From Prediabetes to Prevention: How Peptide Research Is Changing Type 2 Diabetes

For decades, type 2 diabetes has largely been discussed as a condition to manage once blood glucose becomes too high. Today, peptide-based metabolic research is beginning to change that conversation.

Semaglutide, tirzepatide and newer multi-receptor peptides are being studied across a much wider metabolic spectrum — from established type 2 diabetes to obesity, insulin resistance and prediabetes.

Some of the results are striking.

In long-term research involving people with obesity and prediabetes, progression to type 2 diabetes was dramatically lower during treatment with tirzepatide than with placebo. Large studies with semaglutide have also shown that many participants with prediabetes returned to normal glucose ranges while receiving treatment.

The important question is therefore becoming broader than simply “How can high blood sugar be lowered?”

Researchers are increasingly asking whether metabolic deterioration can be influenced much earlier — before type 2 diabetes becomes established.

Type 2 diabetes usually develops gradually

Type 2 diabetes does not normally appear overnight.

Long before diagnosis, the body may become progressively less responsive to insulin. The pancreas compensates by producing more insulin, but over time this compensation may become insufficient to maintain normal glucose levels.

Blood glucose begins to rise. Prediabetes may develop. In some people, the process eventually progresses to type 2 diabetes.

This is one reason the period before diabetes develops has become such an important area of metabolic research.

If the trajectory can be changed during this stage, researchers may have an opportunity to do more than manage elevated glucose after diabetes is established.

Why GLP-1 became so important

GLP-1 is a naturally occurring hormone released from the intestine after eating. Among its functions, it helps regulate glucose-dependent insulin secretion, glucagon, appetite and food intake.

GLP-1 receptor agonists were developed to reproduce and extend some of these biological signals.

Semaglutide is one of the best-known examples.

Its role in type 2 diabetes is not simply related to weight reduction. Clinical research has demonstrated improvements in glucose control, and cardiovascular outcome studies have expanded the discussion beyond HbA1c alone.

In the SUSTAIN-6 cardiovascular trial, 3,297 people with type 2 diabetes were followed for approximately two years. The primary cardiovascular outcome occurred in 6.6% of participants receiving semaglutide compared with 8.9% receiving placebo.

This helped establish a broader idea that has become increasingly important in diabetes research: a metabolic therapy can be evaluated not only by what happens to a glucose measurement, but also by what happens to the wider health risks associated with diabetes.

Prediabetes may be an especially important window

Prediabetes occupies an interesting position.

Blood glucose regulation is already impaired, but the threshold used to diagnose type 2 diabetes has not yet been reached.

Research with semaglutide provides an important example of what may be possible during this period.

An analysis of the multinational STEP 1, STEP 3 and STEP 4 trials examined more than 1,500 participants who had prediabetes at baseline.

After 68 weeks, the proportion reaching normal glucose status was substantially higher with semaglutide than with placebo.

In STEP 1, 84.1% of participants with prediabetes receiving semaglutide had normoglycemia, compared with 47.8% receiving placebo.

STEP 3 showed 89.5% versus 55.0%, while STEP 4 showed 89.8% versus 70.4%.

Semaglutide was also associated with improvements in HbA1c, fasting glucose and measures of insulin resistance.

These findings do not mean that diabetes risk has permanently disappeared. They do show something important: prediabetes is not necessarily a one-way journey toward type 2 diabetes.

A much larger study strengthened the picture

The SELECT trial provided another opportunity to examine this question on a much larger scale.

SELECT included 17,604 people with overweight or obesity and established cardiovascular disease but without diabetes.

By week 156, 69.5% of participants receiving semaglutide had biochemical normoglycemia, compared with 35.8% receiving placebo.

Progression to biochemical diabetes showed the opposite pattern.

By the same point, biochemical diabetes had occurred in 1.5% of participants receiving semaglutide compared with 6.9% receiving placebo.

These results do not establish permanent prevention after treatment ends. But they add to the evidence that peptide-based metabolic therapies can influence the trajectory of glucose regulation before diabetes is established.

Tirzepatide added another metabolic signal

The next major development was the combination of more than one hormonal pathway in a single molecule.

Tirzepatide activates both GIP and GLP-1 receptors.

The SURPASS-2 trial directly compared tirzepatide with semaglutide in 1,879 people with type 2 diabetes.

Participants began with an average HbA1c of approximately 8.28%.

After 40 weeks, average HbA1c reductions were approximately 2.01 percentage points with 5 mg tirzepatide, 2.24 points with 10 mg and 2.30 points with 15 mg, compared with 1.86 points with semaglutide 1 mg.

Body-weight reductions were also greater in the tirzepatide groups.

The study demonstrated something important for the future of peptide research: targeting multiple metabolic receptors within one molecule could produce substantial effects on both glucose regulation and body weight.

Then came the three-year prediabetes data

Perhaps one of the most interesting developments came from the long-term SURMOUNT-1 research.

Among participants with both obesity and prediabetes, treatment continued for 176 weeks — more than three years.

During that period, type 2 diabetes was diagnosed in 1.3% of participants receiving tirzepatide compared with 13.3% receiving placebo.

That difference deserves attention.

