The evidence for shape.
Retatrutide and the KLOW blend: the trials, the approvals, the gaps, the side effects, and what it means for you.
Studies on this page
21 fetched
each read from its source
A shape protocol here is built on retatrutide, with the repair blend added at week five. This page sets out what has actually been studied for each of them: who was in the trials, how many, for how long, what happened, and what nobody has looked at.
The two halves of this page are not comparable, and that is the honest headline. One compound has phase 2 and phase 3 trials with hundreds of participants. The other four have animal work, laboratory work, and in one case a two-person pilot. Read both columns.
Retatrutide
Retatrutide is a single molecule that acts on three receptors at once: the GIP receptor, the GLP-1 receptor and the glucagon receptor. The first two are the targets of the registered weight-loss medicines; the third is what makes this compound different, and it is the one associated with energy expenditure rather than appetite alone. It is given as a small weekly injection.
It has the largest and best-designed body of evidence of anything on this site. That is worth saying plainly, because it is not true of most of the other compounds here, and the difference between a phase 2 trial with hundreds of participants and a paper about rat tendons is the whole of what this wing exists to show.
What has been studied.
| Study | Who | n | How long |
|---|---|---|---|
| Lancet 20261phase 3 RCT | Adults with type 2 diabetes not controlled by diet and exercise alone, in the USA, Mexico and India | 930 | 40 weeks |
| The first phase 3 result to publish: HbA1c fell against placebo across three dose arms, with body weight as a key secondary endpoint. | |||
| Diabetes Obes Metab 20262phase 3 programme design | Adults with obesity, some with sleep apnoea or knee osteoarthritis | 5,800+ | Ongoing |
| Not a result: the published design of the four phase 3 trials, which is the honest status of most of what is claimed for this compound. | |||
| Lancet Diabetes Endocrinol 20253phase 2 RCT, substudy | Adults with type 2 diabetes, body composition measured by scan | substudy | 36 weeks |
| Total body fat mass fell against placebo and against the active comparator, measured by dual energy X-ray absorptiometry rather than by the scale. | |||
| Nat Med 20244phase 2a RCT, substudy | Adults from the obesity trial with fatty liver disease and at least a tenth of the liver as fat | 98 | 24 weeks of a 48-week study |
| Liver fat fell 42.9% in the lowest dose arm and 82.4% in the highest, against a rise of 0.3% on placebo; normal liver fat was reached by 86% in the highest arm and nobody on placebo. | |||
| N Engl J Med 20235phase 2 RCT | Adults with obesity, or overweight with a weight-related condition | 338 | 48 weeks |
| Weight fell in every dose arm against placebo, and the two highest dose arms lost 22.8% and 24.2% of body weight by 48 weeks. | |||
| Lancet 20236phase 2 RCT | Adults with type 2 diabetes on diet and exercise or a stable metformin dose | 281 | 36 weeks |
| Blood sugar and body weight both fell against placebo and against an active comparator across the dose range. | |||
What it is approved for.
- No approval anywhere was found on any page fetched for this build. The programme's own published design paper describes it as under clinical development for type 2 diabetes, obesity and related complications, and the first phase 3 result published in 2026. Source.
What has not been studied.
- Nobody has published a trial in a Filipino population, or in any South-East Asian population as a primary cohort. The phase 3 diabetes trial recruited in the United States, Mexico and India, which is the closest the fetched literature comes.
- Nobody has published beyond 48 weeks in obesity, which means the question every person on a 90-day protocol eventually asks, what happens in year three, has no published answer for this compound.
- Nobody has published it in combination with any other compound on this site. Every trial gave it alone against placebo or against a single active comparator.
- Nobody has published it in people who are not overweight, or in people whose goal is body composition rather than weight, or in trained athletes.
Side effects, and who stopped.
The side effects reported in the trials are gastrointestinal: nausea, diarrhoea, vomiting and constipation, mostly while the dose is rising and mostly described as mild to moderate. That pattern is the reason a protocol steps up slowly rather than starting where it intends to finish, and the reason nausea is treated on this site as a signal that the step came too early rather than as something to endure.
The trials report discontinuations, and dose-related gastrointestinal effects are the common reason. This is not a compound where nothing happens; it is a compound whose common effects are predictable and whose serious ones are the reason the quiz removes it entirely for a pancreatitis history, a thyroid cancer history, pregnancy or an active cancer.
WHAT THIS MEANS FOR YOU
The evidence for weight and for liver fat is the strongest on this site, and it is still phase 2 and phase 3 evidence in people with obesity or diabetes rather than in people who simply want to be leaner. Nothing in the published record tells you what it does in a Filipino body over years, because nobody has looked. It is a research material, not registered with the Philippine FDA and not approved for human use.
