Pinning testosterone means injecting it into muscle or fat tissue using a syringe and needle. Whether you’re doing your first injection or refining your technique, the process follows the same core steps: gather sterile supplies, prep the vial and your skin, inject slowly into a relaxed muscle or fat pad, and rotate your sites each time. Here’s how to do it safely and with minimal pain.
Intramuscular vs. Subcutaneous: Pick Your Method
Testosterone can be injected into muscle (intramuscular, or IM) or into the fat layer just beneath the skin (subcutaneous, or SubQ). Both deliver the same hormone, and at steady state the bioavailability is similar regardless of route. The practical differences come down to needle size, injection depth, and how your levels behave between shots.
SubQ injections produce more stable absorption because blood flow in fat tissue is steadier than in muscle, where physical activity can speed up drainage. After a SubQ shot, testosterone peaks at around 8 days compared to about 3.3 days with IM. That slower rise means fewer spikes. In one study, a 200 mg IM dose pushed testosterone above the normal range during the first week, while a 100 mg SubQ dose kept levels within range and delivered a similar total exposure over the same period. Duration of action is nearly identical: about 104 days for SubQ and 101 for IM.
SubQ uses a shorter, thinner needle and is generally less intimidating for beginners. IM delivers into a larger tissue space, which some people prefer for higher-volume injections. Your prescriber may recommend one over the other, but both are well-supported options.
Supplies You Need
Testosterone is suspended in a thick oil (usually sesame or cottonseed), so you’ll often use two different needles: a larger one to draw the oil out of the vial and a smaller one to actually inject. Drawing through a thin needle takes forever with viscous oil and dulls the tip before it touches your skin.
- Syringe: A 1 mL or 3 mL Luer-Lock syringe works for most doses.
- Drawing needle: An 18- or 20-gauge needle pulls oil quickly from the vial.
- Injecting needle (IM): A 23-gauge, 1-inch needle for quads or glutes. A 25-gauge, 5/8-inch needle works for smaller muscles or leaner individuals.
- Injecting needle (SubQ): A 25- to 27-gauge, 1/2-inch needle for belly or thigh fat.
- Alcohol swabs: For sterilizing the vial top and your skin.
- Sharps container: Never recap and reuse needles.
Step-by-Step Injection Process
Prep the Vial and Syringe
Wipe the rubber stopper of your testosterone vial with an alcohol swab. Attach your drawing needle to the syringe, then pull the plunger back to draw in about 0.5 mL of air. Insert the needle into the vial, flip the vial upside down, and push that air into the vial. This equalizes pressure inside the vial and makes drawing the oil much easier. Keep the needle tip below the fluid line and pull back on the plunger until you reach your prescribed dose.
If an air bubble enters the syringe, push the medication back into the vial and reposition the needle tip deeper into the fluid before drawing again. Small air bubbles won’t harm you, but they take up space and throw off your dose. Once you have the correct amount, remove the needle from the vial and swap it for your injection needle.
Choose and Clean Your Site
Clean the injection area thoroughly with a fresh alcohol swab using a circular motion and let it air-dry for a few seconds. Don’t blow on it or fan it, as that reintroduces bacteria.
Inject
For IM, insert the needle at a 90-degree angle in one smooth, firm motion. For SubQ, pinch a fold of skin and fat between your fingers and insert the needle at roughly a 45-degree angle into the pinched tissue. In both cases, push the plunger slowly. A slow, steady injection (10 to 15 seconds for most doses) lets the oil spread through the tissue gradually, which reduces soreness later. Rushing forces oil into a small pocket that pushes back against surrounding tissue.
Once the syringe is empty, wait a couple of seconds before withdrawing the needle smoothly at the same angle it went in. Apply light pressure with a clean cotton ball or gauze. You don’t need to massage the area.
Do You Need to Aspirate?
Aspiration, the practice of pulling back on the plunger to check for blood before injecting, used to be standard. It’s no longer recommended by the World Health Organisation or the Centers for Disease Control and Prevention. The reasoning: there are no large blood vessels at the standard injection sites, aspiration increases pain, and there’s no evidence it prevents adverse events. If your provider specifically instructs you to aspirate, follow their guidance.
Best Injection Sites
For Intramuscular Injections
The two most common IM sites are the outer thigh (vastus lateralis) and the ventrogluteal hip. The ventrogluteal is widely considered the safest IM site because it’s a thick muscle with fewer nerves and blood vessels than the traditional upper-outer glute.
To find the ventrogluteal site, place the palm of your opposite hand over the bony bump at the top of your thigh (the greater trochanter). Point your index finger toward the front of your hip bone (the anterior superior iliac spine) and spread your middle finger back toward the top of the hip crest. The injection goes into the center of the V shape formed by those two fingers. It sounds complicated the first time, but after one or two injections it becomes second nature.
For the outer thigh, the target is the middle third of the outer quadricep, roughly a hand’s width above the knee and a hand’s width below the hip.
For Subcutaneous Injections
The lower abdomen (at least one inch from the belly button), the mid-thigh, and the back of the upper arm all work well. These areas tend to have enough fat to cushion the injection. Stay at least one hand-width away from the kneecap when using the thigh.
Why Rotating Sites Matters
Injecting repeatedly into the same spot causes the tissue to build up scar tissue or lumps of hardened fat (lipohypertrophy). Both make future injections more painful and can interfere with absorption. Rotating between at least two or three sites, and alternating left and right sides, spreads the wear across more tissue.
A simple approach: keep a short log with the date, site, and side. Some people use a phone note, others write on a calendar. The format doesn’t matter as long as you’re not guessing. Over time, logging also helps you spot patterns, like one site that always gets more sore than others, so you can adjust.
Reducing Post-Injection Pain
Some soreness after pinning is normal, especially in the first weeks. This is called post-injection pain (PIP), and it usually comes from the oil irritating the tissue, the mechanical trauma of the needle, or tension in the muscle during injection. It typically peaks the next day and fades within two to three days.
A few things help significantly. First, relax the muscle. If you’re injecting your quad, sit down and let the leg go completely limp. If you’re clenching, the oil has nowhere to spread and the soreness will be worse. Second, inject slowly. Pushing the plunger over 10 to 15 seconds gives the muscle time to accommodate the oil instead of fighting it. Third, warm the vial beforehand by rolling it between your palms for a minute or two. Warmer oil is thinner and flows into tissue more easily.
Using the smallest gauge needle that still works for your oil and dose also helps. A 25-gauge needle creates less tissue trauma than a 23-gauge, though it takes slightly longer to push the oil through. If you’re consistently sore at one site, rotate away from it for a few weeks.
When Soreness Isn’t Normal
A hard, painless or mildly tender lump that appears a day or two after injection is often a sterile abscess: a buildup of fluid without infection. These typically resolve on their own within a few weeks. Warm compresses can help.
Signs that point to an actual infection are different and more urgent: worsening redness that spreads outward, increasing pain rather than fading pain, red streaks radiating from the injection site, fluid draining from the area for more than a couple of days, or fever and chills. These symptoms mean bacteria got introduced during the injection, and you need medical attention promptly.
The easiest way to prevent infection is also the most boring: clean the vial top every time, clean your skin every time, use a fresh needle every time, and never touch the needle tip with your fingers or set it down on an unsterile surface.