Complete List of Research Peptides and Their Mechanisms

Research peptides don’t map neatly to a single category. The word “peptide” just means a short chain of amino acids, which tells you almost nothing about mechanism, receptor, or research application. A complete list of research peptides and their mechanisms needs to organize them by what they actually target, not by alphabetical order or molecular weight.

This guide covers the major research peptides organized by mechanism class, with their primary receptor targets and research applications. It’s not exhaustive of every compound that exists, but it covers the established research compounds with documented preclinical evidence. Where Spartan carries the compound, we’ve linked to the product page. For full mechanistic deep dives on any compound, the research library entries go considerably deeper than a list format allows.

GH Axis Peptides: GHRH Analogs and GHRPs

This is the most studied peptide class in the research literature, covering compounds that stimulate endogenous growth hormone release through two complementary pathways.

GHRH Analogs (GHRH receptor agonists):

• CJC-1295 (Modified GRF 1-29): GHRH receptor agonist, stimulates pulsatile GH release when combined with a GHRP. Half-life approximately 30 minutes. Often combined with Ipamorelin for synergistic GH pulse amplification.
• CJC-1295 with DAC: Same core sequence as Mod GRF 1-29 plus albumin-binding Drug Affinity Complex. Half-life 6-8 days due to albumin conjugation. Produces sustained GH/IGF-1 elevation in research models.
• Tesamorelin: Stabilized GHRH(1-44) analog. The most clinically studied GHRH analog, approved for HIV-associated lipodystrophy research. Stimulates pulsatile GH through pituitary GHRH receptor.

GHRPs (GHS-R1a agonists):

• Ipamorelin: Selective GHS-R1a agonist with minimal appetite stimulation or cortisol elevation at research doses. The “cleanest” GHRP for studies where metabolic confounds need to be minimized.
• GHRP-2: GHS-R1a agonist, more potent GH releaser than Ipamorelin. Some cortisol and prolactin elevation documented in research models. Commonly combined with GHRH analogs.
• GHRP-6: The first GHRP studied systematically. Strong GH release with significant appetite stimulation via ghrelin receptor activation. Useful for research designs studying appetite-GH interactions.
• Hexarelin: Most potent GHRP for GH release amplitude. Also binds CD36 (scavenger receptor) in cardiac tissue, producing GH-independent cardioprotective effects in ischemia-reperfusion models. Shows faster tachyphylaxis than GHRP-2 with continuous dosing.

Tissue Repair and Regeneration Peptides

These compounds work through angiogenic, cytoprotective, and cytoskeletal mechanisms to support tissue repair in preclinical models. Distinct from GH axis compounds in mechanism.

• BPC-157: 15-amino acid synthetic peptide derived from human gastric juice. Upregulates VEGF expression and promotes angiogenesis in damaged tissue. Documented in preclinical models for tendon repair, GI cytoprotection (Sikiric group, Zagreb), and gut-brain axis interactions. Resistant to GI hydrolysis, enabling oral administration in animal models.
• TB-500: Synthetic thymosin beta-4 fragment (Ac-SDKP derived). Promotes G-actin sequestration and cell migration, enabling wound healing and tissue repair. Documented effects on angiogenesis, satellite cell activation, and cardiac repair in preclinical models. The Wolverine BPC-157/TB-500 blend combines both repair mechanisms.
• GHK-Cu: Copper-binding tripeptide Gly-His-Lys, endogenous in human plasma. Modulates copper transport, upregulates antioxidant enzymes (SOD, catalase), promotes collagen synthesis, and influences gene expression programs relevant to tissue remodeling. Studied in wound healing, skin models, hair follicle biology, and anti-aging applications.
• IGF-1 LR3: IGFBP-resistant IGF-1 analog with 20-30 hour half-life. Activates IGF1R-PI3K/Akt and MAPK/ERK pathways. Used in muscle satellite cell research, bone biology, and neuroprotection models. Standard tool for sustained IGF-1 receptor activation in cell culture and in vivo protocols.

Cognitive and Neuropeptides

These compounds target central nervous system receptors and neurotrophic pathways. Research applications include memory, learning, neuroprotection, sleep architecture, and mood regulation.

• Semax: ACTH 4-10 derived heptapeptide. Acts on melanocortin receptors (MC4R) to upregulate BDNF and TrkB via CREB transcription factor. Documented cognitive improvements in spatial memory tests and neuroprotection in ischemia models. Developed in Russia, studied since the 1980s.
• Selank: Tuftsin analog with GABA and serotonin modulating activity. Anxiolytic effects in rodent models (elevated plus maze, open field tests). Developed in parallel with Semax at the same Russian research institute. Often combined with Semax in research designs.
• DSIP (Delta Sleep Inducing Peptide): Nonapeptide isolated from rabbit brain (Monnier group, 1977). Promotes slow-wave sleep (EEG delta waves) in animal models. Also studied for HPA axis modulation and cortisol rhythm effects. Endogenous concentrations show circadian fluctuation.
• Epithalon: Tetrapeptide Ala-Glu-Asp-Gly derived from pineal gland extract (Khavinson group). Activates telomerase in cell culture models, extends lifespan in some rodent studies, and modulates circadian rhythm gene expression. One of the more extensively studied anti-aging peptides.
• Pinealon: Tripeptide Glu-Asp-Arg from the pineal gland (also Khavinson group research). Neuroprotective effects in rodent models of brain ischemia and oxidative stress. Some data on age-related cognitive decline models in rats.
• NAD+ precursor compounds: While not peptides strictly, NAD+ and related compounds are studied alongside neuropeptides for their roles in cellular energy metabolism, DNA repair (PARP activity), and sirtuin activation relevant to neurodegenerative disease models.

