How to inject peptides

Most research peptides are dosed subcutaneously (SubQ) with a small insulin syringe. IM injection is only necessary for a few specific compounds.

This guide describes general sterile injection practice. It is not a prescription and does not replace guidance from a licensed clinician who knows your medical history.

What you need

Reconstituted peptide vial (see the reconstitution guide)
29–31 gauge insulin syringe, 0.5 ml, ½ inch (12.7 mm) for SubQ
23–25 gauge, 1–1.5 inch syringe for IM (glute or delt)
Alcohol swabs (70% isopropyl)
Sharps container

Needle gauge, plain-English

Higher gauge = thinner needle. A 30g insulin pin is barely felt going in. Never re-use a needle: it dulls immediately and dulled needles hurt and bruise.

Subcutaneous technique (step by step)

Wash your hands. Wipe the vial's rubber stopper and the injection site with a fresh alcohol swab. Let both air-dry.
Draw your dose into the insulin syringe. Flick out bubbles and push the plunger until a bead forms on the needle tip.
Pinch about an inch of subcutaneous fat on your abdomen (two inches from the navel), outer thigh, or love handle.
Insert the needle at 90° into the pinched fold. At ½ inch you're in the SubQ layer, not muscle.
Depress the plunger slowly and evenly over 3–5 seconds.
Withdraw the needle straight out. Apply light pressure with a fresh swab if there's any blood.
Cap and drop the syringe directly into your sharps container. Never re-cap by pushing the cap onto a needle you're holding — set the cap down and slide the needle in.

Site rotation

Rotate at least 1 inch from your last injection site each time. A simple pattern: left abdomen Monday, right abdomen Tuesday, left thigh Wednesday, right thigh Thursday, repeat. Rotation prevents lipohypertrophy (lumpy scar tissue) and reduces bruising.

When bleeding or bruising happens

A little blood means you nicked a surface capillary. Apply pressure for 30 seconds. Bruises are cosmetic and fade in a few days. Persistent hard lumps mean you're hitting the same spot too often — rotate wider.

Sharps disposal

Use an FDA-cleared sharps container or a rigid, puncture-resistant plastic container with a screw-top lid (e.g., an empty laundry-detergent bottle). Most US pharmacies accept full sharps containers for disposal. Never put loose needles in household trash.

Signs to stop and see a doctor

Spreading redness, warmth, or pus at an injection site (possible infection)
Fever above 38 °C / 100.4 °F after injecting
Difficulty breathing, hives, or facial swelling (allergic reaction — call emergency)
Severe or persistent abdominal pain (pancreatitis risk with GLP-1s)