BPC-157
BPC-157 is a fifteen-amino-acid fragment of a protein found in gastric juice. It is the compound most associated with tendon, ligament and gut repair, and it is one of the four peptides in the blend that most protocols here add at week five.
It is also the clearest example of the gap this wing exists to show. The mechanism work is genuinely interesting and almost all of it is in animals and cells.
What has been studied.
| Study | Who | n | How long |
|---|---|---|---|
| Curr Rev Musculoskelet Med 20257narrative review, 2025 | The published literature, preclinical and clinical | n/a | n/a |
| An independent review of the whole literature. It describes regenerative effects across animal models and sets them against the regulatory position and the absence of human trials. | |||
| HSS J 20258systematic review, 2025 | The orthopaedic sports medicine literature to June 2024 | n/a | n/a |
| A systematic review from a sports medicine perspective. It states plainly that the compound lacks approval and is banned in professional sport while being increasingly used. | |||
| Altern Ther Health Med 20259pilot, human, intravenous | Two patients at a private clinic | 2 | 3 days |
| The smallest possible human study, and the only fetched one of intravenous use. Two people, blood work before and after, no efficacy endpoint. | |||
| J Appl Physiol (1985) 201110preclinical | Rat Achilles tendon tissue and cultured tendon cells | n/a | n/a |
| Tendon cell outgrowth and migration increased, and cell survival under oxidative stress improved. This is cell and animal work, not a human result. | |||
What it is approved for.
- None. A 2025 systematic review states plainly that it lacks United States Food and Drug Administration approval and that its use is banned in professional sport, while being increasingly used by clinicians and athletes. Source.
What has not been studied.
- There is no published randomised controlled trial of injected BPC-157 for a musculoskeletal injury in humans. The two 2025 reviews fetched here were written precisely because the compound is widely used and that trial does not exist.
- The only fetched human study of intravenous use had two participants and no efficacy endpoint at all.
- Long-term human safety data does not exist, in any population, at any duration.
Side effects, and who stopped.
There is not enough human data to describe a side-effect profile, which is itself the finding. The 2025 narrative review sets out to assess safety concerns and works from preclinical material because that is what there is.
WHAT THIS MEANS FOR YOU
The mechanism is plausible and the animal work is consistent, and that is a different thing from knowing it works in you. If you use it, use it knowing that you are ahead of the evidence rather than behind it, and that the reviews written by people who study this for a living say the same.
TB-500
TB-500 is sold as a fragment related to thymosin beta-4, a 43-amino-acid protein involved in cell migration and wound repair. The distinction between the fragment and the full-length protein is not a technicality here: it is the single most important thing on this page.
The human trials that exist, and several do, used full-length thymosin beta-4, applied to skin, to the eye, or given intravenously in a hospital. A laboratory analysis of the product sold as TB-500 identified a seven-amino-acid acetylated fragment instead.
What has been studied.
| Study | Who | n | How long |
|---|---|---|---|
| Cardiovasc Res 202511preclinical and clinical, 2025 | Mice, and people after a heart attack treated with stenting | Both | 28 days in mice |
| Recombinant full-length thymosin beta-4 improved cardiac function in mice and was carried into a group of patients after reperfusion. | |||
| Cornea 201512phase 2 RCT, eye drops | Patients with severe dry eye disease | 9 | 28 days with a 28-day follow-up |
| Signs and symptoms improved against vehicle control. Again the full-length peptide, and applied to the eye. | |||
| Drug Test Anal 201213laboratory analysis | The product sold as TB-500 | n/a | n/a |
| The paper that matters most for anyone buying this. Analysis of the product identified an acetylated seven-amino-acid fragment of thymosin beta-4, not the full-length peptide that the human trials used. | |||
| Ann N Y Acad Sci 201014phase 2 RCT, topical | Patients with venous stasis ulcers at eight European sites | 73 | Dose-escalation study |
| Full-length thymosin beta-4 applied to the skin. The safety profile at all doses was deemed acceptable. Note that this is the full-length peptide, not the fragment sold as TB-500. | |||
| Ann N Y Acad Sci 201015phase 1 RCT, intravenous | Healthy volunteers, four dose cohorts | 40 | Single dose then 14 daily doses |
| The human safety study of the full-length peptide given intravenously. Adverse events were infrequent and mild or moderate, with no dose-limiting toxicity. | |||
What it is approved for.
- None found on any page fetched for this build, for either the fragment or the full-length peptide. Source.
What has not been studied.
- Nobody has published a human trial of the seven-amino-acid fragment that the analysis found in the product. Every human trial fetched here used the full-length peptide.
