Mazdutide

FDA status

Two claims, verified separately. NOT APPROVED BY FDA: the quoted finding is FDA's, made on 2026-03-31 about products offered for sale as 'Mazdutide' by a US website, and it is corroborated by seven Drugs@FDA queries returning NOT_FOUND on 2026-08-02. IN ACTIVE DEVELOPMENT: verified against the ClinicalTrials.gov API on 2026-08-02, which returned 36 registrations naming mazdutide, IBI362 or LY3305677. Two sponsors carry the programme. Eli Lilly and Company holds the US-registered trials — NCT06124807 (Phase 2, 179 participants, 29 US sites, COMPLETED 2025-07-09, results posted), NCT06817356 (Phase 2, alcohol use disorder, 308 participants, 25 US sites, COMPLETED 2026-05-19) and the CWMM master protocol NCT06143956, which is RECRUITING at 54 sites in the US and Argentina with LY3305677 listed among its interventions and estimated completion in 2028. Innovent Biologics (Suzhou) Co. Ltd. holds the Phase 3 programme, including registrations that began recruiting as recently as 2026-04-23 (NCT07469800). HONEST LIMITS, and they matter for how this label should be read. Every Phase 3 registration located for this record is conducted in China; the registered US trials are Phase 2. This record makes NO claim about whether an IND or a marketing application exists for mazdutide in the United States — INDs are not public, and Drugs@FDA lists applications, not investigations, so silence there is not evidence either way. What is recorded is what the registries and Drugs@FDA actually show. Being in trials is not evidence that a compound works, and it is not permission to buy one.

Evidence

ADMINISTRATION CHECK RUN, NOT ASSUMED. Mazdutide is a synthetic investigational peptide and not an endogenous human peptide, so the biomarker trap that empties MOTS-c's and TB-500's apparent trial counts cannot arise here — but the check was run per-study anyway. In GLORY-1 (NCT05607680, NEJM 2025) investigators randomly assigned 610 Chinese adults with obesity or overweight to receive mazdutide or placebo and reported mean percentage changes in body weight from baseline at week 32 of -10.09% and -12.55% in the two mazdutide groups versus +0.45% with placebo, with 73.9% and 82.0% of mazdutide participants versus 10.5% of placebo participants achieving a reduction of at least 5% (P<0.001 for all comparisons with placebo). In GLORY-2 (NCT06164873, JAMA 2026), a double-blind placebo-controlled Phase 3 trial at 27 hospitals running from December 2023 to November 2025, 461 Chinese adults with obesity received treatment and investigators reported a mean change in body weight at week 60 of -16.65% with mazdutide versus -1.50% with placebo. The ClinicalTrials.gov intervention records for both read as a DRUG administered subcutaneously, and both trials were funded by Innovent Biologics. Mazdutide has also been administered to humans in the United States: NCT06124807, an Eli Lilly Phase 2 obesity trial at 29 US sites, completed 2025-07-09 with results posted. WHAT THIS TIER DOES AND DOES NOT MEAN. It means efficacy on the endpoint those trials measured — body weight — is established by adequate, well-controlled human trials. It does NOT mean FDA-approved; FDA has made no safety-and-effectiveness finding on mazdutide, and has found products sold as mazdutide in the US to be unapproved new drugs. It does not mean the evidence generalises freely: every Phase 3 trial cited here enrolled Chinese adults in China, the trials were 48 to 60 weeks long, and no cardiovascular or kidney outcomes trial of mazdutide has reported. And it does not transfer to grey-market product — these findings describe Innovent's and Lilly's investigational material under trial conditions, not the contents of a vial bought online. Per-arm strengths are left to the cited papers deliberately.

What FDA found

FDA’s own words. These are the most citable thing on this site, and the least likely to appear anywhere funded by someone selling the compound.

• FDA found that products offered for sale as 'Mazdutide' by a US website are unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act, and that introducing or delivering them for introduction into interstate commerce violates sections 301(d) and 505(a).

