to intramuscular shots.
Choosing the Right Needle
For intramuscular injections, a 22-gauge needle that’s 1 to 1.5 inches long is standard. The thicker gauge helps draw up the oily testosterone solution, and the length ensures the needle reaches muscle tissue past the skin and fat layers. If you carry more body fat at your injection site, a 1.5-inch needle is the safer choice to make sure you’re actually reaching the muscle.
For subcutaneous injections, a 25-gauge needle at 5/8 of an inch is typical. Some providers use a 23-gauge needle, which clinical experience suggests works well even for thicker, longer-acting testosterone formulations. You’ll often use a separate, larger needle (such as a 20-gauge) to draw testosterone out of the vial, then swap to the smaller needle for the actual injection. This keeps the injection needle sharp.
The Z-Track Technique
The Z-track method prevents testosterone from leaking back along the needle path into the tissue under your skin, which can cause irritation. Before inserting the needle, use your non-injecting hand to pull the skin and underlying tissue about an inch to one side. Hold it firmly. With your other hand, insert the needle at 90 degrees, inject the medication, pause for a few seconds, then withdraw the needle. Only then do you release the skin. The displaced tissue layers shift back into their natural position, creating a zigzag path that seals the medication inside the muscle. This technique is especially useful for oily testosterone solutions, which are more likely to track back through the needle hole.
Do You Need to Aspirate?
Aspiration means pulling back on the plunger after inserting the needle to check for blood, which would indicate you’ve hit a blood vessel. This step is no longer considered necessary for the recommended injection sites. The CDC notes that no large blood vessels are present at standard IM injection locations, and aspiration can actually increase pain. Most current clinical guidelines skip it entirely. If your provider specifically instructed you to aspirate, follow their guidance, but don’t worry if your instructions say to skip this step.
Why Site Rotation Matters
Injecting into the same spot repeatedly causes a buildup of fat, protein, and scar tissue under the skin, a condition called lipohypertrophy. These lumps aren’t just cosmetic. Scar tissue and fatty deposits change how predictably your body absorbs the medication, potentially leading to inconsistent hormone levels. The lumps also tend to feel numb, which makes them tempting to keep using since injections there hurt less. But continuing to inject into damaged tissue only worsens the problem and makes absorption even less reliable.
Create a simple rotation plan. If you inject weekly into your thigh, alternate between left and right legs. If you use multiple sites, you might rotate between your left thigh, right thigh, left abdomen, and right abdomen on a four-week cycle. Keep a written log or use a phone reminder so you don’t default to the same spot out of habit. Space each injection at least an inch away from any previous injection site, and avoid injecting into areas that are bruised, swollen, or tender.
Practical Tips for Self-Injection
Warm the testosterone vial in your hands for a minute or two before drawing it up. Testosterone is suspended in oil, and warming it slightly makes it flow more easily through the needle. Clean the injection site with an alcohol swab and let it air-dry completely before inserting the needle. Alcohol that hasn’t dried can sting when it’s pushed into the tissue.
Relax the muscle you’re injecting into. If you’re using your thigh, sit in a comfortable position with your leg relaxed rather than flexed. Tense muscles make the injection more painful and harder to push through. Insert the needle with a quick, dart-like motion rather than pressing in slowly, which actually causes more discomfort. After injecting, withdraw the needle at the same angle you inserted it and apply gentle pressure with a cotton ball or gauze. A small amount of bleeding is normal.
Some soreness at the injection site for a day or two is common, particularly with intramuscular shots. Applying a warm compress afterward can help. If you notice a growing lump, increasing redness that spreads outward, or warmth and pain that worsen over several days rather than improving, that could signal an infection rather than normal post-injection irritation.