Retatrutide: not just weight loss - what new studies show

Retatrutide is an investigational triple agonist of GIP, GLP-1 and glucagon receptors.

This is its fundamental difference from semaglutide, which affects GLP-1, and tirzepatide, which works through GIP and GLP-1.

That is, researchers are studying not just another way to suppress appetite, but a molecule with a triple mechanism of influence on the regulation of eating behavior and metabolism.

Retatrutide for weight loss: what did the studies show?

Even in phase 2, the results attracted a lot of attention. After 48 weeks, the average body weight loss was up to 24.2% in the 12 mg group, while in the placebo group it was 2.1%.

And in 2026, the results of large phase 3 studies appeared.

In one of them, which involved 2339 obese adults, the average weight loss at the highest dose studied was about 25%.

That is, the question “why do I constantly lose weight and then gain it back?” is increasingly being considered by medicine not only as a problem of willpower, but in the context of biological regulation of body weight.

Constantly wanting to eat and craving sweets

One of the main reasons why people are interested in GLP-1 therapy is a strong appetite.

A person can perfectly understand how to eat, but in the evening open the refrigerator again. Or eat normally and after an hour think about sweets.

The mechanisms of GLP-1 and GIP are associated with the regulation of satiety and food intake. That is why Retatrutide is being studied not as a “fat burner”, but as a metabolic therapy for obesity.

Fatty liver: one of the most interesting results

This is a point that is talked about much less.

In a randomized study of people with metabolic-associated steatotic liver disease, Retatrutide significantly reduced the amount of fat in the liver.

After 24 weeks, the average relative reduction in liver fat was approximately 81–82% in the 8 and 12 mg groups, compared with virtually no change in the placebo group.

For people with overweight, insulin resistance, and fatty liver, this is one of the most interesting areas of further research.

Do your knees hurt because of being overweight?

Interesting data emerged here too.

The phase 3 study separately analyzed 574 participants with knee osteoarthritis.

It was not only body weight that decreased with Retatrutide - the researchers recorded a statistically significant reduction in knee pain compared to placebo.

This is an important point: sometimes a person wants to start moving more, but the excess weight itself prevents them from doing so due to joint pain.

Snoring and sleep apnea

Another problem that many people do not associate with being overweight for years is obstructive sleep apnea.

A person snores, has trouble sleeping, wakes up feeling groggy, wants to sleep during the day, and may have repeated episodes of respiratory arrest at night.

In the same phase 3 study among participants with obstructive apnea, Retatrutide significantly reduced the number of apnea and hypopnea episodes per hour of sleep.

Insulin resistance and diabetes

In 2026, Lilly reported the results of TRIUMPH-2 among people with overweight or obesity and type 2 diabetes. 20.8% in 80 weeks, and HbA1c also decreased significantly.

This once again shows why modern obesity treatment should not be reduced solely to the number on the scale.

And what about Retatrutide and oncology?

Here it is important not to exaggerate.

On the Internet, you can already find claims about the “anti-cancer properties” of GLP-1 drugs. But Retatrutide is not currently an anticancer therapy, and there is no clinical evidence that it treats cancer.

At the same time, obesity and metabolic disorders are associated with the risk of a number of diseases, so the impact of obesity treatment on long-term risks, including cancer, is an important area of ​​research.

But there is a huge difference between the words “a possible connection is being studied” and “the drug protects against cancer.”

I would not promise my patients the latter.

Why do tests still need to be monitored for Retatrutide?

Even a very effective molecule is no substitute for normal nutrition and monitoring the body’s condition.

If a person has drastically reduced the amount of food they eat and at the same time stopped getting enough protein, iron, and other nutrients, after a few months they may have a completely different problem: weakness, hair loss, loss of muscle mass, and deficiencies.

Therefore, my position is simple: the goal is not just to see a minus on the scales. The goal is to lose weight so that after losing weight, the body does not have to recover for another six months.

Are there side effects?

Yes.

In clinical trials, the most common adverse events were gastrointestinal symptoms. An early study also observed a dose-dependent increase in heart rate, which reached a maximum at about 24 weeks and then decreased.

So more does not mean better, and faster dose increases do not mean faster and safer weight loss.

Is Retatrutide a ready-made drug?

This is also a fundamental point.

As of October 2026, Retatrutide is still an investigational molecule. Lilly reports positive results from several phase 3 studies and plans to submit documents to regulators, but this does not mean that any product with the inscription “Retatrutide” that is already on the market on the Internet, is the same drug that was used in clinical trials.

Therefore, the results of studies of the original molecule cannot be automatically transferred to third-party products.

What is the result?

Retatrutide is interesting not only for the number on the scales.

Today, effects on obesity, glycemic control, fatty liver disease, knee osteoarthritis pain, and obstructive sleep apnea are already being studied or shown.

But I would not turn a promising molecule into a “cure for everything.” Especially when it comes to oncology.

The very normal explanation of what has already been proven, what is only being studied, and what is still an exaggeration, is today much more valuable than another promise of magical weight loss.