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Understand peptides, minus the hype.

Plain-language, evidence-aware summaries of the peptides people are researching - the good, the bad, and what the science actually says.

Browse by category

Grouped the way researchers actually think about them.

Metabolic & Weight

GLP-1s, fat-loss and metabolic compounds - the most-searched category, home to the FDA-approved blockbusters.

16 compounds

Healing, Recovery & Immune

Tissue-repair, gut, skin and immune peptides like BPC-157, TB-500, GHK-Cu and the thymosins.

12 compounds

Growth Hormone & Muscle

Growth-hormone secretagogues and muscle/IGF compounds - from CJC-1295 and ipamorelin to IGF-1 and follistatin.

12 compounds

Cognitive & Nootropic

Focus, memory, mood and sleep peptides - Semax, Selank, Dihexa, Cerebrolysin and more.

8 compounds

Longevity & Cellular

Anti-aging and cellular-health compounds - Epithalon, NAD+, MOTS-c, SS-31 and senolytics.

6 compounds

Hormones & Reproductive

Fertility and hormone-axis peptides - HCG, HMG, gonadorelin, kisspeptin and GnRH agonists.

6 compounds

Sexual, Skin & Aesthetic

Libido, tanning and cosmetic peptides - PT-141, melanotan and topical skin peptides.

5 compounds

Most-searched compounds

Where most people start.

GLP-1 receptor agonist

Semaglutide

FDA-approved weekly injectable / daily oral for diabetes and weight management (Novo Nordisk).

FDA-approved

Dual GIP / GLP-1 agonist

Tirzepatide

FDA-approved weekly injectable for diabetes and obesity (Eli Lilly).

FDA-approved

GLP-1 / GIP / glucagon triple agonist

Retatrutide

Investigational once-weekly injectable for obesity/metabolic disease (Eli Lilly, LY3437943).

Investigational

Synthetic pentadecapeptide

BPC-157

Lab-made 15-amino-acid peptide studied mainly in animals for healing tendon, muscle, gut and other tissue.

Research use only

Synthetic thymosin beta-4 fragment

TB-500

Synthetic ~7-amino-acid fragment reproducing the actin-binding region of thymosin beta-4; marketed for tissue repair. (Not full-length TB4.)

Research use only

Copper-binding tripeptide

GHK-Cu (Copper Peptide)

Naturally occurring copper-carrying peptide found in human plasma; widely used in skincare for anti-aging and repair.

Cosmetic use

GH secretagogue / ghrelin mimetic

Ipamorelin

A selective synthetic pentapeptide that stimulates the body's own GH release via the ghrelin receptor.

Research use only

Mitochondrial-derived peptide

MOTS-c

A 16-amino-acid peptide encoded in mitochondrial DNA that acts as a metabolic signaling molecule.

Research use only

Coenzyme / metabolic cofactor

NAD+ (injectable)

Injectable nicotinamide adenine dinucleotide - an essential coenzyme for cellular energy and DNA repair - given IV or subcutaneously.

Research use only

Melanocortin receptor agonist

PT-141 (Bremelanotide)

A synthetic cyclic peptide that increases sexual desire/arousal by acting on the brain rather than blood flow.

FDA-approved
A note on safety and legality. pep4U is an educational project. Many compounds listed are not approved by the FDA for human use and some are sold only “for research.” Regulations are actively changing in 2026. Nothing here is medical advice or an endorsement - please talk to a qualified clinician before making any health decision.

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