04
Injection Sites
SubQ and IM — every site, fully mappedFront View — SubQ Sites
Back View — Additional SubQ Sites
Abdomen
Primary Site
The best SubQ site for most people and most peptides. Large surface area, good subcutaneous fat depth, easy to see and access, excellent absorption. The go-to site for daily injections.
📍 Stay at least 2 inches from the navel in all directions
📍 Use a 2–3 inch square zone on each side — 8 zones total with left/right and quadrants
📍 Avoid the waistband and beltline area — clothing friction irritates injection sites
📍 45° angle with skin pinch — or 90° if you have adequate subcutaneous fat depth
📍 Best site for GLP-1 peptides (Semaglutide, Tirzepatide) — pharmaceutical standard
Outer Thigh
SubQ / IM
Excellent rotation site when abdomen sites need rest. Accessible for self-injection, good fat layer in most people. Works for both SubQ and IM depending on needle length used.
📍 Use the outer middle third — the lateral quadriceps area
📍 Not the inner thigh (femoral vessels run close) — outer only
📍 Not too high (hip joint) or too low (knee joint) — middle third only
📍 Pinch skin before inserting at 45° for SubQ; no pinch at 90° for IM
📍 Lean muscle site — may be less comfortable than abdomen for large volumes
Outer Upper Arm
Secondary SubQ
Good rotation option but harder to self-inject — pinching the skin here with one hand while injecting with the other is awkward. Works well if you have assistance, or use a no-pinch technique.
📍 Lateral deltoid area — outer mid-upper arm, halfway between shoulder and elbow
📍 No-pinch technique at 90° works here — or use a dart-throw motion
📍 Avoid the inner arm (basilic vein and brachial artery run close)
📍 Less fat than abdomen — use a shorter needle and be precise
📍 Easier with an auto-injector device if available
Lower Back / Flanks
Rotation Site
The love handle and lower back area. Often overlooked but gives excellent rotation away from abdomen when that area is overused. Usually has good subcutaneous fat depth. Requires some flexibility to reach.
📍 Side/flank area alongside the hip — not the spine itself (never inject near spine)
📍 Good reach by twisting slightly — or use a longer syringe for easier access
📍 Often more subcutaneous fat than thigh — comfortable injection
📍 Stay lateral — 3+ inches from the spine at minimum
Tricep / Back of Arm
Secondary SubQ
Posterior upper arm — the tricep area. Used by experienced self-injectors as an additional rotation site. Requires assistance or significant arm flexibility to reach comfortably.
📍 Posterior lateral aspect — not the inner arm
📍 Usually less subcutaneous fat — lean individuals may find this uncomfortable
📍 Good site when abdomen and thigh are on rest rotation
📍 Easier with assistance from a partner
Abdomen Rotation Zones
Use This System
Divide your abdomen into 8 zones — 4 on each side of the navel. Rotate through all 8 in sequence before returning to Zone 1. This gives 7–10 days between injections at the same spot.
📍 Zone 1: Left upper (10 o'clock from navel)
📍 Zone 2: Right upper (2 o'clock from navel)
📍 Zone 3: Left middle (9 o'clock from navel)
📍 Zone 4: Right middle (3 o'clock from navel)
📍 Zones 5–8: Lower abdomen mirror of 1–4
IM injection is not required for most peptides. The vast majority of peptides — BPC-157, TB-500, Semaglutide, Ipamorelin, CJC-1295, Epitalon, and most others — work perfectly via SubQ injection. IM is used for specific compounds (Cerebrolysin, some TB-500 protocols) or by personal clinical preference. If you are new to injection, start with SubQ. Only move to IM if your specific compound or physician protocol requires it.
IM Sites — Front View
IM Sites — Back View
Vastus Lateralis ★ Best
IM — Self-Inject
The outer thigh muscle — the safest and most accessible IM injection site for self-injection. Large muscle mass, no major vessels or nerves in the injection zone, easy to see what you are doing. The recommended IM site for anyone new to IM injection.
📍 Outer middle third of the thigh — not inner, not front (quadricep belly), outer lateral
📍 90° angle, no skin pinch — firm insertion into the muscle
📍 Aspirate before injecting — pull back slightly, confirm no blood before depressing
📍 25–27G, 1 inch needle for most body types — 1.5 inch for larger individuals
📍 Inject slowly — muscle tissue has more nerve endings than subcutaneous fat
Deltoid (Shoulder)
IM — Small Volumes
The lateral deltoid muscle — used clinically for small-volume injections (under 1ml). Good absorption. Easy to access with practice. Not suitable for large volumes — discomfort increases significantly above 1ml.
📍 Lateral aspect only — the outer shoulder muscle, not front or rear
📍 2–3 finger-widths below the acromion (bony shoulder tip)
📍 Maximum 1ml volume — larger volumes cause post-injection muscle soreness
📍 25G, 1 inch needle — shorter needles can deposit in fat rather than muscle
📍 Aspirate before injecting — radial nerve and brachial artery in proximity
Gluteus — Upper Outer Only
IM — Assistance Preferred
The traditional clinical IM site — large muscle, comfortable for larger volumes. The catch: the sciatic nerve runs close to the lower and inner portions. The upper outer quadrant only is safe. Difficult to self-inject accurately — assistance strongly preferred.
