Peptide News This Week: Retatrutide, BPC-157 (Oct 1, 2026)

October 1, 2026 · What changed in peptides this week, what it means for you, and what didn’t change.

In a large trial published this week, Eli Lilly’s experimental weight-loss drug retatrutide helped people with type 2 diabetes lose about a fifth of their body weight. It still isn’t FDA-approved, and Lilly says it won’t ask for approval until early 2027. The FDA also hasn’t taken the next step toward letting pharmacies make BPC-157 and five other peptides, even though its outside advisers voted yes more than two months ago. For now, nothing has changed about how you can legally get either one.

This is our first weekly roundup. Each week we cover what actually moved in the peptide world, what it means for you, and what stayed the same.

This week at a glance

Retatrutide’s diabetes trial results are out. Lilly reported its TRIUMPH-2 trial on Sept 29.
The FDA hasn’t moved on BPC-157 and five other peptides. There’s still no proposed rule, two months after the advisory vote.
What the FDA’s “research use only” crackdown actually says. We explain the August warning letters and a federal prison sentence.
Regulatory Tracker: no status changes this week.

The big one: retatrutide’s diabetes trial (TRIUMPH-2)

Lilly announced the results of TRIUMPH-2 on September 29, and the full study was published the same day in The Lancet, a major peer-reviewed medical journal. The trial followed 1,152 adults for 80 weeks. All of them had type 2 diabetes and also had obesity or overweight. (Lilly release; ClinicalTrials.gov NCT05929079)

Retatrutide is a “triple agonist,” which means it acts on three hormones that control appetite and blood sugar at the same time. For comparison, tirzepatide acts on two of those hormones and semaglutide acts on one.

The trial tested three dose levels against a placebo, which is an inactive look-alike shot. Here are Lilly’s reported results:

Group	Average weight loss	Drop in A1C
Lowest dose	12.7%	1.4 points
Middle dose	19.1%	1.6 points
Highest dose	20.8%	1.5 points
Placebo	4.0%	0.2 points

A1C is a blood test that shows your average blood sugar over the past few months. A drop of 1.4 to 1.6 points means blood sugar control improved substantially. Lilly also reports that up to 79.2% of people on retatrutide reached an A1C of 6.5% or lower, a level often used as a treatment goal for people with diabetes. Lilly notes these are “efficacy estimand” figures, which means they describe people who kept taking the drug as planned, so results across everyone who started may run somewhat lower.

In plain terms: people on the highest dose lost roughly one-fifth of their body weight. That matters more than it might seem, because people with diabetes usually lose less weight on these drugs than people without it. NBC News reports that semaglutide and tirzepatide typically produce about 10–15% weight loss in diabetes trials, and NBC describes retatrutide’s result as the biggest yet in this group (NBC). That is NBC’s comparison, not ours. No trial has tested these drugs against each other directly, so it remains an informed guess, not a verdict.

Side effects, straight

Most of the common side effects involved the stomach and gut: diarrhea, nausea, constipation, decreased appetite, and vomiting.

Here is the share of people in each group who stopped taking the drug because of side effects:

Group	Stopped due to side effects
Lowest dose	3.8%
Middle dose	11.6%
Highest dose	7.7%
Placebo	4.9%

You might have heard that retatrutide’s results come with a lot of people quitting. The numbers above only partly back that up. At the highest dose, 7.7% stopped because of side effects, which isn’t far above the 4.9% who stopped on placebo. The middle dose was a different story, at 11.6%. These figures come from Lilly, which paid for the trial, although the study passed peer review at The Lancet. This trial also can’t tell us anything about safety beyond 80 weeks.

For the full side-effect data across all of retatrutide’s trials, see our guide to retatrutide side effects.

Where it stands with the FDA

Retatrutide is not FDA-approved for any use, as of October 2026. Lilly says it plans to submit a Biologics License Application (the formal request asking the FDA to approve a drug of this type) in the first quarter of 2027.

Can you get it?

Some people can, but only through two legitimate routes. The first is a Lilly clinical trial. The second is Lilly’s expanded-access program, which lets some patients who can’t join a trial receive an experimental drug under a doctor’s care. AJMC, citing STAT and Reuters, reported that Lilly confirmed the program on August 3, 2026. It’s narrow: it’s meant for adults who can’t enroll in trials and who have severe obesity with serious complications. The exact eligibility rules differ between those reports (AJMC). In both routes, the drug is made by Lilly and a doctor monitors you.

