Retatrutide is a subcutaneous (under-the-skin) weekly injection. This page covers where to inject, how to do it properly, what equipment you need, and the increasingly common questions about oral or nasal-spray forms — almost none of which exist.
Where to inject retatrutide
Three approved subcutaneous injection zones, all with enough fat to absorb the drug slowly for weekly-dose pharmacokinetics:
- Abdomen. At least 2 inches away from the navel. Cover a rotating grid — e.g., upper left, upper right, lower left, lower right, repeating over 4 weeks. Most common site.
- Thigh (front or outer upper). Avoid the inner thigh (more blood vessels). Works if you want to keep abdomen untouched.
- Upper arm (back, triceps area). Difficult to do alone for most people. Fine if you have a helper.
Rotate sites weekly to prevent lipohypertrophy — a lumpy fat build-up that can mess with absorption. Never inject into a bruise, broken skin, or a tender area. Do not inject into muscle (intramuscular) — absorption profile is different and not validated for weekly dosing.
How to inject retatrutide: step by step
- Bring the vial to room temperature (15 min). Cold injections sting; room-temp is smoother.
- Wash your hands. Soap and water, 20 seconds. Dry completely.
- Sanitize the vial stopper. Alcohol swab, let air dry for 5 seconds.
- Draw your dose. Use the units calculated in the dosing calculator based on your vial concentration. Pull plunger back to the air volume equal to your draw, inject air into vial (prevents vacuum), invert, draw solution to the correct line. Flick out bubbles.
- Sanitize the injection site. Alcohol swab the spot. Let air dry. (Wet alcohol + needle = sting.)
- Pinch. Gently pinch an inch of skin between thumb and forefinger.
- Insert the needle. 45° to 90° depending on how much subcutaneous fat you have (leaner → 45°; more fat → 90°). Insert smoothly.
- Inject slowly. Depress plunger over 3–5 seconds. Slow injection reduces burn and tissue stress.
- Hold and withdraw. Leave the needle in for 3 seconds after the plunger bottoms out. Withdraw at the same angle you inserted.
- Dispose of the needle. Never recap. Drop directly into a sharps container.
- Record. Date, dose, site, any side effects. A simple note in your phone.
Injection site rotation schedule
| Week | Site | Why |
|---|---|---|
| 1 | Upper-left abdomen | Start with non-dominant side |
| 2 | Upper-right abdomen | Opposite quadrant |
| 3 | Lower-left abdomen | Descend |
| 4 | Lower-right abdomen | Complete the grid |
| 5 | Left thigh front | Switch region to let abdomen recover |
| 6 | Right thigh front | Opposite leg |
| 7 | Left upper arm (back) | Third region |
| 8 | Right upper arm (back) | Return to abdomen next week |
Common injection mistakes
- Injecting cold vial directly. Sting is much worse. Warm to room temp.
- Reusing needles. Each injection uses a fresh sterile needle. Re-using dulls the needle and contaminates it.
- Injecting into alcohol. Let the swab fully air dry before needle insertion.
- Same site every week. Leads to lipohypertrophy and erratic absorption. Rotate.
- Rushing the push. Fast plunger = more burn, more tissue damage, occasional back-flow. Slow over 3 seconds.
- Pulling the needle before the hold. Wait 3 seconds after the plunger bottoms out, or you lose a portion of the dose as back-flow.
Is there oral retatrutide?
No. Retatrutide has not been developed in any oral form. The peptide structure is destroyed by stomach enzymes, which is why essentially all long-chain peptide drugs are injectable. Eli Lilly is investigating orforglipron, an oral small-molecule GLP-1 agonist — but orforglipron is a different drug entirely, and its trials show weight loss (~15%) in the semaglutide-injectable range, not the retatrutide range.
If you see "oral retatrutide," "retatrutide pill," or "retatrutide sublingual" advertised: it is either a scam or a different drug mislabeled. No legitimate source sells an oral retatrutide product.
Is there a retatrutide nasal spray?
No. Peptide drugs generally cannot be efficiently delivered nasally — mucosal absorption is erratic and insufficient for weekly-dose pharmacokinetics. No Eli Lilly nasal retatrutide program exists. Nasal sprays marketed as "retatrutide" online are at best mislabeled and at worst scams.
Retatrutide pen
There is no commercial retatrutide pen because there is no FDA-approved retatrutide. When and if retatrutide launches, Eli Lilly will likely offer a single-use pen similar to the Mounjaro KwikPen and Zepbound pen. In the meantime:
- Clinical trial retatrutide is typically provided in single-use pens or pre-filled syringes.
- Compounding pharmacy retatrutide may be dispensed in multi-dose vials or pre-filled syringes.
- Research peptide retatrutide always comes as powder vials requiring reconstitution.