Weight management
PTT-A
Experimental peptide tetra-agonist
An experimental peptide targeting four hormone receptors. Its weight and muscle findings are from animals so far.
Early research
VETUD / Education
Peptides, explained simply.
Plain-language guides to 42 peptides and related compounds, from approved medicines to early research. What they are, what studies found, how far they’ve got, and what’s still unknown.
All peptide guides: 42
Weight management
CBL-514
A small molecule, not a peptide, studied for reducing local fat deposits by triggering fat-cell death.
In human trials
Weight management
Semaglutide
Ozempic, Wegovy, Rybelsus
A copy of a gut hormone that makes you feel full. One of the most studied weight-loss medicines in the world.
Approved medicine
Weight management
Tirzepatide
Mounjaro, Zepbound
Works on two gut hormones at once, GLP-1 and GIP. In trials it led to some of the biggest weight losses seen with an approved medicine.
Approved medicine
Weight management
Retatrutide
LY3437943, often called “triple G”
An experimental “triple” hormone medicine that has produced some of the largest weight losses ever seen in a drug trial.
In human trials
Weight management
Liraglutide
Victoza, Saxenda
The older, once-a-day cousin of semaglutide, and the first GLP-1 medicine approved for weight management.
Approved medicine
Weight management
Cagrilintide
Half of CagriSema
A copy of amylin, a fullness hormone, being developed alongside semaglutide.
In human trials
Weight management
AOD-9604
HGH fragment 176-191
A small piece of growth hormone that was developed as a fat-loss drug, but never made it to approval.
In human trials
Skin & copper peptides
GHK-Cu
Copper peptide
A copper-carrying peptide found in skin care for its anti-aging effects.
Early research
Skin & copper peptides
Argireline & Snap-8
Acetyl hexapeptide-8 and acetyl octapeptide-3
The “Botox in a jar” peptides: skin-care ingredients designed to soften expression lines.
Early research
Pigmentation
Melanotan I & II
Afamelanotide (Melanotan I)
The “tanning peptides”. One is an approved medicine for a rare disease; the other is an unapproved tanning injection that doctors warn about.
Early research
Pigmentation
Decapeptide-12
Lumixyl peptide
A skin-care peptide that slows the making of melanin, studied for dark patches such as melasma.
Early research
Hair
AHK-Cu
Copper tripeptide-1
A copper-carrying peptide, cousin of GHK-Cu, studied for hair growth.
Early research
Recovery & mobility
BPC-157
Body Protection Compound-157
A popular “healing” peptide with lots of animal research behind it, and almost no proper studies in people.
Early research
Recovery & mobility
TB-500
Thymosin beta-4 fragment
A small piece of a natural repair protein. Popular for recovery, but barely tested in people.
Early research
Recovery & mobility
KPV
Lys-Pro-Val
A tiny peptide of three amino acids, studied for calming inflammation in the gut.
Early research
Recovery & mobility
ARA-290
Cibinetide
A small peptide made from a part of EPO that protects tissues, studied for nerve damage.
In human trials
Energy & metabolism
MOTS-c
A peptide made inside mitochondria, the cell’s power plants, and studied for metabolism.
Early research
Energy & metabolism
NAD+
Nicotinamide adenine dinucleotide
Not a peptide, but often mentioned alongside them: a molecule every cell needs to make energy.
Early research
Energy & metabolism
SS-31
Elamipretide, Forzinity
The first approved medicine that targets the mitochondria, the cell’s power plants.
Approved medicine
Energy & metabolism
SLU-PP-332
Often called an “exercise pill”
Not a peptide: a lab compound that makes mice’s muscles behave as if they had exercised.
Early research
Energy & metabolism
5-Amino-1MQ
Not a peptide: a small compound that blocks an enzyme linked to fat storage, studied in mice.
Early research
Performance & growth
Ipamorelin
A peptide that nudges the body to release its own growth hormone.
In human trials
Performance & growth
CJC-1295
A long-lasting version of the brain signal that triggers growth hormone.
In human trials
Performance & growth
Sermorelin
Geref
A short copy of the brain’s growth-hormone signal that was once a prescription medicine for children.
