Drives the weight loss
These blunt appetite by copying GLP-1, a gut hormone that signals fullness after eating. Retatrutide appears in newer versions of this stack.
FDA approved· Stacks / weight
Two drugs that do not interact. One question nobody answered.
People losing weight on semaglutide or tirzepatide, the drugs sold as Ozempic, Wegovy, Mounjaro and Zepbound, add a second compound to hold onto muscle. The muscle loss is real and measured. Whether the second compound stops it has never been tested.
the recomp stack · muscle preservation
+
Meant to hold onto muscle
Secretagogues, meaning compounds that prompt your own pituitary gland to release more growth hormone instead of supplying any.
Research only· Evidence ladder
Both halves have been studied. The join has not.
SemaglutideHuman trials
TirzepatideHuman trials
IpamorelinHuman trials
CJC-1295Human trials
The two togetherNo studies
· Figures
The measurements are not interchangeable.
| Value | Scope | What it measures | Source tier |
|---|---|---|---|
| 9.7% | Semaglutide | How much muscle was lost, as a share of what they started with | preprint |
| ~11% | Tirzepatide | How much muscle was lost, as a share of what they started with | preprint |
| 25-40% | Both | How much of the total weight lost was muscle instead of fat | preprint |
| ~25% | Typical adult | How much of the total weight lost was muscle | commercial |
· Trial callout
A tested target, not a tested stack.
14.6%vs30.2%
Share of total weight lost that was muscle instead of fat, in people given a drug blocking myostatin, the body's own brake on muscle growth, against people given a dummy injection. Total weight lost was the same in both groups.
· What holds muscle
Tested options and mechanism-only claims are different things.
Human randomised evidence
Tested in people
- Resistance training during weight loss
- Adequate protein intake during weight loss
- Myostatin inhibition, one phase 2 trial, drug not available to consumers
Mechanism only
Plausible, never tested here
- Ipamorelin alongside a GLP-1
- CJC-1295 alongside a GLP-1
- Any secretagogue adding benefit on top of training and protein
· Current cost
Built from live in-stock listings.
Build it yourself$70.55/ 9 mg
Semaglutide$29.00 / 5 mg
Ipamorelin$17.56 / 2 mg
CJC-1295 no DAC (Mod GRF 1-29)$23.99 / 2 mg
Buy premixedNot sold
· Sources
Every reference says how it was read.
- 01Apitegromab for lean mass preservation during tirzepatide-induced weight loss: a randomized, double-blind, placebo-controlled phase 2 trial. Nature Medicine. DOI 10.1038/s41591-026-04440-4Primary paper and Table 2 read. The 14.6% and 30.2% figures are the share of total weight loss due to lean mass loss at week 24.Trial
- 02Impact of Semaglutide on Body Composition in Adults With Overweight or Obesity: Exploratory Analysis of the STEP 1 Study. Journal of the Endocrine Society. DOI 10.1210/jendso/bvab048.030Primary STEP 1 DXA substudy read. Lean body mass decreased 9.7% from baseline at week 68.Trial analysis
- 03Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes, Obesity and Metabolism. DOI 10.1111/dom.16275Primary SURMOUNT-1 DXA substudy read. Lean mass decreased 10.9% and accounted for about 25% of total weight lost.Trial analysis
- 04Effect of a high protein diet and/or resistance exercise on the preservation of fat-free mass during weight loss in overweight and obese older adults: a randomized controlled trial. Nutrition Journal. DOI 10.1186/s12937-017-0229-6Primary randomized trial read. The combination of resistance exercise and a high-protein diet best preserved fat-free mass during diet-induced weight loss.Trial
- 05Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. Diabetes, Obesity and Metabolism. DOI 10.1111/dom.15728Peer-reviewed review read. The 25% to 40% range is a synthesis across studies, not one trial result.Review
- 06TrimRX, ipamorelin stacking with GLP-1 medicationsCommercial page read. The typical-adult figure is a seller claim, not a clinical-trial result.Commercial
- 07Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. American Journal of Clinical Nutrition. DOI 10.3945/ajcn.115.119339Primary randomized trial read. This tested diet-induced weight loss with exercise, not weight loss caused by a GLP-1 medicine.Trial
- 08Peptide Decoding vendor pricing dataCurrent in-stock listings computed when the page loads.Own data