All four major weekly GLP-1 injectables — Wegovy (semaglutide), Ozempic (semaglutide), Zepbound (tirzepatide), and Mounjaro (tirzepatide) — share the same three FDA-approved subcutaneous injection sites: abdomen, front of thigh, and back of upper arm. The label instruction is identical across all four: rotate sites with each dose. Repeatedly injecting the same spot causes lipohypertrophy — thickened, rubbery fat tissue under the skin that absorbs the drug erratically. The downstream effect is erratic appetite suppression, plateaued weight loss, and inconsistent A1c control on diabetes indications. This cheat sheet maps the approved sites, gives an 8-week rotation example, and lists the technique mistakes that derail absorption.
Approved injection sites
| Site | Detailed location | Notes |
|---|---|---|
| Abdomen | Anywhere on the front of the belly, at least 2 inches (5 cm) away from the navel in any direction. Avoid the waistband area where clothing rubs. | Most commonly used site. Easy one-handed self-injection. Absorption is generally consistent. Avoid scars from prior surgeries. |
| Front of thigh | Middle third of the thigh, between the top of the knee and the hip crease. Use the outer-front quadrant, not the inner thigh. | Good fallback when the abdomen is sore. Self-inject sitting down with the leg relaxed. Slightly slower absorption than abdomen in some users. |
| Back of upper arm | Fleshy area on the back of the upper arm, halfway between the shoulder and elbow, over the triceps. | Usually requires a helper, because pinching the skin one-handed on your own arm is awkward. Skip this site if you live alone and have no consistent helper. |
Label sources: Wegovy DailyMed SetID ee06186f-2aa3-4990-a760-757579d8f77b; Ozempic SetID adec4fd2-6858-4c99-91d4-531f5f2a2d79; Zepbound SetID 487cd7e7-434c-4925-99fa-aa80b1cc776b; Mounjaro SetID d2d7da5d-ad07-4228-955f-cf7e355c8cc0. All four labels list the abdomen, thigh, and upper arm as the only approved sites, and all four instruct the user to rotate with each weekly injection.
Example 8-week rotation schedule
The goal is to never reuse the exact same spot within 4 weeks, and ideally to keep at least 2 inches (5 cm) between consecutive injections at the same site. Pick a memorable pattern; a written log on the pen box works for most people.
| Week | Site | Specific spot |
|---|---|---|
| 1 | Abdomen | Upper right, 2–3 inches right of and above the navel |
| 2 | Front of thigh | Right leg, middle of the thigh |
| 3 | Back of upper arm | Right arm, triceps area |
| 4 | Abdomen | Upper left, 2–3 inches left of and above the navel |
| 5 | Front of thigh | Left leg, middle of the thigh |
| 6 | Back of upper arm | Left arm, triceps area |
| 7 | Abdomen | Lower right, 2–3 inches right of and below the navel |
| 8 | Abdomen | Lower left, 2–3 inches left of and below the navel |
After week 8, restart at week 1. Each abdominal quadrant gets one injection per 8-week cycle, and each thigh and arm gets one. If you skip the upper arms (no helper), substitute additional abdominal quadrants and use both thighs each cycle — just keep 2 inches between any two consecutive abdominal injections.
Why same-spot injection is bad
- Lipohypertrophy — the main reason to rotate. Repeated injections into the same patch of subcutaneous fat cause lump-like fatty thickening that absorbs drug erratically — sometimes slower than normal tissue, sometimes faster. The clinical effect is unpredictable appetite suppression and uneven weight-loss progress dose to dose.
- Injection-site reactions get worse with repetition. Red, itchy, raised welts at the injection site are listed as common adverse reactions across all four GLP-1 labels. Rotating sites lets each spot heal between exposures.
- Bruising and induration build up. Repeatedly piercing the same square inch breaks small capillaries faster than they heal, leaving persistent bruises and hard nodules.
- Rare skin breakdown and necrosis. Case reports in long-term insulin users with severe lipohypertrophy plus continued same-spot dosing describe local skin necrosis — a mechanism plausible for any chronic subcutaneous injection.
- Absorption variability undermines trial-grade dose-response. Pivotal trials (STEP, SURMOUNT, SUSTAIN, SURPASS) enrolled patients who rotated sites per protocol. Reusing one spot is off-label technique.
Technique quick facts
- Bring the pen to room temperature for 15–30 minutes before injecting. Cold fluid stings far more on the way in. Do not microwave or run under hot water.
- Pinch up a fold of skin between thumb and forefinger; insert the needle straight in at 90 degrees. The pinch lifts subcutaneous fat away from underlying muscle and keeps the injection where it belongs.
- Hold the needle in for 5–10 seconds after pressing the pen button. Withdrawing too quickly leaves part of the dose in the needle hub and on the skin surface.
- Do not massage or rub the site after injection. Rubbing speeds local absorption inconsistently and increases bruising. A clean cotton ball with light pressure is fine if you bleed.
- Keep 2 inches (5 cm) between any two consecutive injections, even within the same broad site. “Abdomen” is a region, not a spot.
- Use a new pen needle every time on multi-dose pens (Wegovy single-use pens come with the needle attached). Reusing dulls the tip and raises tissue trauma and infection risk.
- Log each injection — date, site, quadrant — on the pen box or in a phone note. Unlogged rotators drift back to favorite spots.
Common mistakes
- Injecting through clothing. Even thin fabric drags bacteria into the puncture and can deflect the needle off the right angle. Always inject into clean, bare skin.
- Injecting into stretch marks, tattoos, moles, or scars. These tissues have altered vascularity and unpredictable absorption. Pick a clear patch of normal skin.
- Reusing needles to save money. Dulled tips tear tissue, raise pain, and concentrate damage in whatever spot you favor — compounding the lipohypertrophy risk.
- Injecting cold straight from the fridge. Stings sharply and adds nothing clinically. Pull the pen 20 minutes before you plan to inject.
- Skipping the upper arm because it's “hard”, then overusing the abdomen. If a helper is unavailable, alternate thighs and abdominal quadrants instead. Don't collapse the rotation onto one square inch of belly.
Related on Weight Loss Rankings
- All cheat sheets — the full library of dosing, missed-dose, sick-day, and titration references.
- Wegovy Dose Ladder Cheat Sheet — the 17-week titration schedule that pairs with this rotation guide.
- Ozempic Missed Dose Cheat Sheet — the 5-day rule and restart protocol for skipped weekly doses.
- GLP-1 Side Effect Timeline tool — what to expect at each dose step, including injection-site reactions and when they typically resolve.