  FDA naming mazdutide, in writing, as recently as March 2026. Read the scope precisely in both directions. This is a finding about a seller's products, not a pharmacological finding about the molecule, and it binds that firm — it is cited here as evidence of FDA's legal position on mazdutide sold this way, not as a claim about any other vendor. But it is also not a technicality: FDA states flatly that no approved section 505 applications are in effect for these products, which is the same thing seven Drugs@FDA queries showed independently. Note also the reconstitution-kit finding, which reaches further than most readers expect — FDA held that selling bacteriostatic water together with a syringe alongside peptide products 'demonstrates that you intend for the “BAC water” to be used in combination for injection. Therefore, your “BAC water” is a drug.'

  Warning Letter — Prime Sciences (MARCS-CMS 721805) — FDA, 31 March 2026

  “The FDA has observed that your website offers “Cagrilintide,” “GLP1-R,” “GLP1-S,” “GLP1-T,” “Mazdutide,” and “BAC water” … for sale in the United States. Based on our review, these products are unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 355(a).”

  Checked against the source on 2 August 2026.

• FDA held that labeling mazdutide and other peptide products for 'laboratory research purposes only' and 'not for human consumption, medical use or veterinary use' did not defeat evidence of intended use obtained from the seller's own website.

  The research-label theory, applied to mazdutide, and failing on the same reasoning FDA has used against it repeatedly elsewhere in this library. What makes this letter instructive is WHICH evidence FDA cited from the mazdutide product page: the seller's own invocation of the Chinese Phase 3 programme. FDA reproduced the claim 'Mazdutide peptide therapy benefits include: … Significant weight loss: In a phase 3 trial (GLORY-1), once-weekly mazdutide led to an average body weight reduction of up to 14.8%' as evidence that the product was intended as a drug for human use. That is the laundering mechanism this record exists to interrupt: a real, published, peer-reviewed trial of a sponsor's investigational material, quoted on a webpage to sell an unverified vial, and treated by FDA as the exhibit rather than the defence.

  Warning Letter — Prime Sciences (MARCS-CMS 721805) — FDA, 31 March 2026

  “Despite statements on your product labeling marketing your products for “laboratory research purposes only” and “not for human consumption, medical use or veterinary use,” evidence obtained from your website establishes that your products are intended to be drugs for human use.”

  Checked against the source on 2 August 2026.

• In an earlier warning letter, FDA found products offered as 'Mazdutide' alongside semaglutide, retatrutide, cagrilintide and tirzepatide to be unapproved new drugs introduced into interstate commerce in violation of sections 505(a) and 301(d), notwithstanding labeling marketing them as 'RESEARCH USE ONLY'.

  Recorded because two letters fifteen months apart establish a standing FDA position rather than a one-off 2026 action. The specific claim FDA cited from this seller's mazdutide page is worth reading against the site's own house style: 'Mazdutide is an investigational peptide with a novel dual-action mechanism … has shown promising results in early studies related to weight management and glucose regulation.' Every word of that is hedged, and FDA still treated it as evidence of intended use. The research-chemical framing does not survive contact with a webpage describing what the product does for a person.

  Warning Letter — Summit Research Peptides (MARCS-CMS 695607) — FDA, 10 December 2024

  “Despite statements on your product labeling marketing your products as “RESEARCH USE ONLY” and “INTENDED AS A RESEARCH CHEMICAL ONLY,” evidence obtained from your websites establish that your products are intended to be drugs for human use.”

  Checked against the source on 2 August 2026.

• Mazdutide appears in none of Categories 1, 2 or 3 of FDA's list of bulk drug substances nominated for use in compounding under section 503A, updated 2026-05-14.

  Verified on 2026-08-02 by downloading the PDF with a browser user-agent and extracting its text locally: the string 'mazdutide' does not occur anywhere in the document, while control strings that should be present — Cesium Chloride, Ibutamoren, Kisspeptin — all are, which is what makes the absence a finding rather than a failed extraction. Recorded to close a misreading, not to assert a status, and this record deliberately carries no 503A status field as a result. Mazdutide's absence means the same thing semaglutide's does and something entirely different from BPC-157's: BPC-157 was nominated and left Category 2 when the nominators withdrew, whereas mazdutide was never in this system at all. Categorical silence is neither permission nor a safety finding.

  Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act — FDA, 14 May 2026Checked against the source on 2 August 2026.

• Mazdutide (Xinermei) received its first regulatory approval anywhere in China in June 2025, from China's National Medical Products Administration, for long-term body weight management in adults, and a second Chinese approval in September 2025 for glycaemic control in adults with type 2 diabetes. Neither is an FDA approval and neither has any legal effect in the United States.

