For research use only · Not for human consumption
This material is reference information for laboratory study of research peptides. It is not medical advice and it is not instructions for human use, self-administration, or therapeutic application. Capital Peptides supplies research chemicals for in-vitro and animal-model study only. Discuss any health-related questions with a licensed medical practitioner.
Side effect profiles differ significantly between peptide classes. Find your primary compound below.
1. GH secretagogues (CJC-1295, Ipamorelin, GHRP-2/6, Sermorelin)
| Day | What's normal | Notes |
|---|---|---|
| 1–2 | Mild fatigue within 30–60 minutes of injection. Some hunger increase (especially GHRP-2/6). Tingling or flushing at injection site. | These are expected GH release signs. Fatigue is from GH pulse effect. |
| 2–4 | Increased slow-wave sleep in EEG/actigraphy data. Possible transient headache. Mild oedema onset (peripheral, hands/feet). | Improved sleep architecture is a frequently reported early GH-axis effect in preclinical and observational research. Headache typically self-resolves. |
| 4–7 | Water retention may peak — some notice ring tightness or slight face puffiness. Hunger (especially GHRP) becomes more manageable. | Water retention typically resolves in week 2–3 as the body adapts. |
| After week 1 | Side effects generally diminish as adaptation occurs. Positive effects (sleep, recovery) continue building. | The first week is typically the most side-effect-heavy. |
💡 Tip: GHRP-2 and GHRP-6 significantly increase ghrelin (hunger hormone) — this is expected and normal. Ipamorelin has a much weaker hunger effect and is preferred by those who find GHRP hunger disruptive.
2. Healing peptides (BPC-157, TB-500)
| Day | What's normal | Notes |
|---|---|---|
| 1–3 | Mild injection-site reactions (redness, small bump, temporary tenderness). Some researchers notice increased warmth at injury site. | Local injection-site reaction is normal. Warmth at target site may reflect increased blood flow. |
| 3–5 | Energy levels may shift — some notice mild fatigue, others increased energy. Sleep quality often improves. | Individual variation is high. Both responses are reported. |
| 5–7 | May begin noticing subtle pain reduction at injury site. Not dramatic at this stage — anti-inflammatory effects build gradually. | Don't expect dramatic pain relief in week 1. The compounding effect comes in weeks 2–4. |
BPC-157 and TB-500 have very low side-effect profiles. First-week effects are typically minimal beyond injection-site reactions.
3. GLP-1 agonists (semaglutide, tirzepatide, retatrutide)
| Day | What's normal | Notes |
|---|---|---|
| 1 | Appetite suppression begins, often noticeably within 24 hours. Possible mild nausea. | Start at the lowest dose. GLP-1 nausea is dose-dependent. |
| 2–4 | Nausea may peak — especially after eating. Possible constipation or loose stools. Fatigue in some users. | Eating smaller meals, slowly, reduces nausea significantly. Avoid fatty or spicy foods initially. |
| 4–7 | Nausea typically begins to reduce as GI tract adapts. Appetite suppression persists. Some notice heartburn. | Most people find week 2+ much easier than the first week. |
⚠️ Important: GLP-1 nausea in week 1 can be significant. This is a known, expected, and dose-dependent effect — not an allergic reaction. If nausea is severe enough to prevent eating, consider pausing and restarting at a lower dose.
4. Cognitive peptides (Semax, Selank, NA-Semax, PE-22-28)
| Day | What's normal | Notes |
|---|---|---|
| 1 | Semax: many researchers notice acute cognitive clarity, improved focus within hours of first dose. | Acute effect is a good sign the compound is active. |
| 1–3 | Selank: anxiolytic effect may begin — reduced background anxiety, calmer response to stressors. | Selank onset is typically gentle and builds over first week. |
| 2–5 | Mild stimulation (Semax) — may affect sleep if dosed too late in the day. Some notice increased dream vividness. | Dose Semax earlier in the day (morning / early afternoon) if sleep is disrupted. |
| After week 1 | Effects stabilise. Some researchers notice a plateau and cycle off for 1–2 weeks to maintain sensitivity. | Cycling cognitive peptides maintains responsiveness. |
5. Red flags — stop and seek medical attention
These symptoms at any point in week 1 (or beyond) are not normal and require stopping the protocol:
- Injection site with spreading redness, significant swelling, or pus (suggests contamination / infection)
- Chest pain, palpitations, or irregular heartbeat
- Shortness of breath disproportionate to activity
- Severe or sudden headache unlike previous headaches
- Visual disturbances — blurring, double vision, visual field changes
- Urticaria (hives), facial swelling, or throat tightness — allergic reaction
- Blood glucose significantly outside your normal range (relevant if you have diabetes or monitor glucose)
- New lump, growth, or swollen lymph node appearing during cycle
🚫 Warning: If you experience any of the above, stop the compound and see a doctor. Do not post on a forum and wait for answers — seek medical attention promptly.