Most peptides fall into six groups, sorted by the job they are asked to do. The six are recovery and healing, sleep, weight management, anti-aging and skin, growth hormone release, and metabolism.
Sorting by what they are asked to do
Peptides are categorised by function, not by structure. Six groupings cover almost everything you will encounter.
1. Recovery and healing
BPC-157 and TB-500: the "Wolverine Stack". BPC-157 is a synthetic 15-amino-acid peptide derived from human gastric juice that works locally through angiogenesis and nitric oxide modulation. TB-500 is the acetylated seven-amino-acid fragment Ac-LKKTETQ, residues 17–23 of the 43-amino-acid thymosin beta-4. The actin-regulation and cell-migration mechanism usually quoted for it is thymosin beta-4's: FDA states that acetylation irreversibly alters charge, hydrophobicity and size, so the parent's results cannot be extrapolated to TB-500. The mechanism is inherited, not demonstrated.
Evidence position: BPC-157 has dozens of animal studies, and FDA's July 2026 review found five small human studies. TB-500's fragment has never been studied separately in humans. Behind the stack itself: one 16-patient retrospective report in people, and a 2026 rat study in which the pair did no better than either peptide alone.
2. Sleep
DSIP: Delta Sleep-Inducing Peptide, a naturally occurring 9-amino-acid neuropeptide first isolated in 1977. It targets sleep depth rather than sleep onset, which is the distinction that separates it from melatonin.
Adjacent: Epitalon for circadian rhythm through pineal melatonin support, GHRP-2 and GHRP-6 for the growth hormone pulse that deepens slow-wave sleep, and Selank for anxiety-driven insomnia.
3. Weight management
The fastest-growing class of peptide drugs. Semaglutide (Wegovy, Ozempic) is a single GLP-1 agonist producing around 15% body weight loss. Tirzepatide (Zepbound, Mounjaro) adds GIP for around 22.5%. Retatrutide adds glucagon on top of both for around 28% at 80 weeks in Phase 3, a conference presentation with no registry results posted.
Also here: AOD-9604, a growth hormone fragment with limited and mixed human data.
4. Anti-aging and skin
GHK-Cu is the anchor: a copper-binding tripeptide isolated in 1973, influencing over 4,000 genes.
Alongside it: Matrixyl 3000, a signal peptide that tells fibroblasts to make collagen, and Argireline, which targets expression lines by relaxing the muscles that create them. Different mechanisms, so they complement rather than compete.
5. Growth hormone secretagogues
Tesamorelin is the only FDA-approved peptide specifically for visceral fat reduction. CJC-1295 and sermorelin are other GHRH analogs. Ipamorelin, GHRP-2 and GHRP-6 work the other pathway, through the ghrelin receptor. MK-677 is the oral option, producing sustained rather than pulsatile elevation.
The pairing logic: a GHRH analog plus a ghrelin-receptor compound hits two separate receptors and produces a larger pulse than either alone. Two GHRH analogs together, or two GHRPs together, is duplication.
6. Metabolism and mitochondria
MOTS-C, a 16-amino-acid peptide encoded in mitochondrial DNA, called an "exercise mimetic" because it activates AMPK, the same metabolic switch exercise flips. Human muscle levels spike up to 12-fold during exercise.
Why categories matter for stacking
This is not filing for its own sake. The Playbook's second stacking principle is non-overlapping mechanisms only. Recovery plus sleep is two different systems, which is defensible. Two growth-promoting peptides is one system twice, which is amplified risk without amplified benefit.
Knowing the category tells you whether a proposed combination is complementary or redundant before you spend a dollar on it.