Five fat-loss peptides that aren’t Ozempic, ranked by evidence

This is the written version of 5 Fat-Loss Peptides That Aren’t Ozempic, Graded A To E — watch it instead if you’d rather.

In process engineering there is a specific kind of meeting I have sat through more times than I would like. Somebody presents a beautiful mechanism — a clever bit of chemistry that ought to solve the problem — and everybody nods, and then someone at the back asks whether it has ever been run on a real plant, and the room goes quiet. A mechanism is a hypothesis. A commissioning report is evidence. They are not the same thing and the gap between them is where most of the money gets lost.

The non-GLP-1 fat-loss peptides are that meeting, held over and over again. Every one of them has a mechanism you can draw on a whiteboard and feel clever about. Only some of them have ever been run on a real plant. So this ranking has exactly one rule: I am not ranking by how loud a compound is, I am ranking by how much human evidence actually holds it up. It is remarkable how often those two run in opposite directions.

Fifth: AOD-9604, the mechanism that lost to salt water

On paper AOD-9604 is gorgeous, and I mean that sincerely. It is a snipped-off fragment from the tail end of human growth hormone — the fat-mobilising bit kept, the bit that makes tissue grow discarded. That is elegant molecular editing: take the function you want, leave the side effect you don’t. Reading the marketing, you would think somebody had bottled liposuction.

Then you open the commissioning report. AOD-9604 went through six human trials, including two Phase IIb efficacy studies enrolling 300 and 500 adults with obesity. The signal that showed up in the early, looser studies did not survive the final, better-controlled one, which added a proper diet and exercise regime to both arms. Put plainly: once you controlled the trial properly, the compound could not beat a placebo injection.

What happened next is the part I find genuinely instructive. The drug programme was shelved — and AOD-9604 was subsequently granted GRAS status as an ingredient for foods, drinks and dietary supplements. It did not get better. It changed regulatory category, which is a very different thing, and one that a marketing page will never explain to you. Gorgeous mechanism, empty report card. This is where the hype and the reality file for divorce.

Fourth: 5-Amino-1MQ, brilliant — in mice

This one is properly clever. It inhibits an enzyme called NNMT, and the cleanest way to picture NNMT is as a handbrake on the fat cell’s own metabolism. Block the enzyme and you release the brake, so the cell burns its own fuel instead of hoarding it. In diet-induced obese mice, a potent NNMT inhibitor did exactly what the theory predicts: bodyweight down, white fat mass down, fat cells smaller, cholesterol down — and, notably, without the animals eating any less. The mechanism is real and the mouse data is not junk.

Here is the catch, and it is the whole catch. Those are mice. Human efficacy trials are, at the time of writing, essentially absent. Every glowing “this gave me incredible energy” testimonial online is one uncontrolled person with expectations, not a controlled study — and you are not a thirty-gram rodent on a designer diet in a temperature-controlled room.

Promising is a fair word for it. Proven is not. If you want the longer version of why mouse data flatters a compound so reliably, the KPV write-up is the same problem in a different molecule.

Third: CJC-1295 and ipamorelin, a real lever with no receipts

The classic tag team. Rather than injecting growth hormone directly, these two persuade your own pituitary to release more of it — one holds the door open, the other gives it a shove. And that part is not in dispute. In healthy adults, a single administration of CJC-1295 raised mean growth hormone concentrations several-fold for six days or more, with IGF-1 elevated for well over a week. Measurable, repeatable, real.

The leap of faith is the next step: assuming that more growth hormone therefore equals meaningful fat loss in you. That inference is doing enormous work, and the direct trials that would test it — randomised, placebo-controlled, fat loss as the endpoint — are simply not there. Running IGF-1 elevated for months is also not a free lunch; it is a systemic signal, not a targeted one.

So this is a genuine lever, and I would not call it snake oil. We just do not have the receipts that pulling it melts fat the way the reels promise. Raising a biomarker is not the same as changing an outcome, and that distinction is most of what separates a supplement from a medicine.

Second: tesamorelin, the best evidence — for a narrower job

Now we are in grown-up territory. Tesamorelin is the only compound on this list with an actual regulatory approval behind it: the FDA approved it in November 2010, and in randomised placebo-controlled trials it reduces visceral adipose tissue — the deep fat packed around the organs — by a real, measurable amount. Across the Phase III programme, visceral fat fell by roughly 15 to 20 per cent over six to twelve months, and a systematic review of placebo-controlled growth-hormone-axis trials found a consistent visceral-fat reduction with no meaningful effect on the subcutaneous fat you can actually pinch.

