Retatrutide vs semaglutide · research comparison
Retatrutide vs semaglutide: three receptors against one.
The cleanest way to understand retatrutide is against semaglutide — the difference is the number of receptor systems each engages. Semaglutide is a single GLP-1 receptor agonist; retatrutide (LY3437943) is a triple agonist that engages GLP-1, GIP, and glucagon receptors at once. This page compares the two as research compounds: mechanism, the published trial figures, and half-life — not as medicines or dosing advice.
The mechanism difference
Semaglutide is a selective GLP-1 receptor agonist — it engages one incretin pathway. Retatrutide is a triple agonist of GLP-1, GIP, and the glucagon receptor (GCGR). The glucagon-receptor component is the defining differentiator in the literature: it is discussed as adding hepatic energy-expenditure and lipid-oxidation signalling that single-pathway GLP-1 compounds do not directly engage.
The GLP-1 research class →The published trial figures
In the NEJM 2023 Phase 2 retatrutide trial (Jastreboff et al., n=338), the 12mg weekly arm reached a mean −24.2% body weight at 48 weeks — the largest figure reported for a single anti-obesity compound in trials at that time. Semaglutide's published weight-loss figures in obesity trials are in the ~15–16% range over 68 weeks. These are clinical-trial endpoints reported in the literature, cited here for research context only.
Retatrutide vs tirzepatide →Structure and half-life
Both carry fatty-acid modifications that extend plasma half-life to support once-weekly dosing in study models — retatrutide ~6 days, semaglutide ~7 days. Retatrutide is a 39-residue synthetic peptide (CAS 2381089-83-2) with non-natural amino-acid substitutions; semaglutide is a 31-residue GLP-1 analogue. Both are supplied as lyophilized powder for reconstitution before in-vitro use.
Reconstitution & shelf life →What Aurora stocks
Aurora stocks retatrutide as a 10mg lyophilized vial ($199.99) with a lot-matched release sheet, an HPLC purity target, and mass-spec identity confirmation. Semaglutide is the comparison reference in this article; for the GLP-1 research class, retatrutide is the in-stock triple-agonist tool. Confirm format and documentation on the product page before ordering.
Where to buy retatrutide →How to source it
Aurora is crypto-only — BTC, USDC, or SOL. The network and wallet are shown before payment and an order ID is logged with support first. Paying in USDC holds the total at the quoted figure. The screen on a research-reagent comparison should always point to documented material, not just a price.
Crypto checkout walkthrough →Where the research-use line sits
Retatrutide is an investigational compound in Phase 3 trials; semaglutide is FDA-approved as a medicine but is referenced here only as a research comparator. Nothing here is dosing guidance or a human-use protocol — research-grade material in either case is supplied strictly for in-vitro laboratory work and is not for human use.
See the testing workflow →The detail, in plain terms
Single agonist vs triple agonist, side by side.
The comparison rests on pharmacology, not engineering — both use fatty-acid half-life extension; the difference is one receptor target versus three. Figures below are published clinical-trial endpoints cited for research context only.
- Semaglutide
- Single GLP-1 receptor agonist · 31 residues · ~7-day half-life.
- Retatrutide
- Triple GLP-1 + GIP + glucagon agonist · 39 residues · ~6-day half-life.
- Key differentiator
- Retatrutide's glucagon-receptor (GCGR) engagement — energy-expenditure signalling.
- Trial weight loss
- Retatrutide −24.2% (48 wks, Phase 2); semaglutide ~15–16% (68 wks).
- Regulatory status
- Semaglutide approved; retatrutide investigational (Phase 3).
- Aurora stocks
- Retatrutide 10mg lyophilized, $199.99 — research use only.
Questions researchers ask
Before you order.
- What is the difference between retatrutide and semaglutide?
- Semaglutide is a single GLP-1 receptor agonist; retatrutide (LY3437943) is a triple agonist engaging GLP-1, GIP, and the glucagon receptor at once. The glucagon-receptor component is the defining difference in the literature, discussed as adding hepatic energy-expenditure and lipid-oxidation signalling that single-pathway GLP-1 compounds do not directly engage. Both are research compounds here, not medical advice.
- Which showed more weight loss in trials?
- In published clinical trials, retatrutide's Phase 2 (NEJM 2023) 12mg arm reached a mean −24.2% body weight at 48 weeks, versus semaglutide's roughly 15–16% over 68 weeks in obesity trials. These are trial endpoints cited for research context only — not a claim about any product Aurora sells and not human-use guidance.
- Do retatrutide and semaglutide have similar half-lives?
- Both use fatty-acid modifications that extend plasma half-life to support once-weekly dosing in study models — retatrutide approximately 6 days and semaglutide approximately 7 days. Both are supplied as lyophilized powder for reconstitution before in-vitro use.
- Does Aurora sell both retatrutide and semaglutide?
- Aurora stocks retatrutide as a 10mg lyophilized vial at $199.99. Semaglutide is referenced in this comparison as the single-agonist research comparator. For the GLP-1 research class, retatrutide is Aurora's in-stock triple-agonist tool, supplied with a lot-matched release sheet and HPLC purity target.
- Are these compounds approved for human use?
- Research-grade retatrutide and semaglutide sold as reagents are not for human use. Retatrutide is additionally an investigational compound. Aurora supplies research material strictly for in-vitro laboratory work — not for human or animal consumption, and not for diagnostic, therapeutic, or preventative use.