The Complete Guide to Types of Peptides: Categories, Examples, and What Each One Does
If you are new to peptides, the sheer number of compounds you will see referenced online can be overwhelming. BPC-157. CJC-1295. Ipamorelin. Semax. Selank. Epitalon. GHK-Cu. TB-500. Tesamorelin. PT-141. MOTS-c. FOXO4-DRI. Every one of these names represents a different peptide, targeting a different system, with its own dosing, evidence base, and user experience.
The good news is that almost every therapeutic peptide you will encounter falls into one of roughly eight functional categories. Once you understand what each category does and what the “flagship” peptides in each are used for, the landscape becomes dramatically less confusing.
This guide is part two of our peptide series. If you haven’t already, start with our foundational explainer — what peptides are and how they work.
How We Categorize Peptides
There is no single “official” peptide taxonomy. We use the functional grouping below — the one working clinicians and experienced biohackers tend to use:
- Healing and tissue-repair peptides
- Growth hormone secretagogues (GH-releasing peptides)
- Metabolic and weight-loss peptides
- Longevity and anti-aging peptides
- Cognitive and mood peptides (nootropic peptides)
- Cosmetic and skin peptides
- Sexual health peptides
- Immune-modulating peptides
1. Healing and Tissue-Repair Peptides
Purpose: accelerate recovery from injury; support gut, tendon, ligament, and soft-tissue healing; reduce inflammation; promote angiogenesis.
Who uses them: athletes recovering from injuries, people with chronic tendinopathy or joint issues, anyone with gut issues, post-surgical patients under medical supervision.
BPC-157
Probably the single most famous peptide in the biohacking world. BPC-157 (“Body Protective Compound”) is a synthetic sequence derived from a protective peptide found in gastric juice. It is most associated with gut healing but animal and anecdotal evidence point to benefits across tendon, ligament, muscle, and brain tissue. Typically dosed at 250–500 mcg once or twice daily via subcutaneous injection.
TB-500 (Thymosin Beta-4 Fragment)
A synthetic fragment of thymosin beta-4, involved in actin regulation and tissue repair. Users report particular benefit for muscle recovery, tendon repair, and cardiac tissue. Often stacked with BPC-157 as “the healing stack.” Typically dosed 2–2.5 mg twice weekly.
GHK-Cu (as Injectable), KPV, and Pentadeca Arginate (PDA)
GHK-Cu used systemically has impressive tissue-repair and anti-fibrotic properties. KPV is a short tripeptide with strong anti-inflammatory activity, particularly in the gut. PDA is a newer peptide positioned as an evolution of BPC-157.
2. Growth Hormone Secretagogues (GH-Releasing Peptides)
Purpose: prompt your pituitary to release your own growth hormone in a natural, pulsatile pattern.
Who uses them: people over 30 looking to preserve lean mass and recovery, those with poor sleep quality, anyone optimizing body composition or training recovery.
GHRH analogues
- Sermorelin — a 29-amino-acid fragment of GHRH, short-acting.
- CJC-1295 (without DAC) — similar to sermorelin but modified for slightly longer activity.
- CJC-1295 with DAC — attached to a drug affinity complex that extends half-life to 6–8 days.
- Tesamorelin — an FDA-approved GHRH analogue for HIV-associated lipodystrophy, also used off-label for visceral fat reduction.
GHRPs / ghrelin mimetics
- Ipamorelin — the cleanest GHRP. Minimal effect on cortisol and prolactin.
- GHRP-2, GHRP-6, Hexarelin — older, stronger GHRPs.
- MK-677 (Ibutamoren) — orally active, long-acting ghrelin mimetic.
The classic stack: CJC-1295 (no DAC) + Ipamorelin. Typical dosing is 100 mcg of each, 1–3 times daily, with at least one dose before bed.
3. Metabolic and Weight-Loss Peptides
Purpose: regulate appetite, improve insulin sensitivity, burn fat, and support metabolic flexibility.
GLP-1 Receptor Agonists
- Semaglutide (Ozempic, Wegovy, Rybelsus) — the peptide that reshaped the obesity conversation globally.
- Tirzepatide (Mounjaro, Zepbound) — dual GLP-1 and GIP agonist. Generally more potent than semaglutide.
- Liraglutide (Saxenda, Victoza) — older daily-injection GLP-1.
- Retatrutide — triple agonist in late-stage trials.
AOD-9604, Tesamorelin, 5-Amino-1MQ
AOD-9604 is a synthetic fragment of hGH (amino acids 176–191) specifically engineered for fat-loss effects. Tesamorelin is particularly effective at reducing visceral fat. 5-Amino-1MQ is technically a small molecule often grouped with metabolic peptides.
4. Longevity and Anti-Aging Peptides
Purpose: address hallmarks of aging — cellular senescence, telomere attrition, mitochondrial decline, stem cell exhaustion, and systemic inflammation.
- Epitalon (Epithalon) — a four-amino-acid peptide believed to activate telomerase. Multiple human studies suggest mortality reduction.
- Thymalin — a thymic peptide that restores aspects of immune function in the elderly. Often paired with Epitalon.
- FOXO4-DRI — a senolytic peptide that selectively triggers apoptosis in senescent cells.
