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PEPTIDE READER

Recovery & strength

Peptides for muscle growth and strength

Seven of the twelve entries here are sold on the gray market, and nothing on this page is approved for building muscle in a healthy person anywhere.

The evidence mix

The 12 peptides on this page, by how well they have been tested.

  1. Approved medicine4 peptides
  2. Still being tested in people2 peptides
  3. Tested in people, but barely6 peptides
  4. Only tested on animalsnone on this page
  5. No real evidence at allnone on this page
How we grade evidence

Most of them do raise growth hormone, and that part is measured and real. What happens next is the problem: where a study went on to measure muscle, strength or physical performance, it found no change. The clearest case is growth hormone itself — pooling 27 randomised comparisons in 303 fit young people, lean tissue rose and strength and exercise capacity did not improve. For several of the others nobody has ever measured it at all. The four approved medicines here are licensed for growth disorders, for a rare hormone deficiency in children, for a specific fat problem in HIV, and for an ultra-rare genetic disease — and the last of those was approved even though knee strength did not improve during its randomised trial. The twelfth is a food supplement, and most of the exercise evidence attached to it comes from studies that gave people a different compound — the building block the body converts into it — rather than the supplement itself.

All 12 peptides on this page

Strongest evidence first.

Filter these in the full register

Approved medicine

Approved by the European or US medicines regulator for a named condition, after large randomised trials, with a public product information sheet anyone can read.

4 peptides

  1. Evidence level 5 of 5: Approved medicine

    IGF-1 (insulin-like growth factor 1)

    Insulin-like growth factor 1 · Insulin-like growth factor-I

    Approved as mecasermin for a rare growth disorder in children, and sold separately online as IGF-1 LR3 for muscle growth.

    The approved use compares children with their own growth before treatment, not with a placebo group; the IGF-1 LR3 sold for muscle has never been given to a person in a published study.

    Sold as: Therapeutic

  2. Evidence level 5 of 5: Approved medicine

    Somatropin

    Recombinant human growth hormone · rhGH

    Approved for growth failure in children and growth hormone deficiency in adults, and promoted far beyond that for anti-ageing, fat loss and muscle.

    Randomised trials support the approved uses; in healthy adults it shifted fat and lean tissue without improving strength, endurance or function.

    Sold as: Therapeutic

  3. Evidence level 5 of 5: Approved medicine

    SS-31 (elamipretide)

    Elamipretide · Elamipretide hydrochloride

    Approved in the United States to improve muscle strength in Barth syndrome, an ultra-rare inherited disease, and sold online as a mitochondria and anti-ageing peptide.

    Its largest trials, in mitochondrial myopathy, heart failure and eye disease, all failed; the approval rests on a strength measure that did not move against a dummy injection.

    Sold as: Therapeutic

  4. Evidence level 5 of 5: Approved medicine

    Tesamorelin

    Egrifta · Egrifta SV

    Approved in the United States to shrink the deep belly fat of adults with HIV-related lipodystrophy, and promoted elsewhere for fat loss, muscle and anti-ageing.

    Two large placebo-controlled trials measured the fat reduction; Europe's regulator judged the same data did not show any health benefit and never approved it.

    Sold as: Therapeutic

Still being tested in people

Currently in registered clinical trials in humans, but not approved anywhere yet. The trials may still fail — most drugs at this stage do.

2 peptides

  1. Evidence level 4 of 5: Still being tested in people

    Ipamorelin

    NNC 26-0161

    Promoted for muscle growth and recovery, although its human trials studied bowel recovery after surgery.

    It reached mid-stage trials, but the programme ended and the results were never published.

    Sold as: Gray market

  2. Evidence level 4 of 5: Still being tested in people

    MK-677 (ibutamoren)

    Ibutamoren · Ibutamoren mesylate

    Promoted for muscle growth, better sleep and slower ageing through higher growth hormone levels.

    Trials raised the hormone every time and changed nothing measurable: no more strength, no better function, no effect on the diseases it was tested against.

    Sold as: Gray market

Tested in people, but barely

Human studies exist, but they are small, short, uncontrolled, paid for by the seller, or they measure something easy to measure instead of something that matters.

6 peptides

  1. Evidence level 3 of 5: Tested in people, but barely

    Carnosine

    L-carnosine · beta-alanyl-L-histidine

    Sold as a supplement for ageing, exercise performance and eye health.

    Blood sugar came down against a dummy capsule in two small trials, but an enzyme in blood destroys it within minutes, most of the exercise evidence is really about beta-alanine, and pooled autism trials found no difference from placebo.

    Sold as: Supplement

  2. Evidence level 3 of 5: Tested in people, but barely

    CJC-1295

    CJC-1295 with DAC · CJC-1295 without DAC

    Promoted for muscle growth, strength and recovery through higher growth hormone levels.

    Short studies measured hormone levels, but none showed more muscle, greater strength or faster healing.

    Sold as: Gray market

  3. Evidence level 3 of 5: Tested in people, but barely

    GHRP-2

    Pralmorelin · Pralmorelin (INN)

    Approved in Japan only as a one-off injection for diagnosing growth hormone deficiency; promoted online for muscle, appetite and recovery.

    It reliably releases growth hormone and demonstrably makes people eat more, but no study has ever measured muscle, strength or body fat in a person taking it.

    Sold as: Gray market

  4. Evidence level 3 of 5: Tested in people, but barely

    GHRP-6

    Growth hormone-releasing peptide 6 · Growth hormone-releasing hexapeptide

    Promoted for muscle growth and for appetite, and sold as a research chemical.

    Human studies measured hormones in blood for a couple of hours after a single dose; none tested it as a treatment for anything.

    Sold as: Gray market

  5. Evidence level 3 of 5: Tested in people, but barely

    Hexarelin

    Examorelin · Examorelin (INN)

    Promoted for muscle growth and recovery through higher growth hormone levels.

    The one study that gave it for 16 weeks and scanned people found no change in muscle, fat, bone or IGF-1.

    Sold as: Gray market

  6. Evidence level 3 of 5: Tested in people, but barely

    Sermorelin

    Geref · sermorelin acetate

    Sold by anti-ageing and hormone clinics, and online, to raise growth hormone for muscle, fat loss and sleep.

    It was an approved medicine until 2009, but the uses it is sold for now were either never measured or measured once and found unchanged.

    Sold as: Gray market