Peptides — dosing, safety & research

Plain-language guides to the compounds people actually ask about — each with typical dosing, an honest evidence rating, and cited sources.

Understanding peptides

Peptides are short chains of amino acids — the same building blocks that make up proteins, just smaller. In the body, many peptides act as signalling molecules: they bind receptors and tell cells what to do. That is why a single word — “peptides” — covers compounds with wildly different jobs.

Some, like BPC-157 and TB-500, are studied for tissue repair. The GLP-1 agonists — semaglutide, tirzepatide and retatrutide — regulate appetite and metabolism. Growth-hormone secretagogues such as CJC-1295 and ipamorelin raise GH and IGF-1, while copper peptides like GHK-Cu are used for skin and hair.

The evidence behind them varies enormously — from large randomized trials to animal-only data. That gap is exactly why we grade every compound, so nothing on this site reads as more certain than it really is.

How peptides are dosed

Most research peptides arrive as a lyophilized (freeze-dried) powder. You reconstitute it with bacteriostatic water, then draw a subcutaneous dose with a U-100 insulin syringe. How much water you add changes how many units each dose becomes — our free reconstitution calculator works out the exact units, and the half-life calculator shows how levels build across a cycle.

Safety, purity & sourcing

Because most peptides are sold “for research use only”, their purity and dosing are not guaranteed the way a prescription drug's are. Independent third-party testing (a Certificate of Analysis) matters, as does correct cold storage after reconstitution. Peptides can also interact with medications and conditions in ways that are poorly characterized — which is why every compound page here ends the same way: this is educational information, not a prescription, and you should talk to a licensed clinician before starting anything.

How we grade the evidence

Every compound page carries one of these badges. Check it before you trust a claim.

● Clinical trials

Backed by randomized human trials or established clinical use — e.g. the GLP-1 agonists semaglutide and tirzepatide.

◑ Limited human

Small or early-phase human studies. Promising signals, but far from settled — treat claims with caution.

◔ Preclinical

Animal or in-vitro data only, like most of BPC-157's evidence. Human effects are unproven.

Peptides by goal

Fat loss

GLP-1 and dual/triple agonists (semaglutide, tirzepatide, retatrutide) that regulate appetite and metabolism.

Recovery

Repair-focused peptides (BPC-157, TB-500) studied for tendon, ligament and soft-tissue healing.

GH axis

Growth-hormone secretagogues (CJC-1295, ipamorelin, tesamorelin) that raise GH and IGF-1 output.

Cognitive

Nootropic and neuro-active peptides (Semax, PT-141) explored for focus, mood and libido.

Cosmetic

Copper and signal peptides (GHK-Cu) used for skin, collagen and hair support.

Peptides at a glance

Typical starting doses from the literature — ranges vary by goal and individual, and are not a prescription.

Compound	Goal	Evidence	Typical dose
BPC-157	Recovery	◔ Preclinical	250 mcg
GHK-Cu	Cosmetic	◑ Limited human	2 mg
PT-141	Cognitive	◑ Limited human	1 mg
Retatrutide	Fat loss	◑ Limited human	2 mg
CJC-1295	GH	◑ Limited human	100 mcg
TB-500	Recovery	◔ Preclinical	2.5 mg
Semaglutide	Fat loss	● Clinical trials	0.25 mg
Tirzepatide	Fat loss	● Clinical trials	2.5 mg
Ipamorelin	GH	◑ Limited human	200 mcg
MOTS-c	Fat loss	◔ Preclinical	5 mg
Tesamorelin	GH	● Clinical trials	1 mg
Thymosin α-1	Recovery	◑ Limited human	1.6 mg
Semax	Cognitive	◔ Preclinical	300 mcg

⚠︎Educational information only — not medical advice. Many peptides are not approved for human use and may be legally restricted. Talk to a licensed clinician before starting anything. Reviewed by the Peptide Me editorial team · Last updated July 2026.

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Peptides — FAQ

Peptides are short chains of amino acids — the same building blocks that make up proteins, just smaller. In the body many act as signalling molecules that tell cells what to do, which is why different peptides target very different systems: tissue repair, metabolism, the growth-hormone axis, or skin and hair.

It depends entirely on the specific compound and your country. A few — like semaglutide and tirzepatide — are FDA-approved prescription medications. Many research peptides are legal to buy 'for research purposes' but are not approved for human use, and some are restricted. Always check your local regulations.

Approved compounds (the GLP-1 agonists, tesamorelin) require a prescription. Most research peptides are sold without one under a research-use label — which also means their purity and quality are not guaranteed. Third-party testing is strongly advised.

Most are reconstituted from a lyophilized (freeze-dried) powder with bacteriostatic water and injected subcutaneously using an insulin syringe. A few are taken orally, sublingually or applied topically. Our free reconstitution calculator works out the exact units to draw.

Anabolic steroids are synthetic hormones that act directly on androgen receptors. Peptides are amino-acid signalling molecules with a much wider range of targets and mechanisms — they are a different class entirely, though both are often used off-label and carry their own risks.

Every compound carries a badge: 'Clinical trials' (strong human data), 'Limited human' (small or early studies), or 'Preclinical' (animal/in-vitro only). It's there so nothing reads as more proven than it actually is.

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