- MOTS-c — a mitochondrial-derived peptide linked to metabolic health and longevity.
- Humanin — another mitochondrial-derived peptide with neuroprotective and metabolic effects.
- SS-31 (Elamipretide) — a mitochondria-targeted peptide studied in age-related dysfunction.
See our dedicated article on peptides and longevity for full coverage.
5. Cognitive and Mood Peptides (Nootropic Peptides)
Purpose: support memory, focus, anxiety regulation, neuroprotection, and neural repair.
- Semax — a Russian-developed heptapeptide. Reported effects: increased focus, motivation, and verbal fluency. Intranasal.
- Selank — for anxiety, sleep, and mood stabilization without sedation. Intranasal.
- Cerebrolysin — a mixture of peptides used for stroke, TBI, Alzheimer’s, and vascular dementia.
- Dihexa — an oral peptide with remarkable synaptogenic potency in animal studies.
- P21, Noopept — research-stage and small-molecule dipeptide respectively.
6. Cosmetic and Skin Peptides
Purpose: improve skin firmness, reduce wrinkles, support collagen synthesis, promote hair growth.
- GHK-Cu (Copper Peptide) — the classic. Strong evidence for stimulating collagen and elastin synthesis.
- Matrixyl (Palmitoyl Pentapeptide-4) — topical peptide in many commercial skincare products.
- Argireline (Acetyl Hexapeptide-8) — a “Botox-like” topical peptide.
- Thymosin Beta-4 (Topical) — used for hair regrowth protocols.
7. Sexual Health Peptides
- PT-141 (Bremelanotide) — FDA-approved for hypoactive sexual desire disorder in women. Acts centrally via the melanocortin system.
- Kisspeptin-10 — upstream regulator of the reproductive axis.
- Melanotan II — related to PT-141 but primarily used for tanning; not recommended for that use.
8. Immune-Modulating Peptides
- Thymosin Alpha-1 (TA-1) — long clinical use in immunocompromised patients, hepatitis B/C, some cancer adjunctive protocols, and long COVID.
- Thymulin — zinc-dependent thymic peptide.
- LL-37 — human antimicrobial peptide with broad antibacterial, antiviral, and anti-biofilm properties.
- KPV — alpha-MSH fragment with immune-modulating effects.
A Framework for Choosing Which Peptide Category Fits Your Goal
- “I want to recover faster from training or an injury.” → Healing peptides (BPC-157, TB-500, KPV).
- “I want better body composition, deeper sleep, and faster recovery.” → GH-releasing peptides (CJC-1295 + Ipamorelin).
- “I want to lose fat.” → Metabolic peptides (GLP-1 agonists, AOD-9604, Tesamorelin).
- “I want to extend healthspan.” → Longevity peptides (Epitalon, Thymalin, MOTS-c).
- “I want to think more clearly or manage anxiety.” → Cognitive peptides (Semax, Selank, Cerebrolysin).
- “I want better skin and hair.” → Cosmetic peptides (GHK-Cu topical + systemic).
- “I want to support libido.” → Sexual health peptides (PT-141).
- “I want immune support.” → Thymosin alpha-1.
Peptide Stacks: How Categories Combine
- Recovery stack: BPC-157 + TB-500.
- GH stack: CJC-1295 (no DAC) + Ipamorelin.
- Anti-aging stack: GH stack + Epitalon (cycled) + GHK-Cu topical.
- Longevity protocol: Epitalon + Thymalin + MOTS-c, cycled through the year.
- Performance + recovery: GH stack + BPC-157 during training cycles.
Legal Status by Category
FDA-approved, prescription peptides: semaglutide, tirzepatide, liraglutide, tesamorelin, sermorelin (via compounding), PT-141, thymosin alpha-1 (status varies).
Research-use-only in the US: BPC-157, TB-500, CJC-1295, Ipamorelin, GHK-Cu (injectable), Epitalon, MOTS-c, FOXO4-DRI, Semax, Selank, and most others.
Frequently Asked Questions
What are the most popular peptides?
BPC-157 and TB-500 in the healing category; CJC-1295 + Ipamorelin in the GH category; semaglutide and tirzepatide in the metabolic category; Epitalon in longevity; GHK-Cu in cosmetics.
Which peptides are safest?
GHK-Cu (especially topical), Ipamorelin, BPC-157, and the thymic peptides have among the best safety records in typical use. Safety always depends on source quality and dose.
Can I stack peptides from different categories?
Yes, and most serious protocols do. Stacking is typically additive rather than synergistic.
Are all peptides injectable?
Most are, but not all. Intranasal, topical, oral, and sublingual options exist for a subset of peptides.
How many peptides exist?
Thousands of biologically active peptide sequences have been identified. The number used therapeutically is in the low hundreds.
Do I need a prescription for every peptide?
In the US, FDA-approved peptides require a prescription. Research-use-only peptides do not, but using them therapeutically is a legal gray area best navigated with a clinician.
The Bottom Line
Once you map peptides by function rather than by name, the landscape gets much more manageable. Eight categories cover effectively everything you will encounter. Most people start in one or two categories, then layer in others once they have a feel for how their body responds.
Next in the series: the biggest myths about peptides, where we separate hype from evidence.