Peptide Injection Sites: Where to Inject, Rotation and Angle

Each approved product's Instructions for Use defines its own sites. They overlap, but they are not identical, and the differences are deliberate.

For the GLP-1 drugs the choice among the three areas does not change how much drug reaches the bloodstream: both the Ozempic and Mounjaro labels state that similar exposure is achieved in the abdomen, thigh or upper arm. The Vyleesi label likewise reports that abdomen versus thigh had no significant effect on systemic exposure. Site choice is about comfort, reach and skin health, not potency.

Abdomen

The most-used site and the only one on the Egrifta SV label. The labels that mention the navel put a 2-inch (5 cm) exclusion zone around it. That leaves a wide band of skin on either side and below, which makes the abdomen the easiest area to rotate within.

Thigh

The Vyleesi instructions specify the front of the thigh. It is easy to see and reach yourself, which is why both self-injection labels that restrict sites still include it.

Back of the upper arm

Ozempic lists the upper arm; the Mounjaro and Ozempic syringe instructions specify that the back of the upper arm should be injected by another person. It is hard to pinch a skin fold and hold an angle there one-handed.

Where not to inject

• Within 2 inches of the belly button
• Scar tissue, bruises, or skin that is irritated, sore, red or hard
• Areas with lumps from previous injections
• Through clothing
• Into a muscle or vein when the label says subcutaneous

Every label on this page tells patients to rotate. The Mounjaro instructions add the useful detail: you may use the same area of the body each week, but choose a different spot within it, to reduce the risk of lipodystrophy (pits or thickened skin) and localized cutaneous amyloidosis. Egrifta SV ties rotation to injection-site reactions, which occurred in 25% of patients in its trials versus 14% on placebo.

The FITTER injection-technique recommendations explain why this matters beyond comfort: lipohypertrophy is a frequent complication of repeated injection, it distorts absorption, and injections should not be given into these lesions. Correct rotation helps prevent them.

If you also inject insulin, the Ozempic and Mounjaro labels allow both in the same body area, but not right next to each other, and never mixed in the same injection.

The aim of a subcutaneous injection is to land in fat, not muscle. FITTER's headline recommendation is that the shortest needles, the 4 mm pen needle and the 6 mm syringe needle, are safe, effective, less painful and should be the first-line choice in all patient categories. The labels then specify angle and pinch for their own devices.

The pattern is consistent: a longer needle (like the ½-inch Egrifta needle) is used with a pinched fold so it stays out of muscle; the Ozempic syringe uses a 45-degree angle into a pinch for the same reason. Reading the dose on the barrel is a separate skill, covered in the syringe measurement guide. To turn a milligram dose into the units you draw, use the mg to mL converter.

This is the common sequence across the Ozempic, Mounjaro, Egrifta SV and Vyleesi instructions. Where your product's own Instructions for Use differ, follow those.

1. Wash your hands with soap and water.
2. Check the product, dose and (for a vial) that the solution is clear.
3. Choose a site from the ones your label allows, a new spot from last time.
4. Clean the site with an alcohol pad and let it dry.
5. Pinch a skin fold if your device's instructions call for it.
6. Insert the needle at the angle your instructions give (for example 45 degrees for the Ozempic syringe, 90 degrees for the Egrifta SV needle).
7. Push the plunger or button slowly and fully; hold as instructed.
8. Withdraw the needle, do not recap it, and put it in a sharps container.

Never reuse or share a needle, syringe or pen, even with a new needle attached; the labels flag infection transmission as the reason.

Sermorelin has no current US label to consult. It was approved as Geref (sermorelin acetate, EMD Serono, 1997) and is now listed as discontinued, with FDA noting it was not withdrawn for safety or effectiveness reasons. Today it is supplied mainly through compounding pharmacies, which do not issue FDA-approved instructions.

The closest approved reference is another GHRH analogue, tesamorelin, whose Egrifta SV label specifies subcutaneous injection into the abdomen only, rotated across the abdomen and kept 2 inches from the navel. That is a useful analogy for technique, not a label for sermorelin. A prescriber who compounds sermorelin should specify the site and technique. Dose arithmetic is on the sermorelin dosage page and the sermorelin calculator.

PT-141 injection site

PT-141 is bremelanotide, so it is the one research name here with a real label. Vyleesi is injected subcutaneously into the abdomen or the front of the thigh only, avoiding 2 inches around the navel, at least 45 minutes before anticipated sexual activity. See PT-141 dosage for women for the label dose and limits.

TB-500 injection site

There is no label. Online advice often says to inject TB-500 near an injury. Nothing in an approved label supports that, and FDA's compounding review states it has not identified any human exposure data for products containing the thymosin beta-4 fragment sold as TB-500. More on the TB-500 dosage page.

CJC-1295 injection site

No label either. FDA's compounding review notes serious adverse events associated with CJC-1295, including increased heart rate and a systemic vasodilatory reaction, and says available clinical data are limited. See CJC-1295 dosage.

AOD-9604 injection site

FDA's review says it has no, or only limited, safety information for AOD-9604, so there is no basis for a site recommendation beyond general subcutaneous technique.

For all three research compounds, the honest summary is that site guidance online is borrowed from the approved labels above. Choosing the abdomen or thigh and rotating is reasonable technique; it does not make an unapproved compound safer.

Calcitonin salmon (Miacalcin) is one of the older peptide drugs and one of the few that allows two routes: subcutaneous or intramuscular. The label sets the route by volume rather than providing a body map: if the volume exceeds 2 mL, intramuscular injection is preferable and the dose should be spread across multiple sites. Local inflammatory reactions at the injection site were reported in about 10% of patients. The label also tells patients to use sterile technique and dispose of needles properly. Where to place a subcutaneous dose is something the prescriber or pharmacist should show you for this product.