Understanding units: mcg vs mg
Most peptides are dosed in micrograms (mcg), not milligrams (mg). There are 1,000 mcg in 1 mg. This distinction matters enormously when reconstituting lyophilised (freeze-dried) peptides. A common mistake is confusing the two, which can result in a dose 1,000 times too high or too low.
Reconstitution: the basics
Most peptides arrive as a white lyophilised powder. To use them, you reconstitute with bacteriostatic water (BW). A standard approach: add 1–2 ml of BW to a 5 mg vial. This gives you a concentration of 2.5–5 mg/ml. Use a sterile insulin syringe to draw your dose. Store reconstituted peptides refrigerated and use within 28–30 days.
Timing your injections
Timing depends on the peptide and your goals. Growth hormone secretagogues (like CJC-1295 + Ipamorelin) are most effective when injected before sleep or in a fasted state, as GH is naturally pulsed during these windows. BPC-157 is often injected near the injury site at any time of day. Semaglutide is a once-weekly injection on the same day each week.
Cycle structure: on/off periods
Most peptide protocols follow a cycle structure to prevent receptor desensitisation and maintain effectiveness. A common approach is 8–12 weeks on, followed by 4–8 weeks off. Some peptides (like Epithalon) are used in short, infrequent bursts — 10–20 days, 1–2 times per year. Always plan your off period before you start.
Key takeaways
- 1 mg = 1,000 mcg — never confuse the two when calculating doses
- Reconstitute with bacteriostatic water and store refrigerated
- Time injections to align with the peptide's mechanism (fasted, pre-sleep, etc.)
- Plan your off period before you start — cycle structure prevents desensitisation