Which claims earn confidence?
The most optimistic conclusion changes with the question. Cardiovascular events, weight, fat location and mouse biology each have their own record.
A comparison of the strongest claims
I can be bullish about a finding without giving the whole molecule a favourable verdict. The following entries say what earns confidence and which extension would need more work. They are questions for the literature, rather than a treatment ranking.
| Compound | Claim supported here | Question left open |
|---|---|---|
| Semaglutide | Fewer combined cardiovascular events in SELECT, in adults with established cardiovascular disease and excess weight, without diabetes | How broadly does that benefit extend beyond the people enrolled? |
| Tirzepatide | Greater mean weight loss than semaglutide in SURMOUNT-5, in adults with obesity without type 2 diabetes | How do other health outcomes and tolerability compare? |
| Tesamorelin | Reduced visceral and liver fat in adults with HIV-associated abdominal fat accumulation | What persists after treatment ends, and how does the evidence translate beyond HIV? |
| MOTS-c | Improved glucose handling and protection from diet-induced obesity in mice | Does giving MOTS-c to people produce a useful, acceptably safe effect? |
Weight comparisons
SURMOUNT-5 makes the direct comparison: -20.2% mean body-weight change with tirzepatide and -13.7% with semaglutide at 72 weeks in 751 adults with obesity without type 2 diabetes. The same trial compared both treatments. STEP 1’s semaglutide result and SURMOUNT-1’s tirzepatide results came from separate trials; stacking those percentages would introduce differences in participants and design.
For weight, the experiment that compared the treatments directly gets my backing. Neither a larger weight reduction nor the word “peptide” answers every cardiovascular, kidney or muscle-function question.
Duration and fat location
Tesamorelin’s 52-week findings include both sustained visceral-fat reduction during treatment and reaccumulation after stopping. That makes the time after treatment a central part of its case. Its scan-area measurements also concern a different outcome from total body weight.
A pooled increase in lean body mass with tesamorelin cannot be read as stronger muscles: water and organs count towards that measure. With large weight loss, lean-tissue loss raises a different concern. Function deserves to be measured directly.
Tolerability
Semaglutide’s safety review describes common gastrointestinal effects and increased biliary disease. The tirzepatide meta-analysis found increased combined gallbladder or biliary disease while leaving an increased pancreatitis risk unconfirmed. These are meaningful limits alongside meaningful benefits.
MOTS-c has a more basic gap: these papers establish no human treatment safety. Tesamorelin’s approved HIV-associated use comes with growth-hormone and IGF-1 concerns. An optimistic comparison needs space for known harms and missing measurements alike. My judgement would change with stronger human outcomes, longer follow-up and clearer evidence about physical function.