- Nobody has published a human trial of either form injected under the skin for a musculoskeletal injury, which is how it is used.
- The dermal and ophthalmic trials were in wounds and dry eye, not in tendons.
Side effects, and who stopped.
The phase 1 intravenous trial of the full-length peptide in forty healthy volunteers reported adverse events that were infrequent and mild or moderate, with no dose-limiting toxicity and no serious adverse events. That is real safety data, and it is about a molecule that may not be the one in the vial.
WHAT THIS MEANS FOR YOU
Read the trial column on this page and then read the compound column, because they are not always the same molecule. What is known is that the full-length protein was tolerated intravenously in healthy volunteers and helped skin and eye conditions in small trials. What is not known is what the fragment does.
GHK-Cu
GHK is a three-amino-acid sequence that binds copper, present in human plasma and falling with age. It is the oldest and most-studied compound in the blend, with decades of laboratory work on collagen, elastin and gene expression behind it.
It is also the compound where the gap between mechanism and outcome is easiest to see, because the mechanism papers are strong and the one fetched randomised skin trial was negative.
What has been studied.
| Study | Who | n | How long |
|---|---|---|---|
| Bioimpacts 202516review, 2025 | The topical literature | n/a | n/a |
| A 2025 review of the peptide as a topical anti-wrinkle ingredient, which concludes that published information on skin permeability and effectiveness is insufficient. | |||
| Int J Mol Sci 201817review | The published literature on the copper tripeptide | n/a | n/a |
| A review from the group that originated the peptide, which is worth knowing when reading it. It sets out collagen and elastin synthesis, fibroblast support and gene expression work. | |||
| Genome Med 201218human tissue and computational | Lung tissue from smokers with emphysema, 64 samples from 8 lungs | 64 samples | n/a |
| A gene expression signature of lung destruction was reversed in fibroblasts by the tripeptide. This is the strongest mechanism paper and it is not a clinical outcome. | |||
| Arch Facial Plast Surg 200619RCT, topical | Patients after carbon dioxide laser skin resurfacing | 13 | 12 weeks |
| The fetched randomised skin trial, and it was negative: computer analysis and blinded evaluators found no significant difference between the groups. | |||
What it is approved for.
- None found as a medicine on any page fetched for this build. It is widely used as a cosmetic ingredient, which is a different regulatory category and not an approval. Source.
What has not been studied.
- No randomised trial of injected GHK-Cu for skin, in any population, was found. The fetched randomised trial applied it to the skin after laser resurfacing and found no significant difference.
- A 2025 review concludes that published information on skin permeability and effectiveness is insufficient, which is a review of the topical form, the one with the most data.
- Nothing on wrinkle outcomes over a year, nothing in Filipino skin, nothing on the injected form at all.
Side effects, and who stopped.
No safety signal appears in the fetched records, and no adequate human safety study of the injected form exists to produce one. Absence of reported harm from studies that were not done is not a safety finding.
WHAT THIS MEANS FOR YOU
The biology is real and well described; the clinical proof for skin is not there in the fetched record, and the one randomised skin trial was negative. If your skin changes on a protocol that contains it, that is worth noting in your own log, and it is not something the published literature would have predicted.
KPV
KPV is the last three amino acids of alpha-melanocyte-stimulating hormone, included in the blend for its anti-inflammatory action. It is the smallest and least-studied of the four.
What has been studied.
| Study | Who | n | How long |
|---|---|---|---|
| Gastroenterology 200820preclinical | Human intestinal cell lines, human T cells, and two mouse colitis models | n/a | n/a |
| The tripeptide reduced intestinal inflammation through a peptide transporter in cells and in mice. No human trial was found. | |||
| Inflamm Bowel Dis 200821preclinical | Two mouse models of inflammatory bowel disease | n/a | n/a |
| Anti-inflammatory activity in both models, including in mice with a non-functional melanocortin receptor. | |||
What it is approved for.
- None found on any page fetched for this build.
What has not been studied.
- No human trial of any kind was found. Both fetched papers are cell and mouse work in models of inflammatory bowel disease.
- Nothing on skin, nothing on tendon, nothing on the uses it appears in a blend for.
Side effects, and who stopped.
No human safety data was found, because no human study was found.
WHAT THIS MEANS FOR YOU
This is the compound on the shape and recovery protocols with the least evidence behind it, and it is a small part of a blend rather than something anyone takes alone. Knowing that is the point of this page. Take it to a doctor who knows you before you begin.
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Get startedWhat this adds up to.
For fat loss, the evidence is strong, recent, and about people rather than animals. Weight fell by around a fifth of body weight in the highest dose arms of the phase 2 obesity trial; liver fat fell by four fifths in the highest arm of the liver substudy; fat mass measured by scan fell in the diabetes substudy. Those are large effects from well-run trials, and they are the reason the compound is the core of almost every shape protocol built here.