It does not mean tirzepatide permanently prevented diabetes in every participant who otherwise would have developed it. The study measured progression during a defined period, and the participants were receiving active treatment for most of that time.

There was also a 17-week period after treatment was stopped. By week 193, type 2 diabetes had been diagnosed in 2.4% of participants originally assigned to tirzepatide compared with 13.7% assigned to placebo.

The increase after withdrawal is itself informative.

It suggests that part of the protection may depend on the metabolic environment created while treatment is active.

Even with that limitation, the difference observed over three years raises an important possibility: peptide-based metabolic treatment may have a role not only after diabetes develops, but potentially during the years in which the disease is developing.

Why weight and diabetes are so closely connected

It would be too simple to attribute all of these results to weight loss.

At the same time, body weight clearly matters.

Excess adipose tissue, particularly when accompanied by insulin resistance, can contribute to the metabolic conditions associated with progression toward type 2 diabetes.

Reducing body weight can therefore improve glucose regulation through several mechanisms.

But incretin-based therapies also act directly through hormonal pathways involved in glucose-dependent insulin secretion, glucagon regulation, appetite and energy intake.

The result is an increasingly integrated view of metabolic disease.

Obesity, insulin resistance, prediabetes and type 2 diabetes are not completely separate problems. For many people, they represent different stages or expressions of interconnected metabolic dysfunction.

What happens when a third receptor is added?

Retatrutide takes the multi-receptor concept another step.

It is a single investigational peptide designed to activate GIP, GLP-1 and glucagon receptors.

Retatrutide remains investigational and is not currently approved for human use. Clinical trials are evaluating its safety and efficacy in type 2 diabetes, obesity and related metabolic conditions.

In 2026, results from the Phase 3 TRANSCEND-T2D-1 trial provided a clearer picture of its potential role in diabetes research.

The 40-week randomized, double-blind trial included 537 adults with type 2 diabetes whose glucose levels were inadequately controlled with diet and exercise alone. The study was conducted at 48 sites in the United States, Mexico and India.

Participants received retatrutide at doses of 4 mg, 9 mg or 12 mg, or placebo.

At 40 weeks, average HbA1c reductions were approximately 1.69 percentage points with 4 mg, 1.86 points with 9 mg and 1.94 points with 12 mg, compared with 0.81 points with placebo.

Body weight also changed substantially. Average reductions were approximately 11.5%, 13.9% and 15.3% across the three retatrutide groups, compared with 2.6% with placebo.

The results are important because they move the triple-agonist concept beyond earlier Phase 2 research and into Phase 3 clinical evidence in people with type 2 diabetes.

They do not establish retatrutide as an approved diabetes treatment, and further research remains important for understanding its longer-term safety, efficacy and potential clinical role.

Scientifically, however, the results illustrate how metabolic peptide research is progressing from single-receptor therapies toward molecules designed to act across several interconnected metabolic pathways.

And researchers are exploring combinations beyond GLP-1 and GIP

Another direction involves the amylin pathway.

Cagrilintide is a long-acting amylin analogue. When combined with semaglutide, the combination is known as CagriSema.

The Phase 3 REDEFINE 2 trial studied this combination specifically in adults with overweight or obesity and type 2 diabetes.

The trial was conducted across 12 countries, providing another international dataset for the developing field.

The significance is broader than any single result.

Researchers are increasingly testing whether metabolic pathways can be combined in different ways — GLP-1 with GIP, GLP-1 with glucagon, GIP with glucagon, or GLP-1 with amylin — to influence glucose regulation, appetite, body weight and wider metabolic health simultaneously.

Are we moving from treatment toward prevention?

This question requires careful wording.

Semaglutide and tirzepatide have produced strong evidence that glucose status can improve substantially during treatment. Long-term tirzepatide research has also shown a markedly lower rate of progression from prediabetes to type 2 diabetes during the study period.

But preventing diabetes for several years while treatment is active is not necessarily the same as permanently eliminating the underlying risk.

That distinction matters.

Researchers still need to understand what happens over much longer periods, what happens after treatment is discontinued, which people benefit most and how much of the effect comes from weight reduction versus direct metabolic signaling.

Even with those unanswered questions, the direction of research is encouraging.

The scientific conversation is increasingly moving upstream — from treating elevated glucose after diabetes develops toward identifying and influencing the metabolic changes that occur before it.

The future may involve more than lowering blood sugar

The development of peptide-based metabolic therapies has moved quickly.

GLP-1 receptor agonists demonstrated that one hormonal pathway could substantially influence glucose regulation and body weight.

Dual agonists showed what could happen when another pathway was added.

Triple agonists and amylin combinations are now testing how much further that principle can be developed.

The goal is becoming broader as well.

For people who already have type 2 diabetes, controlling glucose remains essential. But modern research is increasingly examining body weight, cardiovascular risk, kidney health, insulin resistance and the possibility of delaying progression toward diabetes in people who have not yet developed it.

There is still much to learn, and not every investigational peptide will ultimately become an approved therapy.

But the clinical evidence already points toward an important change in metabolic medicine.

The future of diabetes research may not be limited to managing the disease after it appears. Increasingly, the question is how early its metabolic trajectory can be changed.