  Filed under FDA findings for a structural reason: this is the single fact most likely to be misread as an FDA approval, so it sits where the reader is already looking at what FDA has and has not done. It is NOT recorded in this record's fdaApproval field, which is reserved for FDA approvals and renders as one. Read the approved Chinese indication precisely, because it is narrower than the marketing: the weight-management approval is 'in combination with diet control and increased physical activity' and is gated on stated BMI thresholds, one of which additionally requires a weight-related comorbidity. SOURCING LIMIT, stated plainly: NMPA does not publish an English-language approval document at a stable citable URL, so this is carried by a peer-reviewed Adis drug-development review rather than by the regulator's own document — a weaker link than every FDA citation on this record, and recorded as such rather than dressed up. The sponsor's own press releases report the same two approvals and the same dates.

  Mazdutide: First Approval — Drugs, 30 September 2025

  “In June 2025, mazdutide received its first approval, in China, for use (in combination with diet control and increased physical activity) in long-term body weight management in adults with a body-mass index (BMI) of ≥ 28 kg/m2 or with a BMI ≥ 24 kg/m2 together with one or more weight-related comorbidity. Subsequently, in September 2025, mazdutide also received approval in China for use in glycaemic control in adults with T2D.”

  Checked against the source on 2 August 2026.

Documented safety signals

• In the Phase 3 GLORY-2 trial, investigators reported that the most common adverse events in the mazdutide group were vomiting (53.1%, versus 1.3% with placebo), nausea (46.9% versus 3.2%) and diarrhea (39.4% versus 6.5%), that most adverse events were mild to moderate in severity, and that adverse events leading to study treatment discontinuation occurred in 2.9% of the mazdutide group versus 0% of the placebo group.

  Attributed to the trial and scoped to it. Recorded prominently because 'well tolerated' is doing heavy lifting in how this compound is marketed, and the trial's own numbers do not read that way: more than half the participants receiving mazdutide vomited. The trial's authors put it in the conclusion themselves — participants receiving the drug 'experienced gastrointestinal adverse reactions compared with those receiving placebo'. Two limits bound this. These rates come from a monitored trial in which the strength was assigned and escalation supervised, a condition that does not exist outside a trial. And 461 participants over 60 weeks cannot characterise uncommon or long-latency harms.

  Treatment With 9-mg Mazdutide for Weight Reduction in Chinese Adults With Obesity: The GLORY-2 Randomized Clinical Trial — JAMA, 7 June 2026

  “Adverse events leading to study treatment discontinuation were reported in 2.9% of participants in the mazdutide group compared with 0% in the placebo group. The most common adverse events were vomiting (53.1% in the mazdutide group vs 1.3% in the placebo group), nausea (46.9% vs 3.2%, respectively), and diarrhea (39.4% vs 6.5%); most of the adverse events were mild to moderate in severity.”

  Checked against the source on 2 August 2026.

• In the Phase 3 GLORY-1 trial, investigators reported that the most frequently reported adverse events were gastrointestinal and mostly mild to moderate in severity, and that adverse events leading to discontinuation of the trial regimen occurred in 1.5% and 0.5% of the two mazdutide groups versus 1.0% of the placebo group.

  Recorded beside GLORY-2 rather than in place of it, because the two trials characterise tolerability very differently and a reader shown only one would be misled. GLORY-1 reports discontinuation rates at or below placebo; GLORY-2 reports vomiting in a majority of participants. The trials are not directly comparable — different strengths, different entry BMI, 48 weeks against 60 — and this record does not adjudicate between them. The per-group strengths behind the two discontinuation figures are elided under this site's no-dosing policy; no finding depends on them.

  Once-Weekly Mazdutide in Chinese Adults with Obesity or Overweight — The New England Journal of Medicine, 12 June 2025

  “The most frequently reported adverse events were gastrointestinal and mostly mild to moderate in severity.”

  Checked against the source on 2 August 2026.

• FDA has stated that products such as those sold as 'Mazdutide' are especially concerning from a public health perspective because injectable drug products can pose risks of serious harm to users, being delivered directly into the body and bypassing some of the body's key defenses against toxins and microorganisms.