For everything that joins at week five, the evidence is thin and the honest description is that people use it ahead of the data. That is a defensible position for an adult to take with a doctor who knows them, and it is not the same position as the one for the core compound, and this page exists so that nobody confuses the two.
What would change our mind.
A published randomised trial of injected BPC-157 for a tendon or ligament injury in humans would move the repair blend from plausible to shown, and it does not exist. A published trial of the seven-amino-acid fragment actually sold as TB-500 would tell us whether the human safety data for the full-length peptide transfers, and it does not exist either.
On the other side, a long-term safety signal in the retatrutide phase 3 programme would change what this site recommends, and the programme is running now. When either happens, this page changes. Every citation here carries the date it was read for that reason.
Questions
How strong is the evidence for retatrutide?
It has phase 2 trials in obesity and in type 2 diabetes with hundreds of participants each, a liver fat substudy, a body composition substudy measured by scan, and a first phase 3 result published in 2026. That is the strongest evidence base of anything on this site, and it is still short of the decades of use behind an old registered medicine.
Is BPC-157 proven?
Not in humans. The two 2025 reviews cited on this page were written because the compound is widely used and the human randomised trial does not exist. The animal and cell work is consistent; that is a different claim.
Why does TB-500 have a warning on this page?
Because a published laboratory analysis of the product sold under that name found a short acetylated fragment, while the human trials used the full-length 43-amino-acid protein. They are not the same molecule and the evidence for one does not carry to the other.
Has any of this been studied in Filipinos?
Not in the fetched record. No trial on this page recruited a Filipino population as its primary cohort. That gap runs across every compound on this site and it is the first entry on the page about what nobody knows.
Sources
Every record below was fetched on the date shown. Nothing on this page is cited that did not fetch.
- 01Bajaj HS, et al. Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial. Lancet 2026. PubMed 42250575 · doi · read 2026-09-07
- 02Giblin K, et al. Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials. Diabetes Obes Metab 2026. PubMed 41090431 · doi · read 2026-09-07
- 03Coskun T, et al. Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial. Lancet Diabetes Endocrinol 2025. PubMed 40609566 · doi · read 2026-09-07
- 04Sanyal AJ, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med 2024. PubMed 38858523 · doi · read 2026-09-07
- 05Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med 2023. PubMed 37366315 · doi · read 2026-09-07
- 06Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. Lancet 2023. PubMed 37385280 · doi · read 2026-09-07
- 07McGuire FP, et al. Regeneration or Risk? A Narrative Review of BPC-157 for Musculoskeletal Healing. Curr Rev Musculoskelet Med 2025. PubMed 40789979 · doi · read 2026-09-07
- 08Vasireddi N, et al. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS J 2025. PubMed 40756949 · doi · read 2026-09-07
- 09Lee E, et al. Safety of Intravenous Infusion of BPC157 in Humans: A Pilot Study. Altern Ther Health Med 2025. PubMed 40131143 · read 2026-09-07
- 10Chang CH, et al. The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. J Appl Physiol (1985) 2011. PubMed 21030672 · doi · read 2026-09-07
- 11Zhang Y, et al. Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion. Cardiovasc Res 2025. PubMed 41229390 · doi · read 2026-09-07
- 12Sosne G, et al. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. Cornea 2015. PubMed 25826322 · doi · read 2026-09-07
- 13Esposito S, et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal 2012. PubMed 22962027 · doi · read 2026-09-07
- 14Guarnera G, et al. The effect of thymosin treatment of venous ulcers. Ann N Y Acad Sci 2010. PubMed 20536470 · doi · read 2026-09-07
- 15Ruff D, et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci 2010. PubMed 20536472 · doi · read 2026-09-07
- 16Mortazavi SM, et al. Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective. Bioimpacts 2025. PubMed 39963574 · doi · read 2026-09-07
- 17Pickart L, et al. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. Int J Mol Sci 2018. PubMed 29986520 · doi · read 2026-09-07
- 18Campbell JD, et al. A gene expression signature of emphysema-related lung destruction and its reversal by the tripeptide GHK. Genome Med 2012. PubMed 22937864 · doi · read 2026-09-07
- 19Miller TR, et al. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg 2006. PubMed 16847171 · doi · read 2026-09-07
- 20Dalmasso G, et al. PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation. Gastroenterology 2008. PubMed 18061177 · doi · read 2026-09-07
- 21Kannengiesser K, et al. Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Inflamm Bowel Dis 2008. PubMed 18092346 · doi · read 2026-09-07
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