Formerly approved
Performance & growth
Tesamorelin
Egrifta
A growth-hormone-releasing medicine studied for changes in visceral fat, the deep fat around the organs.
Approved medicine
Performance & growth
Growth hormone (HGH)
Somatropin
The body’s own growth hormone, made in the lab: a proven medicine for real deficiency, and widely misused.
Approved medicine
Performance & growth
IGF-1 LR3
Long R3 IGF-1
A long-lasting lab version of IGF-1, the hormone growth hormone works through.
Early research
Concentration & focus
Semax
A Russian nasal-spray peptide used after strokes and studied as a “brain booster”.
Approved in some countries
Calm & balance
Selank
A nasal-spray peptide developed in Russia and studied for anxiety.
Approved in some countries
Sleep
DSIP
Delta sleep-inducing peptide, emideltide
A small brain peptide named for deep sleep, whose effect still isn’t clear after 50 years.
Early research
Longevity
Epitalon
Epithalon
A four-amino-acid peptide studied for aging and telomeres, mostly in cells and animals.
Early research
Sexual health
PT-141
Bremelanotide, Vyleesi
An approved medicine that works in the brain to increase sexual desire.
Approved medicine
Fertility & hormones
Kisspeptin
The hormone that switches on the reproductive system, being tested as a gentler way to trigger egg maturation in IVF.
In human trials
Fertility & hormones
hCG
Human chorionic gonadotropin, Pregnyl, Ovidrel
The pregnancy hormone: an approved fertility medicine, and the center of a long-running weight-loss myth.
Approved medicine
Fertility & hormones
FSH
Follicle-stimulating hormone, follitropin
An approved fertility hormone that helps eggs develop during IVF.
Approved medicine
Immune support
Thymosin alpha-1
Thymalfasin, Zadaxin
A natural immune-signaling peptide from the thymus gland, used as a medicine in some countries.
Approved in some countries
Immune support
VIP
Vasoactive intestinal peptide, aviptadil
A natural messenger peptide that relaxes blood vessels and calms inflammation, studied in lung disease.
In human trials
Classic medicines
Insulin
The most famous peptide medicine of all. It turned type 1 diabetes from a fatal disease into a manageable one.
Approved medicine
Classic medicines
Oxytocin
Pitocin, Syntocinon
The “bonding hormone”, and one of the most used medicines in childbirth.
Approved medicine
Classic medicines
Octreotide
Sandostatin, Mycapssa
A long-lasting copy of a natural “brake” hormone, used to control some hormone disorders and tumors.
Approved medicine
Classic medicines
Teriparatide
Forteo, Forsteo
A bone-building peptide that cuts the risk of spine fractures in osteoporosis.
Approved medicine
Results
What the weight-loss trials found.
Published human trial averages, plus early findings for PTT-A and CBL-514 with the type of evidence clearly identified.
Each medicine compared with a placebo in its own trial. Ordered by reported average; this is not a head-to-head ranking.
- Medicine
- Placebo
Retatrutide · Experimental
12 mg weekly
Phase 2 · 48 weeks · 338 people
24.2%
2.1%
Tirzepatide · Approved
15 mg weekly (Zepbound)
SURMOUNT-1 · 72 weeks · 2,539 people
20.9%
3.1%
Semaglutide · Approved
2.4 mg weekly injection (Wegovy)
STEP 1 · 68 weeks · 1,961 people
14.9%
2.4%
Semaglutide · Approved (US)
25 mg daily pill (Wegovy pill)
OASIS 4 · 64 weeks · 307 people
13.6%
2.2%
Average body weight lost
Each human trial had different people, doses and lengths, so compare with care. The bars describe approved or experimental medicines studied under medical supervision with diet and exercise advice, not laboratory research products. They use full journal reports; conference findings and different endpoints appear separately below.