Best evidence on the board — for a much narrower job than the thumbnails suggest.

So why isn’t it number one? Two catches, and the label states both of them plainly. First, the approval is for the reduction of excess abdominal fat in adults with HIV-associated lipodystrophy. For anyone outside that population you are extrapolating from a trial that was never run on you. Second — and this is written into the prescribing information as a Limitation of Use — it is not indicated for general weight-loss management, and its long-term cardiovascular safety has not been established.

Read that again, because it is unusual. The regulator has explicitly told you what this drug is not for, and the internet has decided to use it for that anyway.

First: tesofensine, which isn’t a peptide

Tesofensine began life as a candidate treatment for Alzheimer’s and Parkinson’s disease. It failed at that. But the researchers noticed something in the data they were not looking for: the patients kept losing weight. That is one of my favourite kinds of scientific accident — the negative result that contains a different positive one.

So they ran it properly. In a Phase II randomised, double-blind, placebo-controlled obesity trial across five Danish centres, 203 adults with obesity were put on an energy-restricted diet and randomised to tesofensine or placebo for 24 weeks. Diet plus placebo produced about 2 per cent weight loss. Tesofensine at the higher levels tested produced roughly 9 to 10 per cent — more than most of the rest of this list combined, and the authors themselves noted it looked like about twice the effect of the approved drugs of the day.

Two catches, though. It works like a stimulant — it holds three monoamine neurotransmitters switched on at once — and the trial recorded dry mouth, nausea, constipation, insomnia and a measurable rise in heart rate. And second, my favourite: it is not a peptide. It is a small molecule that got adopted into the peptide crowd because it hangs out in the same group chat. The most effective thing on the peptide list is not, in fact, a peptide.

The bottom line

Rank these by volume and you get one order. Rank them by evidence and you get almost the reverse. AOD-9604 is loud and empty. 5-Amino-1MQ is quiet, clever and untested in humans. CJC-1295 with ipamorelin moves a number that may or may not move the outcome you care about. Tesamorelin has the paperwork — for a population and a fat compartment most people asking about it do not have. And tesofensine has the biggest raw number, a pile of asterisks, and the wrong molecular passport.

None of this is a shopping list. It is a filter, so you can tell the mechanism from the marketing. And it is worth being honest about the shadow over the whole page: the GLP-1 side of this field, which this ranking deliberately excludes, has far stronger and far larger human evidence than anything on it. If you want that side of the story, the retatrutide write-up covers the biggest number this drug class has ever produced and the fine print underneath it — and if you are thinking about what happens when people stop, coming off GLP-1s is the honest sequel.

Sources

1. Stier H, Vos E, Kenley D, “Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans”, Journal of Endocrinology and Metabolism, 2013 — https://jofem.org/index.php/jofem/article/view/157
2. Moré MI, Kenley D, “Safety and Metabolism of AOD9604, a Novel Nutraceutical Ingredient for Improved Metabolic Health”, Journal of Endocrinology and Metabolism, 2014 — the trial programme and its GRAS supplement outcome — https://jofem.org/index.php/jofem/article/view/213
3. Neelakantan H et al., “Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice”, Biochemical Pharmacology, 2017 — https://pmc.ncbi.nlm.nih.gov/articles/PMC5826726/
4. Teichman SL et al., “Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults”, Journal of Clinical Endocrinology & Metabolism, 2006 — https://pubmed.ncbi.nlm.nih.gov/16352683/
5. U.S. Food and Drug Administration, Drugs@FDA application overview for EGRIFTA (tesamorelin acetate), approved 10 November 2010 — https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=022505
6. DailyMed, EGRIFTA WR (tesamorelin) prescribing information — indication and Limitations of Use — https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75
7. Stanley TL et al., “Reduction in visceral adiposity is associated with an improved metabolic profile in HIV-infected patients receiving tesamorelin”, Clinical Infectious Diseases, 2012 — https://pmc.ncbi.nlm.nih.gov/articles/PMC3348954/
8. Sivakumar T et al., “Growth hormone axis treatments for HIV-associated lipodystrophy: a systematic review of placebo-controlled trials”, HIV Medicine, 2011 — https://pubmed.ncbi.nlm.nih.gov/21265979/
9. Astrup A et al., “Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial”, The Lancet, 2008 — https://doi.org/10.1016/S0140-6736(08)61525-1

Educational and research purposes only — not medical advice. Peptide Corner does not recommend any vendor, source, or dose. Keep safe, keep skeptical.