📍 Divide the buttock into 4 quadrants — inject ONLY in the upper outer quadrant
📍 The ventrogluteal site (upper hip, not buttock) is safer and preferred by many clinicians
📍 Never inject in the lower or inner quadrants — sciatic nerve risk is real and serious
📍 1.5–2 inch needle required for adequate depth in most adults
📍 Aspirate before injecting — superior gluteal artery proximity
Tricep (Posterior Upper Arm)
IM — Small Volumes
The posterior upper arm. Less commonly used but a useful rotation site for small-volume IM compounds like Cerebrolysin. Requires assistance or significant flexibility. Smaller muscle — volumes above 1ml are uncomfortable.
📍 Posterior lateral surface — mid-upper arm, outer aspect
📍 Avoid the inner arm — ulnar nerve and brachial vessels
📍 Maximum 1ml — small muscle belly limits comfortable volume
📍 25–27G, 1 inch — shorter than glute or thigh
📍 Used clinically for small-volume Cerebrolysin injections
⚠ Critical IM safety — always aspirate before injecting. After inserting the needle into muscle, pull the plunger back slightly before injecting. If blood appears in the syringe — you are in a vessel. Withdraw immediately, apply pressure, use a fresh syringe and new site. No blood = safe to inject slowly. This step is non-negotiable for IM injection.
Never inject into any of the following. These are not suggestions — they are sites where injection causes real harm: infection that spreads rapidly, vascular injection (systemic adverse effects), nerve damage, or permanent scarring. The list below covers the sites that cause the most preventable harm in self-injection practice.
Inner Thigh
Never — Vascular Risk
The femoral artery and great saphenous vein run close to the inner thigh surface. Accidental intravascular injection here is dangerous — rapid systemic distribution of the entire dose. Fat distribution in the inner thigh is also poor for SubQ absorption.
⚠ Femoral artery — one of the body's major arteries, close to inner thigh surface
⚠ Accidental arterial injection causes immediate severe systemic reaction
⚠ Use the outer lateral thigh only — maintain a clear margin from the inner surface
Lower / Inner Gluteal Region
Never — Nerve Risk
The sciatic nerve — the largest nerve in the body — exits the pelvis through the lower portion of the gluteus maximus. Injection into or near the sciatic nerve causes immediate electric pain, potential permanent nerve damage, and foot drop.
⚠ Sciatic nerve injury is one of the most devastating self-injection complications
⚠ If you use glute IM: upper outer quadrant ONLY — no exceptions
⚠ The vastus lateralis is safer and equally effective — use it instead
Anywhere Near a Joint
Never — Infection Risk
Knees, elbows, hips, ankles, wrists. Joints have poor blood supply to fight infection, and infection introduced near a joint can spread into the joint space (septic arthritis) — a serious complication requiring hospitalisation and sometimes surgery.
⚠ Septic arthritis is a medical emergency — joint infections spread rapidly
⚠ Maintain at least 3 inches clearance from all joint spaces
⚠ Knee and elbow areas — never, under any circumstances
Visible Veins
Never — IV Risk
Injecting near or into a visible vein risks intravenous delivery — the entire dose enters the bloodstream instantly. This is not the intended pharmacokinetic profile for SubQ or IM peptides and can cause acute adverse effects.
⚠ If you see a vein at your intended site — move at least 2 inches away
⚠ Basilic vein on inner arm, cephalic vein on outer arm — avoid injection nearby
⚠ For IM: aspirate before every injection to confirm you are not in a vessel
Infected, Bruised, or Irritated Skin
Never — Spreads Infection
Injecting through compromised skin drives surface bacteria into deeper tissue. A minor surface infection becomes a deep tissue infection or abscess. Bruised tissue has disrupted blood supply and will absorb peptide poorly even without infection risk.
⚠ Any redness, warmth, or tenderness at a site — rest it for minimum 7 days
⚠ Bruising — wait until fully resolved before returning to that site
⚠ Active rash, dermatitis, eczema — avoid that area entirely
Scar Tissue and Moles
Avoid
Scar tissue has poor vascularisation — peptide absorption is unreliable and slow. Moles and birthmarks should not be punctured — disruption can cause irritation, potential changes, and unnecessary discomfort. Both are easy to avoid with good site selection.
⚠ Map your moles and marks before establishing your rotation zones
⚠ Surgical scars — avoid for at least 12 months post-surgery, longer if keloid tendency
⚠ Existing lipodystrophy sites — rest until fully resolved (4–6 weeks minimum)
Site Rotation — Why It Matters and How to Do It
Injecting into the same spot repeatedly causes lipodystrophy — localised fat cell damage and scar tissue formation. Once established, scar tissue absorbs peptides poorly, reducing the effectiveness of every subsequent injection at that site. It can also become permanent. The solution is simple: never return to the same 1cm spot within 7–10 days.
✓ Rotation System That Works
Divide your abdomen into 8 zones (4 each side). Rotate: left upper → right upper → left middle → right middle → left lower → right lower → return. Add thigh left → thigh right between rounds. Write the date on each used zone or keep a simple injection log. Never rush back to a favourite site.
⚠ Signs You Need to Rest a Site
Hard lumps under the skin — fat cell damage. Visible indentations — established lipodystrophy. Consistently more painful than other sites — developing scar tissue. Skin thickening at the site. Any of these: rest that area for 4–6 weeks minimum and consider speaking to a physician if it does not resolve.