Is Reta (Retatrutide) Safe? What the Trials Show and Why Online Reta Is Black Market
Retatrutide, often called reta, produced the largest average weight loss of any medicine tested so far: 25% on the top dose in a large trial. But it is not approved anywhere, it cannot legally be sold or compounded, and the FDA has received reports of two deaths after people took bootleg versions. Here is what the trials show, what the side effects are under medical supervision, and what to do instead if your current GLP-1 is not working.
Key takeaways
- Retatrutide (reta) is an experimental weekly shot from Eli Lilly that acts on three hormone receptors: GLP-1, GIP and glucagon.
- In the TRIUMPH-1 trial, people on the 12 mg dose lost an average of 25% of their body weight at 80 weeks, compared with about 4% on placebo.
- Even with a doctor watching, side effects were common: nausea in about 4 in 10 on the top dose, a skin burning sensation called dysesthesia, and a raised heart rate.
- Reta is not approved anywhere. Anything sold online, by a peptide vendor or a med spa is black market, not compounded, and you cannot know what is in the vial.
- If your current GLP-1 is not working, there are safer next steps: check how your result compares with the trials, then talk with your doctor about the dose, switching medicines or surgery.
What is reta (retatrutide)?
Retatrutide is an investigational weight loss medicine made by Eli Lilly, the company behind Zepbound and Mounjaro. People online call it reta. It is a once-weekly injection.
The easiest way to understand it is by counting the hormone receptors each medicine acts on. Wegovy and Ozempic (semaglutide) act on one, the GLP-1 receptor. Zepbound and Mounjaro (tirzepatide) act on two, GLP-1 and GIP. Retatrutide adds a third, glucagon, which is why it is called a triple agonist. Glucagon may add to weight loss by increasing how much energy the body burns, and it is also the likely reason retatrutide raises heart rate.
Retatrutide is not approved by the FDA or any other regulator. Lilly says it plans to submit it to the FDA in the first quarter of 2027, so the earliest it could reach pharmacies is after that review. In Lilly's own words, it is "an investigational molecule that cannot be legally sold or marketed for human use."
How much weight do people lose on retatrutide?
More than on any approved medicine so far. TRIUMPH-1, published in the New England Journal of Medicine in September 2026, followed 2,339 adults with obesity and without diabetes for 80 weeks. The numbers below count everyone who started the trial, including people who stopped the medicine.
| Weekly dose | Average weight loss at 80 weeks |
|---|---|
| Retatrutide 4 mg | 17.6% |
| Retatrutide 9 mg | 23.7% |
| Retatrutide 12 mg | 25.0% |
| Placebo | 3.9% |
You may see higher numbers, such as 28%, in headlines. Those come from Lilly's announcement and only count people while they stayed on the medicine. The 25% figure is the fairer comparison with other medicines.
People with type 2 diabetes lost less, as they do on every GLP-1. In TRIUMPH-2, which studied adults with obesity and type 2 diabetes, average loss on 12 mg was 18.8% at 80 weeks.
On episode 78 of the Pound of Cure podcast in February 2026, Dr. Matthew Weiner said that people who do not respond to Zepbound, Ozempic or Wegovy may one day respond to orforglipron or retatrutide. That hope still holds. What has changed is the timeline: approval is now expected no earlier than 2027, and in the meantime an illegal market has filled the gap.
What are the side effects of retatrutide?
Even in carefully run trials, with a known, pure product and a doctor raising the dose slowly, side effects were common and went up with the dose. Most were stomach and bowel symptoms, as with other GLP-1 medicines.
| Side effect in TRIUMPH-1 | 4 mg | 9 mg | 12 mg | Placebo |
|---|---|---|---|---|
| Nausea | 28.6% | 38.4% | 42.4% | 14.8% |
| Skin burning sensation (dysesthesia) | 5% | 12% | 13% | 1% |
| Stopped the medicine because of side effects | 4.1% | 6.9% | 11.3% | 4.9% |
In TRIUMPH-2, in people with type 2 diabetes, about 1 in 8 on the 9 mg dose stopped the medicine because of side effects. Low blood pressure was also more common with retatrutide than with placebo.
Dysesthesia is less familiar. Lilly defines it as a skin burning sensation and related symptoms. It was not seen with Wegovy or Zepbound at these rates, and in one trial of people with knee arthritis it affected 21% on the top dose.
