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56 compounds, graded on evidence

Peptides, explained with the evidence.

What each peptide is, what people use it for, what the research actually shows and what can go wrong. Benefits and risks get the same space.

Browse the library Peptides 101
56
Compounds profiled
8
With strong human evidence
13
With animal data only, or none
17
Approved or prescribed somewhere
37
Prohibited in sport (WADA)

A closer look · BPC-157

From vial to molecule

GEPPPGKPADDAGLV
FIG. 3 · BPC-157, 15 residues

  1. 01 · The vial

    One vial. Fifteen amino acids.

    BPC-157 is a short peptide: a chain of 15 amino acids. Research suppliers ship it as a few milligrams of dry powder sealed in a small glass vial.

  2. 02 · The powder

    Freeze-dried, not dissolved.

    Lyophilised means freeze-dried. The peptide is dissolved in water, frozen, and the ice is then removed under vacuum, leaving a light, dry cake that keeps longer than a liquid would.

  3. 03 · Inside

    Up close, a chain of letters.

    Every molecule in the powder is the same sequence, written in one-letter amino acid codes: GEPPPGKPADDAGLV. The colours mark the chemical class of each residue.

    • Special (G, P)
    • Negative
    • Positive
    • Hydrophobic

  4. 04 · How it is thought to work

    How it is thought to work

    Proposed mechanism
    Promotes new blood vessel growth (angiogenesis) and tissue repair.
    Studied for
    Tendon, ligament, muscle and gut healing.

    Mechanisms seen in cells or animals do not always happen the same way in people.

  5. 05 · What the evidence shows

    Limited human evidence

    Evidence
    Limited: mostly animal; very few human studies.
    Approval
    Not approved anywhere. FDA flagged it as a compounding safety risk (2023).

  6. 06 · What can go wrong

    What can go wrong.

    Risk level5/10

    Unknown long-term; angiogenesis raises theoretical cancer concern.

    Read the BPC-157 profile Browse all 56 compounds

Browse by goal

Start with what you want to understand

Full library
9 Longevity & Anti-aging Mitochondrial peptides, bioregulators and senolytics. Mostly early research with small or animal-only data. 14 Growth Hormone & Muscle GH secretagogues, IGF-1 variants and myostatin blockers. Strong effects for some, thin proof and real risks for most. 4 Hormones & Testosterone Compounds that act on the LH, FSH and testosterone axis. Several are prescription drugs with clear uses. 7 Metabolic & Weight GLP-1 and related agonists plus fat-loss fragments. Home to the best-studied compounds in the library. 5 Recovery & Healing Tissue repair and inflammation peptides such as BPC-157 and TB-500. Popular, but mostly backed by animal data. 4 Cognitive & Brain Nootropic and neuro-repair peptides. Much of the research is Russian and small scale. 1 Sleep Peptides linked to deep sleep. Small human studies with mixed results. 1 Immune Immune-modulating peptides used as prescription medicines in some countries. 2 Libido & Bonding Melanocortin and hormone peptides that affect desire and social bonding. 2 Tanning & Pigment Melanocortin agonists that darken the skin. One is approved for a rare disease, the other is linked to mole changes. 3 Skin & Hair Cosmetic peptides used in creams and serums. Low risk on the skin, limited proof. 4 Non-peptide Adjuncts Compounds that are not peptides but are often sold or stacked with them, such as NAD+ and Urolithin A.

Most searched

All compounds
A laboratory bench by a window with a tray of vials, a notebook and an analytical balance
FIG. 3 Every profile is checked against published research before it goes in the library.

Strength ranking

The strongest are often the least tested

Each compound gets three separate scores, because one rating would hide the trade-off. Effect strength is how hard it acts on the body. Proof level is how well that is shown in humans. Risk level is how much can go wrong.

EffectProofRisk
Compare all compounds
  1. 01 RetatrutideMetabolic & Weight 10 7 6
  2. 02 TirzepatideMetabolic & Weight 9 10 5
  3. 03 HCGHormones & Testosterone 9 9 5
  4. 04 Melanotan IITanning & Pigment 9 3 7
  5. 05 SemaglutideMetabolic & Weight 8 10 5
  6. 06 HexarelinGrowth Hormone & Muscle 8 3 6
  7. 07 IGF-1 LR3Growth Hormone & Muscle 8 1 9
  8. 08 TriptorelinHormones & Testosterone 7 5 7
  9. 09 ACE-031Growth Hormone & Muscle 7 5 9
  10. 10 CJC-1295 (with DAC)Growth Hormone & Muscle 7 4 6

Before anything else

Four things the hype leaves out

01

Research peptides are unregulated

Most "research peptides" sold online have no quality control. Lab tests of these products often find the wrong amount, impurities or a different compound entirely.

02

Animal only means unknown

If a compound has only been tested in animals, its effects and safety in people are unknown. That is not the same as proven safe.

03

Growth signals do not pick targets

Growth-factor peptides such as IGF-1 variants, GH secretagogues, BPC-157 and TB-500 carry a theoretical risk of feeding cancers that already exist.

04

Supervision is not optional

Anyone using these compounds regularly needs medical supervision and bloodwork, such as IGF-1, glucose and HbA1c, hormones and lipids.

Read the safety basics

An open navy Limitless Lab box with three vials in a foam insert on a mahogany table in a bright apartment

What arrives

Sealed, labelled, packed to travel

  1. 01Each vial is closed with a crimped metal seal and a flip-off cap.
  2. 02The label shows the compound, the amount and the lot number.
  3. 03Vials rest in a fitted foam insert inside a rigid box.