Any “retatrutide” from a med spa, wellness clinic, compounding pharmacy, or “research use only” website comes from outside those routes. Compounding is when a pharmacy mixes a custom version of a drug for one patient. There is no legal compounding path for an unapproved drug that’s still in trials. Products sold through those channels come with no FDA manufacturing oversight and no verified purity or dose accuracy. Research-use websites add no medical supervision at all. A clinic may involve a clinician, but that doesn’t change what’s in an unapproved, unverified vial. The FDA named retatrutide in its August warning letters to research-use sellers (more on that below).

For the full background, see our retatrutide explainer and our GLP-1 weight-loss hub.

Still waiting: the FDA hasn’t acted on BPC-157 and five other peptides

In July, the FDA’s Pharmacy Compounding Advisory Committee met to review seven peptides. This is a panel of outside experts that advises the agency on which ingredients pharmacies should be allowed to use. It reviewed BPC-157, KPV, TB-500, and MOTS-c on July 23, and emideltide, Semax, and Epitalon on July 24 (FDA meeting page).

According to news reports from NBC, ABC, and Reuters (via PharmExec), the advisers voted to recommend six of the seven, all except emideltide. The FDA’s meeting page doesn’t post the vote results. The agency’s own staff had recommended against all seven.

What hasn’t happened

The FDA has not published a proposed rule adding any of the six to the 503A bulks list, which is the official list of ingredients pharmacies may legally use to compound. FDA’s own page still lists all six in a “nominated but withdrawn” table (FDA Category 2 page; FDA 503A page). PharmExec reported on September 29–30 that the rulemaking has stalled (PharmExec).

What it means for you

BPC-157 is not FDA-approved and is not on FDA’s list of ingredients pharmacies may legally compound, as of October 2026. The same goes for KPV, TB-500, MOTS-c, Semax, and Epitalon: none of them is FDA-approved, and none is on FDA’s list of ingredients pharmacies may legally compound, as of October 2026.

An advisory vote is a recommendation, not a rule. First, the FDA has to publish a proposal. Then it takes public comments, and only after that can it issue a final rule. Dustin Robinson of LumaLex Law, quoted by PharmExec, estimated 8–12 months. Attorneys at Buchanan Ingersoll & Rooney say there’s no reliable timetable, noting FDA once took over two years to finalize a similar rule. Until then, a licensed pharmacy can’t legally compound these peptides. They’re widely sold by “research use only” websites, without a prescription or medical oversight. A Mintz attorney noted in July that compounding pharmacies, telehealth platforms, med spas, and wellness clinics also advertise them, though the vote didn’t change the law. For more on the legal difference, read what “compounding-eligible” actually means.

The case for the vote, fairly stated

The advisers who voted yes, according to Medscape and PharmExec, argued that people are already buying these peptides from unregulated websites. Regulated pharmacy compounding, they said, would be safer than that gray market. According to Reuters via PharmExec, six of the panel’s eight new appointees run or work for clinics that offer peptides. Supporters also pointed to these peptides’ long use by licensed practitioners, and argued that because they’re hard to patent, no company has much reason to pay for full FDA approval trials (McDermott Will & Schulte). Scott Brunner, CEO of the Alliance for Pharmacy Compounding, a trade group whose members would make these products, said a lawful pharmacy route would bring better oversight, including mandatory adverse-event reporting (reports of side effects to regulators) and ingredients from FDA-registered suppliers (Drug Topics).

That argument holds together on harm reduction: a licensed pharmacist accountable for what’s in the vial is more oversight than none. The patent point also helps explain why the evidence is thin. But explaining a gap doesn’t fill it. FDA’s scientists found the available studies, including five trials of BPC-157, too short and too small to establish safety or effectiveness (AJMC).

Track each compound’s status on our BPC-157 tracker page and the full Regulatory Tracker.

Context: what the FDA’s “research use only” crackdown actually says

This section explains background events rather than news from this week. McDermott Will & Schulte, a law firm, published an analysis on September 24 that brought the topic back into the conversation.

On August 24, the FDA sent warning letters to five online sellers. It posted them on September 1. The sellers were Peak Performance Peptides, Royal Peptides, NuScience Peptides, Peptide Partners, and TXP Innovations (Tex Peptides). The links go to the FDA’s letters, not the sellers.

