Peptide Cheat Sheet

Understanding units#

Peptides are dosed in micrograms (mcg) or milligrams (mg). 1 mg = 1,000 mcg. Most healing peptides (BPC-157, TB-500) are dosed in mcg to low mg. GH secretagogues are typically dosed in mcg. GLP-1 agonists (Semaglutide, Tirzepatide) are dosed in mg. IU (International Units) are sometimes used for HGH but not for peptides — don't conflate the two. The Reconstitution Calculator in the app converts your vial concentration to the exact volume per dose.

Use the Staqk dose calculator to convert mcg to syringe units based on your reconstitution ratio.

Injection routes#

Subcutaneous (SubQ): inject into the fat layer just under the skin, 45° angle, short needle (5/16" or 8mm). Most common for peptides. Intramuscular (IM): inject into muscle at 90°, longer needle. Less common but used for some compounds (e.g. TB-500 for localized effect). Intranasal: a few peptides (PT-141, some oxytocin analogs) can be taken via nasal spray. Bioavailability is lower and more variable than SubQ.

Half-life reference#

Short half-life (2–6 hours) — dose 1–2x daily: BPC-157, GHRP-2, GHRP-6, Ipamorelin, CJC-1295 (without DAC), PT-141. Medium half-life (1–3 days) — dose every 1–3 days: TB-500, CJC-1295 (with DAC), Hexarelin. Long half-life (days to 1 week) — dose weekly: Semaglutide (Ozempic), Tirzepatide (Mounjaro). Half-life determines dosing frequency — compounds with short half-lives need more frequent dosing to maintain steady tissue levels.

General dosing principles#

Start at 50% of the commonly referenced dose for the first week. If well tolerated, step up to the full dose. Splitting total daily dose across two injections is preferred for short half-life peptides. For GH secretagogues, the most studied timing is before sleep and/or first thing in the morning in a fasted state. More is not always better — many peptides show a plateau or even diminishing returns at high doses.

Meal timing and fasting#

GH secretagogues (CJC-1295, Ipamorelin, GHRP-6): best dosed fasted — elevated insulin blunts the GH pulse. Wait at least 2 hours after eating, or inject first thing in the morning. BPC-157 and TB-500: timing relative to meals is not critical. GLP-1 agonists: taken regardless of meal timing as they regulate appetite rather than pulse GH. PT-141: dosed 45–60 minutes before intended effect.