Heart rate went up with the dose in the phase 2 trial, peaked at about 24 weeks and then came down. In a trial of people who already had heart disease, there was no clear difference in heart attacks or strokes between retatrutide and placebo, but there were too few events to be sure either way. A dedicated five-year heart and kidney outcomes trial is still running, with results expected around 2029.
Is reta from online sellers, peptide shops or med spas safe?
No. It's not compounded. It's black market. Because retatrutide is not approved, it cannot legally be compounded by any pharmacy, and the FDA has said so directly. The FDA has sent warning letters to websites selling it, often labeled "for research use only" or "not for human consumption," and recommends that consumers not buy these products, which are of unknown quality and may be harmful.
The harm is starting to show:
- America's Poison Centers logged 249 calls about retatrutide in the first three months of 2026, 460 in the next three months and 862 in the three months ending in September.
- In October 2026, CBS News reported that the FDA had received reports of two deaths after people took bootleg versions. The reports do not prove that the drug caused the deaths, and the FDA has not said whether it verified them.
- Lilly has sued peptide sellers, a med spa and a compounding pharmacy, alleging that products sold as retatrutide have not been vetted by regulators and are more likely to contain contaminants.
When a person gets sick after using black market reta, there are three possibilities: the vial contained something other than retatrutide, or the wrong amount; the drug itself caused a problem that trials have not yet found; or no one was watching for warning signs such as a racing heart, dehydration or not eating enough. A trial or a doctor's office protects against all three. A vial bought online protects against none of them.
If you have taken reta and feel unwell, call Poison Help at 1-800-222-1222 or your doctor, and keep the vial and packaging.
Can I get retatrutide legally?
Only in two ways today. The first is a clinical trial. The second is Lilly's expanded access program, which is limited to adults with a BMI of 35 or higher and at least two serious obesity-related conditions that have not responded to approved treatment, and who cannot join a trial. The request has to come from your doctor, one patient at a time.
For most people, neither route is realistic right now. That makes it more important to get the most from the GLP-1 medicines that are approved. If cost is what is pushing you toward reta, see what GLP-1s cost in Arizona, how insurance coverage works and Medicare GLP-1 coverage.
What should I do if my GLP-1 is not working?
Most people who look for reta are frustrated with the medicine they are on. Before reaching for an unapproved drug, it is worth knowing whether your response is actually poor.
Weight loss on GLP-1s follows a bell curve. Roughly 15% of people lose much more than average, about 15% lose very little, and most land in the middle. A disappointing number at three months can still be a normal response at one year. The free Pound of Cure GLP-1 check compares your weight loss with the clinical trials for your medicine, dose and time on treatment.
If your response really is poor, you still have options to talk through with your doctor:
- Nutrition and habits, which make the biggest difference for people in the middle of the curve, including protein and strength training to protect your muscle.
- A dose change, if you are not yet on the full dose.
- Switching medicines. Some people do much better on semaglutide and others on tirzepatide, although someone who does not respond to one often does not respond well to the other.
- Bariatric surgery, which remains the most effective long-term treatment for people with severe obesity who have not responded to medication. If that may be you, book a consultation.
The Pound of Cure app gives you daily nutrition coaching, a plan built by our registered dietitians and support between doctor visits, whichever medicine you are on.
Frequently asked questions
Is retatrutide FDA approved?
No. Retatrutide is still investigational. Lilly plans to submit it to the FDA in the first quarter of 2027, and it cannot legally be sold or marketed until it is approved.
Is compounded retatrutide legal?
No. Pharmacies cannot legally compound retatrutide because it is not an approved drug and is not on the FDA's lists of substances allowed for compounding. Anything sold as compounded or research-grade reta is black market.
How much weight can you lose on retatrutide?
In the TRIUMPH-1 trial, people on the 12 mg dose lost an average of 25% of their body weight over 80 weeks, counting everyone who started. People with type 2 diabetes lost less, about 19% on the same dose.
What are the most common side effects of retatrutide?
Nausea, diarrhea, constipation and vomiting were the most common. A skin burning sensation called dysesthesia and a higher heart rate were also more common than on placebo.
Did people die from taking reta?
The FDA received reports of two deaths in people who took bootleg versions of retatrutide. The reports do not prove the drug caused the deaths, and the products' contents are unknown.
When will retatrutide be available?
Not before Lilly files with the FDA in early 2027 and the FDA completes its review, so likely not until late 2027 at the earliest. Until then, the only legal access is through a clinical trial or Lilly's expanded access program.