Retatrutide vs NA-931
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: LY3437943, Triple G
Retatrutide is the heavy hitter of the new weight-loss drugs: a once-weekly injectable peptide that hits three receptors at once - GIP, GLP-1, and glucagon - earning it the nickname triple-G agonist. In a phase 2 trial it produced some of the largest weight loss ever recorded for a drug, up to roughly 24 percent of body weight at the top dose. It is investigational, made by Eli Lilly, and not yet FDA approved as of 2026.
Also: Bioglutide, cyclic glycine-proline
NA-931 (Bioglutide) is cyclic glycine-proline, a two-amino-acid ring that occurs naturally as a breakdown product of IGF-1. Its developer, Biomed Industries, describes it as an oral once-daily agonist at four receptors at once - IGF-1, GLP-1, GIP and glucagon - and has reported 13 to 15 percent weight loss in a 126-person Phase 2 trial. Those numbers have only ever appeared in conference abstracts, never in a peer-reviewed paper, and no trial results have been filed to ClinicalTrials.gov. The same molecule is already sold as a consumer brain-health supplement and as a Sigma-Aldrich catalogue chemical, which makes it unusually cheap to source and unusually hard to verify.
Key Comparison Insights
- Both peptides belong to the Weight Loss category, suggesting similar primary applications.
Detailed Comparison
| Attribute | Retatrutide | NA-931 |
|---|---|---|
| Category | Weight Loss | Weight Loss |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Retatrutide combines three hormone signals into one molecule. The GLP-1 component curbs appetite and slows stomach emptying, the GIP component supports insulin response and may improve how fat tissue handles nutrients, and the added glucagon receptor activity is the novel piece: glucagon can increase energy expenditure and fat burning in the liver. The idea is that two arms cut how much you eat while the third raises how much you burn, which is why retatrutide is thought to push weight loss further than GLP-1-only drugs like semaglutide or even the dual GIP/GLP-1 agonist tirzepatide. The exact contribution of each receptor in humans is still being worked out, so consider the glucagon-driven energy-expenditure story a strong hypothesis rather than fully nailed down. | Cyclic glycine-proline is a diketopiperazine: glycine and proline joined into a small ring, 154 daltons, roughly a thirtieth the size of tirzepatide or retatrutide. The independent literature, mostly from Jian Guan's group in Auckland, describes a single mechanism: cGP competes with IGF-1 for binding to IGFBP-3, which frees up IGF-1 that was otherwise bound and inactive. That is a bioavailability effect, studied for stroke recovery, Parkinson's and blood pressure rather than for weight. Biomed's own patent filing (WO2025160184A1) goes much further, claiming the same molecule is a 'quadruple receptor agonist' at IGF-1, GLP-1, GIP and glucagon receptors. That claim is worth understanding properly, because it is the entire basis of the weight-loss story. GLP-1, GIP and glucagon receptors are class B GPCRs, the kind that normally need a thirty-plus residue peptide wrapping into the receptor's binding groove to switch on. A 154-dalton ring activating all three would be a genuinely significant pharmacological finding. No independent group has reported it. Searching PubMed for cyclic glycine-proline alongside GLP-1 returns nothing at all. |
| Common Dosing | 4-12 mg weekly Once weekly, same day each week | 120 mg daily, oral Once daily |
| Administration | Subcutaneous injection weekly | Oral capsule or tablet, once daily |
| Typical Duration | Long-term use expected | 28 days in Phase 1, 13 weeks in Phase 2 |
| Best Time to Take | Morning, same day each week | Consistent daily timing |
Possible Side Effects May vary by individual |
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| Research Summary | The key human evidence is the phase 2 trial by Jastreboff and colleagues, published in the New England Journal of Medicine in 2023, which randomized 338 adults with obesity (without type 2 diabetes) over 48 weeks. Mean weight reduction reached about 24 percent at the 12 mg dose, and weight loss had not clearly plateaued by week 48, hinting the ceiling could be even higher. Among participants with prediabetes at baseline, a large majority returned to normal blood sugar. Side effects were dominated by gastrointestinal issues like nausea, vomiting, and diarrhea, the familiar pattern for this drug class, and were mostly dose-dependent. These are genuinely strong phase 2 results, but they are phase 2: larger and longer phase 3 trials are underway to confirm safety and durability, and retatrutide sold outside of trials is not an approved, quality-controlled medicine. | There are no peer-reviewed publications on NA-931. Not one. Everything in circulation is a conference abstract, and the abstracts carrying the efficacy numbers list Biomed's CEO as sole author with conflicts declared as 'None'. Two trials have completed, both run entirely in Australia: a 74-person Phase 1 (NCT06615700, completed September 2024) and a 126-person Phase 2 (NCT06564753, completed April 2025). Neither has results posted. A third trial (NCT06732245) would run in the US, Australia and New Zealand, but has not started recruiting. The reported weight loss is where this gets difficult. The same 126-person Phase 2 has been presented three times with three different numbers: 14.8 percent at ADA in June 2025, 13.8 percent at ENDO in July, and 13.8 percent with a different placebo-adjusted figure in a September press release. Enrolment is given as 125 in the abstracts against 126 on the registry. A result that moves between presentations is not yet a result. The company's website states NA-931 is in Phase 3. No Phase 3 trial for NA-931 is registered on ClinicalTrials.gov. The announcement traces to a single paid newswire release in January 2026, syndicated into around twenty local newspaper press-release sections, which reads like broad coverage but is one purchased placement. |
Frequently Asked Questions: Retatrutide vs NA-931
What is the difference between Retatrutide and NA-931?
Retatrutide is a weight loss peptide that retatrutide is the heavy hitter of the new weight-loss drugs: a once-weekly injectable peptide that hits three receptors at once - gip, glp-1, and glucagon - earning it the nickname triple-g agonist. in a phase 2 trial it produced some of the largest weight loss ever recorded for a drug, up to roughly 24 percent of body weight at the top dose. it is investigational, made by eli lilly, and not yet fda approved as of 2026. NA-931 is a weight loss peptide that na-931 (bioglutide) is cyclic glycine-proline, a two-amino-acid ring that occurs naturally as a breakdown product of igf-1. its developer, biomed industries, describes it as an oral once-daily agonist at four receptors at once - igf-1, glp-1, gip and glucagon - and has reported 13 to 15 percent weight loss in a 126-person phase 2 trial. those numbers have only ever appeared in conference abstracts, never in a peer-reviewed paper, and no trial results have been filed to clinicaltrials.gov. the same molecule is already sold as a consumer brain-health supplement and as a sigma-aldrich catalogue chemical, which makes it unusually cheap to source and unusually hard to verify. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Retatrutide or NA-931?
Neither is universally "better" - the choice depends on your specific goals. Retatrutide is typically used for weight loss purposes, while NA-931 is used for weight loss. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Retatrutide and NA-931 be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Retatrutide and NA-931 together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.