Metabolic Peptides

Compounds studied for effects on body composition, lipid metabolism, and glucose regulation in preclinical models.

• AOD-9604: hGH Fragment 176-191. A C-terminal fragment of growth hormone that retains the lipolytic activity of full-length GH without binding GH receptor for anabolic signaling. Stimulates fat cell breakdown (lipolysis) and inhibits lipogenesis in adipose tissue in animal models. Studied in obesity research without the IGF-1-elevating effects of full GH.
• GLP-1 Sema (GLP-1 GLP-1(Sema) class): Research-use only designation for GLP-1 receptor agonist compounds. Activate GLP-1R in pancreatic beta cells (insulin secretion), brain (appetite regulation), and GI tract (gastric emptying delay). Extensively studied in Type 2 diabetes and obesity preclinical models. Available through Spartan’s research catalog.
• GLP-2 Tirz (GLP-2 GLP-2(Tirz) class): Dual GIP/GLP-1 receptor agonist peptide class. GIP activation provides additive glucose-lowering and metabolic effects alongside GLP-1R agonism. Studied in metabolic syndrome and body composition research models. See Spartan’s GLP-2 research compound.
• GLP-3 Reta (GLP-3 GLP-3(Reta) class): Triple agonist at GLP-1R, GIP receptor, and glucagon receptor. The glucagon receptor component adds direct hepatic fat-burning effects. The most aggressive metabolic axis stimulation of the GLP compound classes. Available for research use.
• MOTS-C: Mitochondria-derived peptide (encoded by the mitochondrial 12S rRNA gene). Studied for effects on insulin sensitivity, exercise performance, and metabolic flexibility in rodent models. Activates AMPK signaling in skeletal muscle and adipose tissue.

Immune and Anti-Aging Peptides

Compounds with primary research applications in immune regulation, cellular aging, and longevity models.

• Thymosin Alpha-1: 28-amino acid peptide originally isolated from thymic tissue (Goldstein group). Activates toll-like receptors (TLR2, TLR9) and modulates dendritic cell and T-cell responses. Studied extensively in immune activation models and as an adjuvant in vaccine research protocols.
• Epithalon: (also listed under cognitive/neuropeptides above) Anti-aging peptide with documented telomerase activation in cell culture and lifespan effects in rodent studies. Modulates expression of clock genes and circadian rhythm regulators.
• Follistatin 344: Myostatin inhibitor. Also inhibits activin and other TGF-beta family members. Used in muscle wasting disease models and muscle biology research examining myostatin pathway regulation.

Reproductive and Sexual Health Peptides

Research compounds studied in reproductive biology and sexual function preclinical models.

• PT-141 (Bremelanotide): Cyclic heptapeptide, melanocortin receptor agonist (MC3R and MC4R). Studied for effects on sexual arousal and libido in rodent models. Unlike PDE5 inhibitors, acts centrally rather than through vascular mechanisms. Derived from Melanotan II with modifications for improved tolerability in research models.
• Kisspeptin: Hypothalamic neuropeptide that activates GnRH (gonadotropin-releasing hormone) neurons via KISS1R (GPR54) receptor. Drives pulsatile LH release and downstream testosterone/estrogen production. Key regulator of puberty onset and reproductive cyclicity. Studied in HPG axis regulation and reproductive endocrinology models.

How to Use This List

The best entry point for research peptide selection is identifying the biological mechanism relevant to your research question, then finding compounds that target that mechanism specifically. Organizing by mechanism rather than by name avoids the common problem of selecting peptides based on marketing categories (“recovery”, “fat loss”, “cognitive”) that obscure the actual receptor biology.

The full Spartan research catalog with individual product pages and purity documentation covers all the compounds mentioned here. The research library provides mechanism-focused deep dives with PubMed citations for each compound.

For researchers designing combination protocols, understanding which pathways are independent (e.g., GHS-R1a agonism and GHRH receptor agonism both releasing GH through different receptors) versus redundant helps optimize experimental design without wasting compounds on mechanistic overlap.

Related Research Reading

• Hexarelin: Growth Hormone Secretagogue Mechanisms
• DSIP (Delta Sleep Inducing Peptide): Sleep Architecture Research
• BPC-157 for Gut Health: Gastric Cytoprotection Research
• Ipamorelin Research Guide: Selective GH Secretagogue
• Epithalon: Telomerase Activation and Anti-Aging Research Guide

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Research Disclaimer: The information presented in this article is intended for educational and research purposes only. The compounds discussed are research chemicals and are not approved by the FDA for human use, consumption, or therapeutic application. All research must be conducted in accordance with applicable laws and regulations. Spartan Peptides supplies research-grade compounds exclusively for in vitro and laboratory research use.