Peptide research has moved from a niche corner of biochemistry into one of the most active areas of metabolic, regenerative, and longevity science. Researchers studying everything from adipose signaling to dermal collagen biology now routinely reach for synthetic peptides as their primary investigative tool — small, receptor-selective molecules that isolate a single pathway far more cleanly than a full protein or a broad-spectrum drug.
This guide organizes the most actively studied research peptides into four categories — metabolic, growth-hormone axis, recovery and tissue repair, and longevity — so researchers can quickly find the compounds relevant to their protocol, along with the documented multi-peptide stacks built around them.
Metabolic and Weight-Related Research
Metabolic peptide research is currently the most active and best-funded area in the field, driven by the clinical prominence of GLP-1 receptor agonists as a drug class. That attention has pulled a wider ecosystem of related mechanisms into focus.
- Semaglutide — a GLP-1 receptor agonist studied for its effects on gastric emptying, appetite signaling, and insulin sensitivity in preclinical models.
- Tirzepatide — a dual GLP-1/GIP receptor agonist ("twincretin"), studied for additive effects on fat-storage regulation beyond single-receptor agonism. See our Tirzepatide mechanism overview.
- Retatrutide — a triple GLP-1/GIP/glucagon agonist; the added glucagon-receptor activity is of research interest for hepatic fat-oxidation pathways neither dual agonist engages. See Retatrutide vs. Tirzepatide.
- Cagrilintide — a long-acting amylin analog working through CALCR/RAMP receptor pathways rather than GLP-1 receptors, of interest for combination-mechanism research alongside incretin agonists.
- AOD-9604 — a modified hGH fragment (176–191) studied for lipolytic activity via beta-3 adrenergic signaling, isolated from hGH's anabolic/mitogenic effects.
Growth-Hormone Axis and Recovery-Adjacent Research
GH-secretagogue research typically pairs a GHRH analogue with a ghrelin-receptor agonist to drive GH pulse amplitude through two independent mechanisms.
- CJC-1295 and Ipamorelin — see our CJC-1295 vs. Ipamorelin breakdown and the paired CJC-1295 + Ipamorelin blend.
- Sermorelin and Hexarelin — additional GHRH-analogue and ghrelin-mimetic compounds used in comparative secretagogue research.
- Tesamorelin — a stabilized GHRH analogue studied specifically in visceral-adiposity research models.
- IGF-1 LR3 — a long-acting IGF-1 analogue used downstream of GH-axis research to study anabolic signaling directly.
Recovery and Tissue-Repair Research
- BPC-157 — among the most widely studied compounds in gastrointestinal and musculoskeletal tissue-repair models. See BPC-157 in tissue-repair research.
- TB-500 — a Thymosin Beta-4 fragment studied for angiogenesis and cell-migration signaling; frequently paired with BPC-157. See BPC-157 vs. TB-500 and the Wolverine Stack.
- KPV and GHK-Cu + KPV — studied for anti-inflammatory signaling research alongside tissue-repair protocols.
Longevity and Cellular Research
- GHK-Cu — a copper-binding peptide studied for collagen synthesis and dermal tissue-remodeling research.
- NAD+ — studied in cellular-metabolism and mitochondrial-function research models.
- MOTS-c — a mitochondrial-derived peptide studied in metabolic and cellular-stress signaling research.
- Semax and Selank — nootropic-adjacent peptides studied in neurotrophic and stress-response research models.
Documented Research Stacks
Several multi-peptide combinations recur often enough in the literature that they're worth sourcing as pre-paired stacks rather than combining separately purchased vials:
- Wolverine Stack (BPC-157 + TB-500) — joint musculoskeletal and angiogenesis research.
- Glow Stack (GHK-Cu + BPC-157 + TB-500) — combination dermal and tissue-repair research.
- KLOW Stack — a four-compound combination protocol; see the full KLOW Stack overview.
- CJC-1295 + Ipamorelin Blend — paired GH-secretagogue research, covered above.
Sourcing Considerations
Whichever compounds a protocol calls for, the same sourcing checklist applies across categories: batch-specific Certificates of Analysis, independently verified HPLC purity, confirmed molecular identity via mass spectrometry, and research-use-only labeling without human-use marketing language. See our guide to third-party testing for what to check before ordering from any supplier.