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Evidence-led overview

Types of peptides &
what the research shows

Peptides are short chains of amino acids that act as signalling molecules in the body. Below is a plain-English overview of the main categories researchers study, how each works, and the headline results that laboratory and clinical studies have reported so far.

6

Research areas

19

Compounds

≥99%

Purity

HPLC · LC-MS

Verified

For research use only. The figures and findings below are educational and summarise published laboratory, animal and clinical research. They describe what studies have observed — they are not medical advice and are not a claim about the safety or effectiveness of any product for human or veterinary use. Defined Labs products are not for human consumption.

01

GLP-1 · GIP · Glucagon

Metabolic & body-composition peptides

This is the most clinically advanced area of peptide research. These compounds mimic the body's own incretin and growth-hormone-releasing hormones to influence glucose handling, appetite signalling and fat metabolism.

Retatrutide

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Phase 2 trials

Triple GLP-1 / GIP / glucagon receptor agonist — a leading metabolic research compound

A single molecule that acts on three receptors at once — GLP-1, GIP and glucagon. This triple-agonist profile has made it one of the most closely followed investigational compounds in metabolic research, and it has been the subject of clinical research programmes investigating metabolic endpoints. As an investigational compound, findings continue to develop within the conditions of each study.

Tesamorelin

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FDA-approved

Stabilised GHRH analogue studied for visceral adipose-tissue endpoints

A stabilised analogue of growth-hormone-releasing hormone (GHRH) and one of the few peptides here with regulatory approval for a specific clinical indication. It has been studied in clinical research for visceral adipose-tissue, liver-fat and cognition endpoints. Findings should be interpreted within the conditions of each study.

02

Healing · Recovery

Tissue repair & recovery peptides

Studied largely in preclinical (cell and animal) models, these peptides are investigated for their effects on angiogenesis — the growth of new blood vessels — and on the remodelling of connective tissue, gut lining, tendon and muscle.

BPC-157

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Preclinical (animal)

Studied for tendon, ligament & gut-tissue repair endpoints in animal models

A 15-amino-acid sequence derived from a protein in gastric juice. It has been studied in numerous animal models for tissue-repair, angiogenesis and tissue-protection endpoints. Robust human clinical data does not yet exist, so these findings remain preclinical.

TB-500

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Preclinical / early trials

Studied for wound-closure & cell-migration endpoints in animal models

A synthetic fragment of Thymosin Beta-4, a natural repair protein. Preclinical studies have examined wound-closure, cell-migration and tissue-remodelling endpoints. The parent protein has been investigated in early clinical research for wound and corneal-healing endpoints.

03

GH Secretagogues

Growth-hormone pathway peptides

Rather than supplying growth hormone directly, these peptides prompt the pituitary gland to release more of the body's own — aiming for a more physiological, pulsatile pattern of secretion.

Ipamorelin

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Preclinical

Selective GH pulse with little to no rise in cortisol or prolactin

A selective ghrelin-receptor agonist that stimulates a clean pulse of growth hormone with minimal effect on cortisol or prolactin in research models — which is why it's a common reference compound in GH-axis studies.

CJC-1295 / Ipamorelin

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Early-phase clinical

Long-acting GHRH analogue studied for GH-axis & IGF-1 endpoints

Combines a long-acting GHRH analogue with Ipamorelin. It is studied for GH-axis stimulation, with research examining growth-hormone and IGF-1 endpoints across two complementary pathways. Findings are drawn from the specific models of each study.

04

Neuropeptides

Cognitive & neurological peptides

Short peptides that cross into the nervous system and modulate neurotrophic factors — the proteins that support neuron growth, survival and plasticity. Several originated in Russian clinical research.

Semax

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Approved (Russia)

Studied for BDNF and neuroprotective endpoints in ischaemia models

Derived from a fragment of ACTH. Research has examined its effects on BDNF (a key neurotrophic factor) and neuroprotective endpoints in models of ischaemia and oxidative stress. Findings are drawn from the specific research models of each study.

Selank

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Approved (Russia)

Studied for anxiety-related and immune-signalling endpoints in behavioural models

An analogue of the immunopeptide tuftsin. It is studied in neuroscience research for anxiety-related behavioural endpoints via the GABA system, alongside immune-modulating signalling. Findings are drawn from the specific models of each study.

05

Longevity · Mitochondria

Cellular health & longevity compounds

An emerging field exploring telomere biology, mitochondrial function and the metabolic pathways linked to ageing. Findings here range from animal studies to active clinical research programmes.

Epitalon

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Animal studies

Tetrapeptide studied for telomerase-activity & telomere-length endpoints

A tetrapeptide studied for its effect on telomerase activity and telomere length. Long-running rodent studies, particularly from Russian gerontology research, have examined effects on circadian-regulation and ageing-related endpoints.

MOTS-c

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Preclinical

Mitochondrial-derived peptide studied for insulin-signalling & metabolic endpoints

A peptide encoded within mitochondrial DNA that acts as a metabolic regulator. Preclinical work has examined its role in insulin-signalling, metabolic-adaptation and exercise-physiology endpoints in animal models.

SS-31

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Clinical research

Mitochondria-targeting peptide studied for cellular bioenergetic endpoints

Also known as elamipretide, this mitochondria-targeting peptide has been the subject of clinical research programmes examining cellular energy-production and oxidative-stress endpoints. Findings continue to develop within the conditions of each study.

NAD+

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Active research

Central to energy metabolism & DNA repair; levels fall markedly with age

An essential coenzyme involved in hundreds of metabolic reactions and in DNA repair. Because NAD+ levels decline substantially with age, it and its precursors are a major focus of longevity and metabolic research.

06

Skin · Collagen

Cosmetic & regenerative peptides

Peptides studied for their effects on skin, hair and collagen biology — some of the most extensively documented in cosmetic and dermatological research.

GHK-Cu

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Cosmetic / clinical studies

Studied for collagen-synthesis and skin-remodelling endpoints

A copper-binding tripeptide found naturally in plasma. It is one of the best-studied peptides in skin science, with research examining collagen and elastin synthesis, skin-remodelling, wound-healing biology and antioxidant gene-expression endpoints. Findings are drawn from the specific models of each study.

GLOW (GHK-Cu · BPC-157 · TB-500)

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Blend

Combines the cosmetic & repair peptides above for complementary research

A pre-combined blend pairing the cosmetic and repair peptides described above, researched for potential complementary effects on tissue and skin remodelling.

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Every compound is supplied at ≥99% purity with HPLC and LC-MS testing, and a Certificate of Analysis available on request.

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Products are supplied strictly for in vitro laboratory and scientific research. They are not medicines, supplements, foods or cosmetics, and are not intended for human or veterinary use, consumption, or any clinical or diagnostic purpose.

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