Choosing an Injection Site
Rotate between abdomen, thigh, and upper arm each dose.
- 3: Approved sites (abdomen, thigh, upper arm)
- ~2.5 cm: Min. spacing within site (from last puncture)
- 4: Sites tracked (abdomen split L/R)
- 4 wk: Rotation window (before site repeats)
Why rotation matters
Repeated same-spot injections irritate tissue over time.
Picking today's site
Choose the zone rested longest since last use.
Avoid any site used within the last week.
Skin Pinch and Needle Angle
A pinched fold and correct angle keep the dose subcutaneous.
- 90°: Standard pen angle (perpendicular into fold)
- 45°: Thin-tissue alternative (when pinch is shallow)
- 4–8 mm: Needle length (pens) (typical GLP-1 pen needles)
- after insert: Fold release timing (not before)
Building the fold
Pinch skin gently between two fingers, not muscle.
Setting the angle
Steeper angle reduces risk of intramuscular delivery.
Angles below 45° risk shallow, intradermal dosing.
Injection Delivery and Hold Time
Steady plunger pressure and a brief hold ensure full dose delivery.
- ~5 sec: Plunger press time (steady, not rushed)
- 6–10 sec: Hold after dose (before withdrawing needle)
- same as entry: Withdrawal angle (straight back out)
- no rub: Post-injection care (light pressure only)
Steady delivery
Even pressure avoids leakage and tissue trauma.
Hold before withdrawal
Counting seconds prevents medication backflow.
Pulling out too fast can leak part of the dose.
Tracking Site Use Across Weeks
A simple log prevents accidentally reusing the same spot.
- 10 wk: Log entries kept (rolling history window)
- 4: Sites in rotation (abdomen L/R, thigh, arm)
- ≥3 wk: Safe threshold (since last use of a site)
- app or notebook: Tracking method (date + site each dose)
Reading the heat-map
Warm colors mean recently used, avoid those spots.
Building a habit
Log the site immediately after each injection.
A written log beats memory for spotting patterns.
Technique Outcomes: Bruising, Lipodystrophy, Reactions
Good technique and rotation sharply cut injection-site problems.
- higher: Lipodystrophy risk, poor rotation (repeated same-spot dosing)
- lower: Bruising, correct angle (clean subcutaneous placement)
- ~5–10%: Reaction risk, good technique (mild, transient redness)
- ~30–50%: Reaction risk, poor technique (bruising, lumps, irritation)
Why lipodystrophy happens
Fat tissue thickens under repeated identical injection points.
Compounding effect
Angle and rotation together determine long-term skin health.
Combining rotation with correct angle minimizes almost all site reactions.