Show these numbers as a table
| Medicine | Trial | People | Weeks | Medicine | Placebo | Source |
|---|---|---|---|---|---|---|
| Retatrutide, 12 mg weekly | Phase 2 | 338 | 48 | 24.2% | 2.1% | PubMed |
| Tirzepatide, 15 mg weekly (Zepbound) | SURMOUNT-1 | 2,539 | 72 | 20.9% | 3.1% | PubMed |
| Semaglutide, 2.4 mg weekly injection (Wegovy) | STEP 1 | 1,961 | 68 | 14.9% | 2.4% | PubMed |
| Semaglutide, 25 mg daily pill (Wegovy pill) | OASIS 4 | 307 | 64 | 13.6% | 2.2% | PubMed |
PTT-A and CBL-514: evidence so far
Neither has a comparable average human body-weight-loss result in the research below. Animal body weight and human fat volume measure different things, so they are shown separately from the bars.
Animal research · conference abstract
PTT-A
- Average human body-weight loss
- Not established in the cited research
- What was measured
- Body weight in diet-induced obese rats over 21 days
- Reported finding
- Body weight was 19.2% lower versus vehicle at the higher studied exposure; tirzepatide was 12.1% lower versus vehicle in the same experiment.
A difference versus vehicle in rats is not average weight lost by people. It cannot establish superiority to retatrutide in humans.
Human fat-volume subgroup · conference report
CBL-514
- Average human body-weight loss
- Not established by this fat-volume result
- What was measured
- MRI-measured visceral-fat volume, four weeks after final treatment
- Reported finding
- Visceral-fat volume fell 12.01%; placebo rose 5.68%. The small phase 2 subgroup had 40 participants with later follow-up data.
12.01% less visceral fat is not 12.01% less body weight. CBL-514 is an experimental small molecule, not a peptide.
Learning guides
Make sense of the evidence.
Start with the research stages, then learn how to compare the results a study actually measured.
GuideReading the evidence
From cells to people: understand the research stages
A promising mechanism, an animal experiment and a human trial answer different questions. Here is how to tell which kind of evidence you are reading.
GuideReading the evidence
Body weight, fat and muscle: read the right result
A percentage means little without its denominator. Learn why changes in body weight, a fat deposit and a measurement in rats belong in different comparisons.
News & articles
New research, explained.
Recent studies and decisions, written so anyone can follow them, with every source linked.
StudyWeight management
PTT-A targets four receptors. The evidence is still in animals
The experimental peptide combines GLP-1, GIP, amylin and calcitonin activity. Here is what the original research can tell us about weight loss.
StudyPerformance & growth
Tesamorelin cut deep belly fat by 15% in its main trial
The growth-hormone-releasing medicine is approved for a narrow use in people with HIV. A later trial measured liver fat too.
StudyPerformance & growth
Growth hormone in healthy older adults: a little more muscle, the same weight, more side effects
A systematic review of randomized trials found small changes in body composition and higher rates of swelling and joint pain. Its authors could not recommend it against aging.
Videos
Watch, then explore the evidence.
43 selected YouTube videos from clinicians, researchers, hospitals and science educators. Each profile and article has its own connected selection.
Ohio State Wexner Medical Center
What is a GLP-1 agonist, and how does it work?
A hospital explainer of GLP-1 signalling, appetite and blood-sugar regulation.
Allison L. Rhodes, MD · obesity medicine
Watch on YouTubekhanacademymedicine
The hypothalamus and pituitary gland
How the hypothalamus and pituitary coordinate hormone release, including growth and reproductive hormones.
Khan Academy · endocrine physiology
Watch on YouTubeNational Institute of Mental Health
What is clinical research?
Why studies in people are needed and what clinical research is designed to establish.
NIMH · US National Institutes of Health
Watch on YouTube
The basics.
What is a peptide?
A short chain of amino acids, the same building blocks that make up proteins. Insulin, oxytocin and the new weight-loss medicines are all peptides.
Approved or not?
An approved medicine has passed large trials and been checked by a regulator such as the FDA. Many popular peptides have only been tested in cells or animals. Every page here says which is which.
Reading a result
Results are averages from trials. A placebo group, which gets a dummy treatment, shows how much change happens anyway. The difference between the two is what the medicine did.
mg and ml
Milligrams (mg) measure weight. Millilitres (ml) measure liquid. A 10 mg vial and a 10 ml bottle are different things, and can’t be compared directly.
VETUD Learn explains published research in plain language. It is general information, not medical advice. Talk to a doctor before starting, stopping or changing any treatment.