If you are weighing semaglutide, tirzepatide, retatrutide or a peptide sold online as a fat burner, the line is clear. The GLP-1 family has trials in thousands of people. Nearly everything else has mouse data or a failed trial. This page puts the numbers side by side.
New trials, FDA changes and side-effect reports, written in plain English. Every result says whether it was tested in people or in animals.
Each bar is the average percentage of body weight lost at the end of a randomized, placebo-controlled trial. Switch to the placebo-adjusted view to see how much of the loss the drug itself caused.
Mean % of body weight lost on the drug
Retatrutide in TRIUMPH-1
2,339 adults with obesity or overweight and no diabetes, 80 weeks. Highest dose arm: 25.0% lost on average, against 3.9% lost on placebo. Placebo-adjusted difference: 21.1 points.
In clinical trials
Trials ran for different lengths (48 to 80 weeks) and enrolled different people, so bars are not a head-to-head ranking. Only two trials compared drugs directly: tirzepatide beat semaglutide 20.2% to 13.7% (SURMOUNT-5), and tirzepatide beat CagriSema 25.5% to 23.0% (REDEFINE 4). Tap a bar for the trial details.
The 24-week OPTIONS trial enrolled 536 adults with obesity and randomized 502 of them. Weight loss against placebo was too small to reach statistical significance, the company ended the program in February 2007, and the full results never appeared in a journal. FDA briefing document
These drugs copy gut hormones that tell the brain you have eaten. Each new class adds a receptor. Pick a class to see the receptors it acts on, the organs those receptors reach, and its best trial result.
The largest average weight loss of any drug in a published phase 3 trial. Not approved; no heart-outcome data yet.
Drugs in this classRetatrutide
Pulled live from the peptide database and sorted by evidence grade, then by how many human studies exist. The bar splits each compound's key studies into those done in people and those done in animals or cells.
Every compound studied for fat loss in this database
Two results that change how to read every number above. Both come from the same randomized trials.
Change in body weight over the following year, from the day of the switch
Bars grow left for further loss and right for regain. Center line is the weight on the day of the switch.
Share of total weight lost that was fat versus lean mass, measured by DEXA scan in a subgroup of each trial
Lean mass on a DEXA scan includes muscle, organs and water, so it is not the same as muscle alone. Losing some lean mass happens with any large weight loss, including from dieting. The trials measured it by scan; they did not test whether it changed strength.
What the muscle peptides actually showedMain obesity trial in adults without diabetes for each drug. US status comes from the database and changes as approvals land.
"On-drug analysis" counts only people who kept taking the drug, which makes the number look larger than an analysis of everyone randomized. Orforglipron is a small-molecule pill, not a peptide, and has no profile in the peptide database.
Survodutide and retatrutide have never been tested in the same trial. Their separate weight, liver and side-effect results are compared in survodutide vs retatrutide.
Mazdutide and tirzepatide have not been tested in the same trial either. Their results in Chinese adults are set side by side in mazdutide vs tirzepatide.
These are the fat-loss compounds sold without a prescription as research chemicals. None is approved for anything. Here is the best evidence for each.
Grade B for AOD-9604 and HGH fragment 176-191 means randomized human trials exist. It does not mean the trials worked.
Questions that come up constantly and that no published trial has answered.
The longest placebo-controlled weight data run about 3 years (the SURMOUNT-1 extension, 176 weeks). Nobody has data on 20 years of continuous use. Source
No trial has reported heart attacks, strokes or deaths on retatrutide, and no trial has run past about 2 years. Source
No trial tested compounded semaglutide salt forms or vials sold "for research use only". FDA says salt forms such as semaglutide sodium are not the same active ingredient as the approved drug. Source
No published trial has combined a GLP-1 drug with BPC-157, MOTS-c, AOD-9604 or any other research peptide.
No compound on this page has been shown in a published trial to protect muscle during GLP-1 weight loss. The trials measured lean mass by DEXA, not strength. Source
Not one of the research compounds sold for fat loss has a positive, published human trial. The best result for any of them is in mice. Source
The doses used in each trial on this page, with route, schedule and source, are on every drug's profile for free members.
Create a free accountRetatrutide, CagriSema and eloralintide all have results and FDA decisions coming. One email when a trial reads out or a label changes, with the numbers checked against the source.