Retatrutide and tesamorelin are searched together because both come up in discussions of body fat, though they work in unrelated ways. Retatrutide is an investigational triple agonist of the GLP-1, GIP and glucagon receptors. Tesamorelin is an analog of growth hormone-releasing hormone (GHRH), FDA-approved as Egrifta for HIV-associated lipodystrophy.
At a glance
| Retatrutide | Tesamorelin | |
|---|---|---|
| What it is | Investigational triple GLP-1/GIP/glucagon receptor agonist studied in clinical trials for weight loss | Stabilized GHRH analog, FDA-approved as Egrifta for visceral fat in HIV-associated lipodystrophy |
| How it's thought to work | Activates GLP-1, GIP, and glucagon receptors together, studied for appetite suppression, insulin signaling, and energy expenditure | Stimulates pulsatile GH release, raising IGF-1 and preferentially mobilizing visceral abdominal fat |
| Regulatory status | Not FDA-approved; investigational, sold outside trials only by unregulated research-chemical suppliers | FDA-approved for HIV-associated lipodystrophy specifically; other uses are off-label |
| Strength of evidence | Human trials: a Phase 2 study (Jastreboff et al., NEJM 2023); not yet approved | Multiple human clinical trials support visceral fat reduction; basis for FDA approval |
| Reported side effects | Nausea (most common), diarrhea, vomiting, constipation, decreased appetite; generally mild to moderate | Injection site reactions, joint pain, fluid retention, tingling, elevated blood sugar |
| Common vial sizes | 5mg, 10mg | 2mg, 5mg, 10mg |
| Mixing math example | 5 mg + 1 mL BAC water = 5,000 mcg/mL, 50 mcg per unit | 5 mg + 2 mL BAC water = 2,500 mcg/mL, 25 mcg per unit |
Key differences
Retatrutide activates GLP-1, GIP and glucagon receptors and is studied for appetite suppression, insulin signaling and energy expenditure. Tesamorelin stimulates the body's own pulsatile growth hormone release, raising IGF-1, and research describes it as preferentially mobilizing visceral abdominal fat.
Tesamorelin is FDA-approved for HIV-associated lipodystrophy, and other uses are off-label. Retatrutide is investigational and not FDA-approved.
Retatrutide's most commonly reported side effect is nausea, along with diarrhea, vomiting, constipation and decreased appetite. Tesamorelin's include injection site reactions, joint pain, fluid retention, tingling and elevated blood sugar.
What the research covers
Retatrutide's main published human evidence is a Phase 2 trial in the New England Journal of Medicine (Jastreboff et al., 2023), with a substudy on liver fat. Tesamorelin's evidence is multiple human clinical trials of visceral fat reduction in HIV-associated lipodystrophy, the basis of its FDA approval.
Sources
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. Jastreboff AM et al. N Engl J Med, 2023. Human trial
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Sanyal AJ et al. Nature Medicine, 2024. Human trial
- Retatrutide: a triple incretin receptor agonist for obesity management. Ray A et al. Expert Opinion on Investigational Drugs, 2023. Review
- Metabolic effects of a growth hormone-releasing factor in patients with HIV. Falutz J et al. N Engl J Med, 2007. Human trial
- EGRIFTA (tesamorelin for injection), for subcutaneous use - Prescribing Information. U.S. Food and Drug Administration, 2019. Fda label
Frequently asked questions
What is the difference between retatrutide and tesamorelin?
Retatrutide is an investigational triple GLP-1, GIP and glucagon receptor agonist. Tesamorelin is a GHRH analog that raises growth hormone release and is FDA-approved as Egrifta.
Is retatrutide or tesamorelin FDA-approved?
Tesamorelin is FDA-approved for HIV-associated lipodystrophy only. Retatrutide is not FDA-approved.
Are retatrutide and tesamorelin the same type of drug?
No. Retatrutide acts on incretin and glucagon receptors, while tesamorelin acts on the GHRH receptor to raise growth hormone.
Which has more human research, retatrutide or tesamorelin?
Tesamorelin has multiple human trials and an FDA approval for one indication. Retatrutide's main published human evidence is a Phase 2 trial.
Both entries, plus the calculator
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