DIFFERENT PATIENTS, DIFFERENT TESTS
Which findings answer your question about daily strength?
Getting up from a chair can stay hard even after weight falls. These compounds were tested in different ways. You can't choose a strength winner from weight alone.
Why is there no clear winner for stronger legs?
Walking more easily and weighing less are different changes in your day. The tesamorelin patients had problems with fat storage associated with HIV. Scans showed that fat surrounding organs fell while weight apart from fat rose [1]. MOTS-c improved grip, walking, and running in mice [11]. Large human trials found weight and other health changes with tirzepatide and semaglutide [13][16][18][19][20]. Those findings don't establish stronger grip or better walking for those patients.
I'd start with who was tested, then what the test showed.
A scan estimates tissue amounts; a movement test checks ability. Cells, mice, and patients also give different kinds of answers. You need both details before relating the finding to your own legs. A large trial about illness can leave your strength question unanswered. A mouse test of grip can be direct without proving any human benefit. None gives a fair strength ranking across these four compounds.
What was tested for each of the four compounds?
| Compound | What does it do? | Who took part? | What happened to weight or tissue? | What about movement? | What don't we know? |
|---|---|---|---|---|---|
| Tesamorelin | Prompts the release of hormones involved in growth. | Adults whose HIV caused unusual fat storage were assigned to groups by chance [1][3][5][6]. | Less fat around organs, in the trunk and liver; more weight apart from fat [1]. | Those scans don't prove better strength. | Whether the tissue change made daily tasks easier. |
| MOTS-c | Changes how cells use fuel. | Cells and animals received treatment; kidney patients were followed without treatment [8][9][11][12]. | Mice had less muscle shrinkage and changed fuel use [8]. | Mice improved in grip, walking, and running tests [11]. | Whether treatment benefits people, and how often harm occurs. |
| Tirzepatide | Copies meal-related messages from GIP and GLP-1 to lower hunger and high blood sugar. | Adults with obesity or diabetes took part in large trials [13][16][17]. | Weight fell; loss of tissue apart from fat remains a concern. | Weight findings don't establish better strength. | Whether people kept strength while losing weight. |
| Semaglutide | Copies GLP-1 messages involved in appetite and blood-sugar control. | Large trials examined kidney health and heart problems as well as weight [18][19][20]. | Weight fell; loss of tissue apart from fat remains a concern. | Those findings don't prove easier walking. | What tissue changes meant for daily strength, especially in frail patients. |
Which test matches the change you want to understand?
Scales measure your total weight, while scans estimate fat and other tissue. Blood tests can check sugar, fats, or hormones. Grip tests measure strength, and walking tests show how well people move. A timed test of getting up checks another daily ability. You can't use the answer from one test as the answer to all the others.
With tesamorelin, scans showed reductions in both liver fat and fat surrounding organs. Weight apart from fat increased too [1][3]. MOTS-c movement tests involved animals [8][11]. Tirzepatide and semaglutide trials found changes in weight, blood sugar, or serious illness [13][17][18][19][20].
A benefit can be real while another question stays open.
Ask whether your concern was actually tested. If keeping a steady walk matters most, a lower blood-sugar reading won't answer that question. You can value both results while keeping their meanings clear.
How much does your health resemble the patients' health?
A treatment result depends in part on the patients who took part. Most tesamorelin patients had unusual fat storage associated with HIV [1][3][5][6]. You can't assume those findings apply to everyone wanting weight loss. MOTS-c treatment tests involved cells and mice. Its human study followed natural MOTS-c levels in patients needing blood cleaning for failing kidneys [9].
Ask if the patients shared the health concern you brought to the visit.
Tirzepatide and semaglutide trials involved adults with particular health problems. The groups included obesity, type 2 diabetes, kidney disease, or disease in the heart or blood vessels [13][16][17][18][19][20]. They don't all represent the same patients or the same treatment goal.
Better mouse grip doesn't prove better grip in you. Adults with HIV losing fat doesn't establish a bodybuilding benefit. Fewer heart problems don't show that patients had stronger muscles. The study needs to match both your health question and the ability you care about.
Can a strong finding still miss what matters to you?
MOTS-c movement tests involved animals, while its human study didn't test treatment [9][11]. Semaglutide has large human trials about serious illness that don't settle strength [18][19]. Tesamorelin has human scan findings without matching direct movement tests [1]. Tirzepatide has strong human weight results, but daily strength still needs checking [13][16].
A well-tested benefit doesn't answer every question you bring.
Be wary of a claim that joins a mouse strength result to an unrelated patient trial. The patient trial can't turn that mouse result into a human benefit. Ask which study directly supports the proposed strength claim. Which treatment did people receive, and what did researchers test afterward? You can't tell what the claim means for your legs unless the answer identifies who took part, what they received, and which test followed. Missing that link leaves the benefit unproved for you.
What would researchers need to check next?
A useful strength study would repeat scans of fat and other tissue in arms and legs, alongside tests of grip, walking speed, and chair standing in the same people. Checking how long people could keep moving would give you another useful answer. You'd want results for different ages, illnesses, and starting strength, as well as different speeds of weight loss.
Until then, the trials don't give you a fair strength winner.
Adults with HIV had fat-storage changes and more weight apart from fat with tesamorelin [1]. MOTS-c improved movement tests in mice [11]. Tirzepatide and semaglutide changed weight and other health results in particular patient groups [13][16][18][19][20]. Those findings are useful without promising easier movement. At a visit, ask which finding applies to your goal, and which question still needs testing. That gives you a clearer answer than choosing by weight loss alone.