  The signal that applies to the way people actually obtain mazdutide in the United States. It is a finding about the dosage form and the supply, not about the molecule: the published trials cannot speak to it either way, because those trials used the sponsors' investigational material rather than a vial bought from a website. WHAT IS NOT CLAIMED HERE: this record found no FDA adverse-event count, import alert or counterfeit finding naming mazdutide specifically, and none is asserted. FDA publishes such figures for compounded semaglutide and tirzepatide; it has not published a comparable figure for mazdutide, and importing one would attribute to this compound what FDA wrote about others.

  Warning Letter — Prime Sciences (MARCS-CMS 721805) — FDA, 31 March 2026

  “These products are especially concerning from a public health perspective because injectable drug products can pose risks of serious harm to users. Injectable products are delivered directly into the body, sometimes directly into the bloodstream, and therefore, bypass some of the body's key defenses against toxins and microorganisms that can lead to serious and life-threatening conditions.”

  Checked against the source on 2 August 2026.

Questions people actually ask

Every answer cites the document behind it. Where the honest answer is “nobody knows”, that is the answer you will get.

Is mazdutide FDA-approved?

No. Mazdutide is not approved by FDA for any indication, in any population, by any route. In a warning letter dated 31 March 2026, FDA found that products offered for sale as 'Mazdutide' by a US website are unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act, stating that 'No approved applications pursuant to section 505 of the FD&C Act, 21 U.S.C. 355, are in effect for these products' and that introducing or delivering them for introduction into interstate commerce violates sections 301(d) and 505(a). Seven separate queries against FDA's Drugs@FDA database on 2 August 2026 — by generic name, substance name, brand name, active-ingredient name and free text — returned no application for mazdutide. Mazdutide is approved in China, which is a different question with a different answer and no effect on US law.

Warning Letter — Prime Sciences (MARCS-CMS 721805) — FDA, 31 March 2026

“No approved applications pursuant to section 505 of the FD&C Act, 21 U.S.C. 355, are in effect for these products. Accordingly, these products are unapproved new drugs.”

Checked against the source on 2 August 2026.

Is mazdutide approved anywhere in the world?

Yes — in China. China's National Medical Products Administration approved mazdutide, marketed there as Xinermei, in June 2025 'for use (in combination with diet control and increased physical activity) in long-term body weight management in adults with a body-mass index (BMI) of ≥ 28 kg/m2 or with a BMI ≥ 24 kg/m2 together with one or more weight-related comorbidity', and again in September 2025 'for use in glycaemic control in adults with T2D'. That was mazdutide's first approval anywhere. Two things follow that people routinely get wrong. A Chinese approval is not an FDA approval and carries no legal effect in the United States, where FDA has found products sold as mazdutide to be unapproved new drugs. And the approved Chinese indication is narrower than the marketing that surrounds it: it is conditioned on diet control and increased physical activity, and gated on stated BMI thresholds.

Mazdutide: First Approval — Drugs, 30 September 2025

“In June 2025, mazdutide received its first approval, in China, for use (in combination with diet control and increased physical activity) in long-term body weight management in adults with a body-mass index (BMI) of ≥ 28 kg/m2 or with a BMI ≥ 24 kg/m2 together with one or more weight-related comorbidity.”

Checked against the source on 2 August 2026.

Is it legal to buy mazdutide online as a research peptide?

No. FDA has held twice that labelling mazdutide as a research chemical does not make selling it lawful, because intended use is established from the seller's own marketing rather than from its disclaimer. In a warning letter of 31 March 2026, FDA found that 'Despite statements on your product labeling marketing your products for “laboratory research purposes only” and “not for human consumption, medical use or veterinary use,” evidence obtained from your website establishes that your products are intended to be drugs for human use' — making them unapproved new drugs whose introduction into interstate commerce violates sections 301(d) and 505(a) of the Federal Food, Drug, and Cosmetic Act. FDA had made the same finding against a different mazdutide seller on 10 December 2024, over 'RESEARCH USE ONLY' and 'INTENDED AS A RESEARCH CHEMICAL ONLY' labelling. In the 2026 letter FDA cited the seller's own summary of the published GLORY-1 trial as part of the evidence of intended use, so quoting real trial results on a product page is not a defence — in that letter it was the exhibit.

