Common Mistakes

The errors that cause real harm — with solutions

⚠️ The Mistakes That Matter Most

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Reusing needles What happens: Blunted tip tears tissue instead of piercing. Pain increases. Micro-damage accumulates into lipodystrophy (permanent scar tissue). Infection risk increases with every reuse. Solution: New needle every time. 100 insulin syringes cost less than £8. This is not a cost issue.

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Swabbing the injection site after injecting instead of before What happens: Alcohol after injection pushes surface bacteria inward through the still-open needle track, and rubs the peptide away from the injection site. Solution: Swab before, apply gentle pressure after (no rubbing).

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Not waiting for the alcohol swab to dry What happens: Wet alcohol injected into tissue burns painfully and can cause local irritation. On the vial top — wet alcohol injected into the vial can affect the peptide. Solution: Count 10 seconds after swabbing. Every time.

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Injecting directly onto the powder during reconstitution What happens: The force of water hitting the fragile lyophilised peptide structure damages it. Reduced potency, sometimes significant. Solution: Always aim the needle at the glass wall, not the powder. Let water run down the side.

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Using the wrong reconstitution water What happens: Tap water contains bacteria and minerals. Plain sterile water has no preservative — rapid bacterial growth in multi-dose vials. Saline can cause peptide precipitation in some compounds. Solution: Bacteriostatic water only for any multi-dose vial.

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Maths errors in dose calculation What happens: Injecting 10× the intended dose is possible when concentrations are miscalculated. For compounds like IGF-1 LR3, this can cause acute hypoglycaemia. Solution: Use the calculator on this page. Calculate before touching a needle. Double check. Never do maths in your head at the time of injection.

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Not rotating injection sites What happens: Repeated injection into the same spot causes lipodystrophy — permanent fat cell damage and scar tissue. The area becomes hard, less sensitive, and absorbs peptide less effectively. Solution: Map out rotation zones and keep a log. Never return to the same 1cm spot within 7–10 days.

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Freezing reconstituted peptides What happens: Freeze-thaw cycles cause ice crystals to form and disrupt the peptide structure. Degraded potency. Solution: Reconstituted peptides live in the fridge, not the freezer. Lyophilised powder can be frozen — reconstituted solution cannot.

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Shaking the vial to mix What happens: Vigorous shaking introduces air bubbles, causes frothing, and can mechanically degrade the peptide chain. Solution: Roll gently between palms. If the powder is not dissolving, wait — it will. Never shake.

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Ignoring early warning signs at injection sites What happens: Redness, warmth, swelling, or pain that persists more than 24 hours at an injection site indicates a possible infection (cellulitis). Untreated cellulitis spreads and requires antibiotic treatment — sometimes hospitalisation. Solution: If a site is red, warm, swollen, or increasingly painful at 24 hours — see a doctor. Do not inject at that site again until fully healed.

If you see any of these — seek medical attention immediately: Injection site that is spreading redness (cellulitis), fever above 38°C following injection, red streaks extending from injection site (lymphangitis), severe pain disproportionate to injection, abscess formation (fluctuant swelling with pus). These are rare but serious. A peptide protocol is not worth delaying treatment for a genuine infection.

The bottom line: The vast majority of peptide injection complications are preventable with consistent sterile technique. The checklist at the top of this page, followed every time, eliminates most risk. The people who develop infections are almost always the people who started cutting corners on steps that felt unnecessary when everything was going well. Everything on this page exists because something went wrong for someone who skipped it.