Common (>10% users):

• Hunger surge post-injection (especially fasted) — meaningful, not subtle, drives food-seeking behavior. The most reliably-reported acute effect.
• Mild water retention / edema (puffy hands, face, ankles) — GH-mediated renal sodium retention; possibly compounded by aldosterone elevation; generally larger than with ipamorelin.
• Mild cortisol-related subjective effects — slight wired feel, slightly disturbed sleep onset, slight low-grade anxiety. Variable by user.
• Mild headache (especially first 1-2 weeks) — GH-induced intracranial fluid shifts.

Less common (1-10%):

• Injection site reactions (redness, transient swelling, itch) — cosmetic; sometimes more pronounced than with ipamorelin.
• Carpal-tunnel-like paresthesias (numbness, tingling in hands) — GH-related fluid shift; resolves on dose reduction or discontinuation.
• Lethargy / grogginess — more reported than with ipamorelin; cortisol-spillover hypothesis.
• Vivid dreams / sleep disturbance — bidirectional (some users report deeper sleep, others more fragmented).
• Mild GI effects — nausea, increased GI motility, sometimes loose stools (gut ghrelin agonism).
• Glucose modulation — fasting glucose, fasting insulin, HbA1c can shift upward in susceptible individuals. Pulsatile dosing limits magnitude vs. MK-677, but additive cortisol elevation worsens the metabolic profile relative to ipamorelin.
• Prolactin elevation — modest, generally asymptomatic, but in susceptible users may produce mild gynecomastia-spectrum effects, libido changes, or galactorrhea (rare).

Rare-serious (<1% but worth knowing):

• Sustained cortisol elevation effects — chronic high-dose GHRP-2 is not well-characterized for HPA-axis sequelae (suppression of endogenous cortisol rhythm, etc.); theoretical risk poorly mapped.
• Hyperprolactinemia consequences — at chronic high dose, sustained prolactin elevation could plausibly affect HPG axis (prolactin suppresses GnRH/LH) — relevant for HPG-axis-conscious users. Magnitude likely modest at standard 100-200 mcg dosing but compounds with other prolactin-elevating compounds (e.g., antipsychotics).
• Insulin resistance / impaired glucose tolerance — most plausible with chronic high-dose multi-year use. Pulsatile dosing limits magnitude but cortisol spillover is additive.
• Sleep apnea exacerbation — GH soft-tissue effects; relevant in pre-existing sleep-disordered breathing.
• Theoretical IGF-1 / cancer-promotion concern — same as the broader GH-axis class; pulsatile dosing produces lower chronic IGF-1 elevation than MK-677 or recombinant GH but absent long-term human data, this remains a watch item.
• Acromegaly-spectrum effects at chronic supraphysiologic dosing — not clinically observed at therapeutic doses but the ceiling concern of any GH-axis intervention.

Specific watch periods:

• First 2-4 weeks: Headache, water retention, cortisol-feel, hunger surge — usually self-resolve or stabilize. Reduce dose if persistent.
• Week 8-12 bloodwork: Fasting glucose, fasting insulin, HbA1c, IGF-1, IGFBP-3, lipid panel, and AM cortisol + prolactin + ACTH (the GHRP-2-specific watch markers — confirm whether the spillover is producing measurable axis disruption).
• Month 6+: Reassess whether continued use vs. switch to ipamorelin is justified.