Peptides

Approved for advanced prostate cancer, as the fast-acting alternative to the older hormone-blocking injections.

Large trials show it removes testosterone in days rather than weeks, but the trial built to prove it is kinder to the heart stopped early without an answer.

Approved to control water balance and to treat specific bleeding disorders.

It is an established prescription medicine with approved uses and decades of clinical experience.

Approved for type 2 diabetes, and in the US also for reducing heart attacks and strokes in people who already have it — but not approved anywhere for weight loss.

Ten randomised trials and a 9,901-person heart trial support the diabetes and heart claims; the weight it takes off is real but small, about 3.2 kg against 1.5 kg on dummy injections.

Approved for type 2 diabetes since 2005, and the first medicine of its kind anywhere — a synthetic copy of a lizard peptide, not a human hormone.

Placebo-controlled trials show lower blood sugar and one to two kilograms of weight loss, but the 14,752-person heart trial missed its target and newer weekly injections beat it in head-to-head trials.

Approved for prostate cancer, breast cancer, endometriosis, fibroids and thinning the lining of the womb before surgery.

Large randomised trials with real comparison groups, including one where adding it to radiotherapy left 58% of men alive at ten years against 40%.

Approved for fertility treatment and for low testosterone in men, and promoted separately for weight loss and for restarting testosterone after steroids.

The approved uses rest on regulator-grade evidence; for weight loss it did not beat a dummy injection, and the US label has said so since 1974.

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.

Approved to control blood sugar in people with diabetes.

Its benefits and risks are supported by large, long-running clinical trials and routine medical use.

Approved for prostate cancer and other conditions controlled by sex hormones.

It is an established prescription medicine with approved uses and long-term clinical data.

Approved for type 2 diabetes and weight management.

Large controlled trials show lower blood sugar and weight loss compared with placebo.

Approved for acromegaly and symptoms caused by certain hormone-producing tumours.

It is an established prescription medicine supported by clinical trials and decades of use.

Approved to start and strengthen labour and to control bleeding after birth; promoted separately, as a nasal spray, for trust, bonding and connection.

The childbirth use is long-established, while the largest trial of the social claims ended level with a dummy spray.

Approved for low sexual desire that causes distress, in women who have not been through the menopause.

Two large randomised trials found a real but small gain in desire and a drop in distress, while the number of satisfying sexual encounters did not change.

Approved for type 2 diabetes and weight management.

Large controlled trials show lower blood sugar, substantial weight loss and fewer cardiovascular events in specific groups.

Approved for obesity caused by hypothalamic damage, Bardet-Biedl syndrome or three named gene faults — not for ordinary obesity.

One randomised trial found BMI fell about 16 per cent against a 3 per cent rise on a dummy injection; the trials in the genetic conditions had 10 to 44 people and mostly no comparison group.

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.

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.

Approved for osteoporosis to strengthen bone and reduce fractures.

Large controlled trials show fewer spinal and non-spinal fractures in people at high risk.

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.

Approved in Italy only as a helper for flu vaccination in adults with a weak immune system, and promoted far more widely for immunity, inflammation, long COVID and ageing.

The largest trial, in 1,106 adults with sepsis, matched dummy injections on every outcome including the immune marker the drug is supposed to raise.

Approved for type 2 diabetes and weight management.

Large controlled trials show lower blood sugar and substantial weight loss compared with placebo and other treatments.

Being studied for weight loss, mainly in combination with semaglutide.

Large late-stage trials exist for the combination, but cagrilintide on its own is not an approved medicine.

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.

Approved in China for weight loss and type 2 diabetes, and experimental everywhere else.

Four published phase 3 trials show large weight loss and lower blood sugar against dummy injections, all of them run in China.

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.

Being studied for weight loss and for fatty liver disease; not approved anywhere.

The liver trial cleared inflammation against dummy injections but missed its second target, the scarring, and the 48-week weight-loss results have never been published in a journal.

Being studied for weight loss and type 2 diabetes.

Human trials show large weight changes, but it remains experimental and is not approved.

Being studied for weight loss and fatty liver disease.

Large human trials have measured changes in weight and liver disease, but it is not an approved medicine.

Sold in skincare for expression lines and wrinkles.

The studies are small and short, and one independent trial finished without publishing results.

Promoted for fat loss, and increasingly for joints, cartilage and anti-ageing.

A 502-person trial found no more weight loss than dummy tablets, and the injected form people buy has never been tested in anyone.

Promoted for injury recovery, tendon healing and gut problems.

Human evidence is limited to a 12-person case series and a two-person pilot with no comparison group.

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.

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 a supplement for skin, hair, bones and joints.

Small human trials report some skin and joint changes, but many were funded by the industry selling the products.

Promoted for slowing ageing and extending lifespan.

The human studies are small, come from one research tradition and have not been independently repeated.

Sold in skincare for wrinkles, skin repair and hair growth.

Human studies are small, and the only blinded objective measurement found no clear benefit.

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.

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 an antioxidant supplement, and as a drip into a vein for lightening skin.

Most of a swallowed dose is broken down before it reaches the blood, the placebo-controlled skin trials are small and disagree, and the drip has no adequate trial behind it.

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.

Promoted for libido, fertility and testosterone, and sold as a compounded injection.

It shifts reproductive hormones within minutes, but the one placebo-controlled course lasting weeks failed to raise testosterone.

Sold in fermented milk drinks and supplements for blood pressure.

Europe's food safety authority assessed the blood pressure claim twice and concluded a cause-and-effect relationship had not been established.

Sold online for infections, wound healing and gut problems; a peptide the body makes itself.

The one properly controlled trial, in 148 people with leg ulcers, closed no more wounds than a dummy gel.

Sold online as a tanning injection, and separately as something that produces erections.

Two placebo-controlled studies in 20 men found it produces erections; the tanning evidence is one pilot in three men, and the harms are single case reports.

Sold in anti-wrinkle skincare.

The main human study was small and linked to the ingredient's commercial development.

Sold in skincare blends for wrinkles and irritated-looking skin.

No peer-reviewed human study has tested this ingredient on its own.

Sold in skincare to support collagen and soften wrinkles.

The evidence comes from two small experiments submitted by the raw-material supplier.

Sold online as an anti-anxiety and focus spray; a prescription medicine in Russia only.

The human studies are small, were compared only against tranquillisers rather than a dummy, and all come from the institutes that invented it.

Approved in Russia as nasal drops for poor blood flow in the brain; promoted elsewhere as a focus and memory drug.

Every published human study used the nose, most had no comparison group, and the two the US regulator could read in English found no effect.

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 in skincare for expression lines and wrinkles, as the longer version of Argireline.

No published study has tested it on its own, and the wrinkle percentages it is sold on come from the ingredient maker.

Sold for gut inflammation, skin conditions and wound healing.

No published study has ever given it to a person; the evidence is mouse, rat and rabbit experiments and cells in dishes.

Promoted for weight loss, exercise performance and longer life.

The published evidence comes from cells and animals; there are no completed treatment trials in people.

Promoted for injury healing and recovery.

There are no controlled human studies of TB-500 itself; the evidence comes from animals and related molecules.

Sold in eye creams for puffiness and dark circles.

No peer-reviewed clinical study of this ingredient has been published.