The ideal injection sites include the deltoid, the stomach, or the thigh
These peptides are being explored for their role in supporting biological processes involved in tissue repair, inflammatory balance, and skin and gut health

Common side effects (affect 10-30% of users): Growth hormone-related peptides (CJC-1295, Ipamorelin, etc.): Water retention (mild, temporary) Joint pain (usually temporary adaptation) Carpal tunnel-like symptoms (rare) Numbness/tingling in extremities (rare) Increased hunger (GHRP-6, GHRP-2) Lethargy initially (body adjusting) Healing peptides (BPC-157, TB-500): Headaches (occasional, mild) Nausea (rare) Dizziness (rare) Increased body hair growth (TB-500) Injection-related: Site reactions (redness, minor pain) Bruising (improper technique) Infection risk (if sterility not maintained) Rare but possible: Blood sugar changes (monitor if diabetic) Prolactin increase (with some GH peptides) Tachyphylaxis (reduced effectiveness over time with some peptides) What's notably absent: No testosterone suppression No cardiovascular remodeling No liver stress No hormonal disaster No PCT required No infertility issues Long-term safety: Growth hormone peptides mimic natural pulses (safer than exogenous GH) Healing peptides have excellent long-term safety profiles No evidence of organ damage with proper use Can be used for extended periods Head-to-head safety comparison Hormonal disruption: Steroids: 10/10 severity (guaranteed shutdown) Peptides: 1/10 severity (minimal hormonal impact) Cardiovascular risk: Steroids: 8/10 severity (significant risk increase) Peptides: 2/10 severity (minimal concerns) Liver toxicity: Steroids: 7/10 severity (oral steroids especially) Peptides: 0/10 severity (no liver impact) Reversibility of side effects: Steroids: 5/10 (some permanent damage possible) Peptides: 9/10 (almost everything reverses) Need for ancillary drugs: Steroids: Extensive (AI, SERM, hCG, PCT drugs, BP meds) Peptides: Minimal (maybe vitamin B6 for prolactin if needed) The safety profile of peptides is vastly superior

Other theoretical risks researchers have noted include oxidative metabolites
In short, the difference between oral supplementation and injection is that an injection will provide a higher dose of B12 at regular intervals, whilst oral supplements have a lower dosage and can be taken every day