The FDA didn’t take the “research use only” labels at face value. It looked at what else the sites offered: dosing information, injection instructions, dose calculators, and bacteriostatic water, which is sterile water used to mix a powder into an injectable liquid. The agency concluded those showed the products were meant for people. The letters named products including semaglutide, tirzepatide, retatrutide, tesamorelin, elamipretide (SS-31), and bremelanotide (PT-141). McDermott notes that none of the letters named the six peptides the advisory panel recommended. A warning letter is FDA’s formal statement that it believes the law was broken, not a court ruling, and recipients can respond and dispute it (FDA).

There was also a criminal case. On July 30, 2026, the Department of Justice announced that Matthew Kawa, owner of Paradigm Peptides, was sentenced to 70 months in federal prison (DOJ). According to DOJ, many products sold as “SARMs” were actually mislabeled testosterone. Products were also imported without the quality testing the company claimed. He had received FDA warning letters in 2020 and 2022.

The plain takeaway: “research use only” describes the level of oversight. It says nothing either way about quality or legality. It means no prescription, no FDA manufacturing oversight, and no guarantee of what’s in the vial. Some research-use sellers publish independent lab results, called certificates of analysis. That’s more than nothing, but a certificate still doesn’t make a product verified, safe, or legal. As the Paradigm case shows, quality claims can be false. For the basics, see what peptides are.

Also this week

Empower Pharmacy warning letter (recently posted). In a letter dated September 18, the FDA told Empower Pharmacy that two of its products were essentially copies of approved drugs: semaglutide with vitamin B12, and tirzepatide with niacinamide (a form of vitamin B3). The FDA said Empower made them in “inordinate amounts” without patient-specific justification. The letter also cited problems with sterility testing, the checks that make sure an injectable isn’t contaminated (FDA letter).

The plain takeaway, in FDA’s view, is that adding a vitamin doesn’t make a compounded GLP-1 a different drug. Empower can respond to the letter. Brand semaglutide and tirzepatide are FDA-approved and available by prescription. That includes telehealth clinics that prescribe after an online visit. A compounding pharmacy has a licensed pharmacist accountable for what’s in the vial, but its product isn’t FDA-approved. More in our GLP-1 hub, plus semaglutide and tirzepatide.

Switching to the semaglutide pill. Novo Nordisk presented an analysis at EASD, a major European diabetes conference. It looked at 194 patients on the Ro telehealth platform who switched from injectable semaglutide or tirzepatide to the oral semaglutide pill. They lost an average of 4.1% of their body weight (8.8 lbs) over the three months after switching (PharmExec). Treat this result cautiously. The group was small, and the analysis was retrospective, meaning researchers looked back at existing records instead of running a controlled trial. The drug’s maker presented it using data from a telehealth partner.

Regulatory Tracker: changes this week

No status changes this week. We checked FDA’s compounding category pages on October 1, 2026. BPC-157, KPV, TB-500, MOTS-c, Semax, and Epitalon remain off FDA’s list of ingredients pharmacies may legally compound, and retatrutide remains unapproved. See the full Regulatory Tracker.

What we’re watching next

Any proposed rule in the Federal Register on the six peptides the advisory panel recommended.
Lilly’s remaining late-stage retatrutide trial results, and its planned FDA submission in early 2027.
Final action on the FDA’s April 30, 2026 proposal to stop large outsourcing pharmacies (called 503B facilities) from using semaglutide, tirzepatide, and liraglutide as compounding ingredients. Public comments closed June 29, and we found no final rule as of October 1.
More FDA warning letters to online sellers.

See every weekly roundup

Sources

This article is for informational purposes only and isn’t medical advice. Talk to a licensed healthcare provider before using any peptide, especially one that’s unapproved or compounded. We don’t yet work with a credentialed medical reviewer — see our editorial policy for what that means for this article.

Author

Jake Cutler

Jake Cutler is a writer, teacher, and veteran editorial strategist. Previous to co-founding The Peptide Authority, Jake ran online publications in a number of highly regulated industries (residential solar, financial advising, and kids tech).

Peptide News This Week: Retatrutide’s Big Diabetes Trial, and Why BPC-157 Is Still in Limbo

This week at a glance