Warning Letter — Prime Sciences (MARCS-CMS 721805) — FDA, 31 March 2026

“Despite statements on your product labeling marketing your products for “laboratory research purposes only” and “not for human consumption, medical use or veterinary use,” evidence obtained from your website establishes that your products are intended to be drugs for human use.”

Checked against the source on 2 August 2026.

Does mazdutide actually work for weight loss?

In two published Phase 3 randomised trials in Chinese adults, yes — on body weight, over 48 to 60 weeks. In GLORY-2 (NCT06164873), a double-blind placebo-controlled trial at 27 hospitals reported in JAMA on 7 June 2026, 461 Chinese adults with obesity received treatment and investigators reported a mean percentage change in body weight from baseline at week 60 of -16.65% in the mazdutide group against -1.50% in the placebo group, with 84.3% versus 33.1% of participants achieving a reduction of at least 5%. In GLORY-1 (NCT05607680), reported in the New England Journal of Medicine in June 2025, investigators randomly assigned 610 Chinese adults with obesity or overweight and reported mean body-weight changes at week 32 of -10.09% and -12.55% in the two mazdutide groups against +0.45% with placebo. Read the boundaries of that evidence. Both trials enrolled Chinese adults in China and were funded by Innovent Biologics; the registered US trials of mazdutide are Phase 2; no cardiovascular or kidney outcomes trial of mazdutide has reported; and gastrointestinal adverse events were common, with the JAMA authors concluding that participants receiving the drug 'experienced gastrointestinal adverse reactions compared with those receiving placebo'. None of it describes a vial bought from a research-peptide vendor, which was not what these trials administered.

Treatment With 9-mg Mazdutide for Weight Reduction in Chinese Adults With Obesity: The GLORY-2 Randomized Clinical Trial — JAMA, 7 June 2026

“At week 60, the mean percentage change in body weight from baseline was -16.65% (95% CI, -18.19% to -15.12%) in the mazdutide group compared with -1.50% (95% CI, -3.43% to 0.43%) in the placebo group (between-group difference, -15.15% [95% CI, -17.22% to -13.09%]; P < .001).”

Checked against the source on 2 August 2026.

Is mazdutide being tested in the United States?

Yes, at Phase 2. Eli Lilly and Company has run registered mazdutide trials at US sites: NCT06124807, a Phase 2 double-blind trial of LY3305677 (mazdutide) against placebo for weight management at 29 US sites, which enrolled 179 participants, completed on 9 July 2025 and has results posted on ClinicalTrials.gov; and NCT06817356, a Phase 2 proof-of-concept trial in alcohol use disorder at 25 US sites, which enrolled 308 participants and completed on 19 May 2026. Lilly's CWMM master protocol NCT06143956 was recruiting at 54 sites in the United States and Argentina as of 2 August 2026 with LY3305677 listed among its interventions. Two limits on what that means. Every Phase 3 trial of mazdutide located for this record is registered by Innovent Biologics and conducted in China, so there is no US Phase 3 programme on the registry; and a trial being registered, recruiting or completed says nothing about whether or when FDA will approve anything. Trial registrations on ClinicalTrials.gov are self-reported and are not vetted before they appear.

A Phase 2, Parallel-Group, Double-Blind, 4-Arm Study to Investigate Weight Management With LY3305677 Compared With Placebo and in Adult Participants With Obesity or Overweight — ClinicalTrials.gov, 9 July 2025Checked against the source on 2 August 2026.

Can a compounding pharmacy make mazdutide in the US?

Mazdutide appears nowhere in FDA's list of bulk drug substances nominated for use in compounding under section 503A — not in Category 1, not Category 2, not Category 3 — as verified against the version of that document updated 14 May 2026. It is also not an active ingredient in any FDA-approved drug product: seven Drugs@FDA queries on 2 August 2026 returned no application for it. Those are the two documents that answer this question, and here is the honest limit of what they show. This record located no FDA letter, notice or guidance addressing compounding with mazdutide by name, of the kind FDA published for retatrutide in March 2025, so no mazdutide-specific FDA compounding determination is asserted here. Absence from the 503A list is not permission, and it is not a safety finding — it means mazdutide was never part of that evaluation at all.

Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act — FDA, 14 May 2026Checked against the source on 2 August 2026.