INJECTWISE
All learning
Guide · 8 min

Injection technique & site rotation

SubQ vs IM, needle choices, aspiration, and why rotating sites keeps scar tissue down.

SubQ vs intramuscular

Subcutaneous (subQ) goes into the fat layer just under the skin — common for peptides, GLP-1s, and HCG, using a short fine needle. Intramuscular (IM) goes deeper into muscle and is typical for oil-based compounds. The two use different needles, sites, and angles, so know which one a given compound calls for.

Needle choice

Oil-based IM shots are often drawn with a wider gauge (to pull thick oil) and injected with a finer one to reduce discomfort. SubQ injections use short insulin needles. A fresh, sharp needle every time hurts less and is more hygienic — never reuse.

Clean technique, step by step

The routine is the same every time — build the habit and it becomes automatic:

  • Wash your hands; swab the stopper and the injection site with alcohol and let both dry.
  • Draw your dose; tap out and expel air bubbles.
  • For IM, many people aspirate (pull back slightly) to confirm they are not in a vessel.
  • Inject smoothly and steadily, withdraw, and apply light pressure.
  • Dispose of the needle in a proper sharps container — never reuse.

Why rotation matters

Hitting the same spot repeatedly builds up scar tissue and can cause lumps, poor absorption, and pain. Rotating across available sites — and giving each one time to recover — keeps tissue healthy and absorption consistent. The site rotation tool logs where you last injected so you are not guessing.

💡The Site rotation tool colors each site by how recently it was used and suggests the most-rested spot next.

When something is off

Mild redness or a small bump can be normal. Spreading warmth, significant swelling, fever, or severe pain are not — those warrant medical attention. This guide is about technique and hygiene, not a substitute for a clinician.

Spreading redness/warmth, significant swelling, fever, or severe pain can signal an infection (e.g. an abscess or cellulitis). Get it looked at — do not wait it out.
Educational only — harm-reduction information, not medical advice.