Can Your Pancreas Start Working Again With Type 1 Diabetes?

Most people with type 1 diabetes retain at least some insulin-producing beta cells, even decades after diagnosis, and several experimental therapies are now aimed at protecting, regrowing, or replacing them. The pancreas does not go completely dark in the way textbooks once suggested. But “start working again” overstates what happens naturally and what medicine can currently achieve. The real picture is more interesting: a mix of stubborn biological persistence, a brief early window where the disease sometimes appears to pause, and a wave of research that is genuinely closer than ever to restoring meaningful beta cell function.

Beta Cells That Refuse to Die

For years, the standard explanation was that in type 1 diabetes, the immune system destroys all beta cells. That turns out to be an oversimplification. Autopsy studies and blood tests show that many people with long-standing type 1 diabetes still have some beta cells quietly producing tiny amounts of insulin. A review of human pancreatic samples and functional studies found that persistent low-level beta cell function is relatively common in long-standing type 1 diabetes, especially in people diagnosed as adults, though the total number of surviving beta cells is vastly reduced.¹

How many people are we talking about? In a study of people who had lived with type 1 diabetes for fifty or more years (the “Joslin Medalists”), roughly a third still had detectable C-peptide in their blood, a marker that beta cells are releasing some insulin. Postmortem examination of their pancreases confirmed that every single one had at least scattered insulin-positive cells.² Another long-term follow-up found that about one in eight participants still had detectable C-peptide after 35 years, and those with higher residual levels experienced far fewer severe low blood sugar episodes.³

These surviving cells are not producing nearly enough insulin to eliminate the need for injections. But their presence matters. Even a small amount of endogenous insulin production smooths out blood sugar swings, reduces the frequency of dangerous lows, and makes the disease easier to manage. The question researchers are now asking is whether those remaining cells can be protected, coaxed into replicating, or supplemented with new ones.

The Honeymoon Phase

Shortly after diagnosis, many people with type 1 diabetes experience a period where their insulin needs drop, sometimes dramatically. Blood sugars become easier to control, and it can feel like the disease is retreating. This is the “honeymoon phase,” and it typically lasts weeks to months, though it occasionally stretches beyond a year. During this window, the surviving beta cells rally and temporarily produce enough insulin to reduce the external dose.⁴ Clinical remission during this phase is sometimes defined as needing very low insulin doses while maintaining good blood sugar control.⁵

The honeymoon ends because the autoimmune attack on beta cells continues. Starting insulin therapy reduces the workload on remaining beta cells, which helps them survive a bit longer, but it does not stop the immune system. Researchers consider this phase the most promising window for intervention precisely because there are still meaningful numbers of beta cells left to save. If the immune assault can be paused or blunted during the honeymoon, more beta cells survive, and the disease becomes milder for longer.

Drugs That Slow the Immune Attack

The most clinically advanced approach to preserving beta cells is immunomodulation, using drugs that dial back the specific immune response destroying beta cells without wiping out the entire immune system. The furthest along is teplizumab, an anti-CD3 antibody that was approved by the FDA in 2022 for delaying the onset of type 1 diabetes in high-risk individuals. In people who already have the disease, a large trial showed that teplizumab-treated patients maintained significantly higher C-peptide levels than those given a placebo at 78 weeks after diagnosis. About 95% of the treatment group kept clinically meaningful insulin production, compared with roughly 79% of the placebo group.⁶ An earlier trial confirmed that this preservation held at two years.⁷

Golimumab, a TNF-alpha blocker already used for rheumatoid arthritis, has shown similar promise in young people with newly diagnosed type 1 diabetes. In a controlled trial, participants on golimumab retained significantly more insulin production at one year, and about 43% met criteria for partial remission compared with just 7% of the placebo group.⁸ Golimumab works by neutralizing a specific inflammatory molecule involved in beta cell destruction.⁹

One trial combined an immunomodulatory antibody targeting IL-21 with liraglutide, a GLP-1 receptor agonist. The combination reduced the decline in meal-stimulated insulin production to just 10% over about a year, compared with a 39% decline in the placebo group. That combination approach, pairing immune modulation with a drug that supports beta cell health, produced better preservation than either drug alone.¹⁰

All of these therapies slow the loss of beta cells rather than restoring them to normal. They buy time. The benefit is real and measurable, but nobody has yet shown that any immune-modulating drug can permanently halt the autoimmune process in type 1 diabetes.

Can Beta Cells Actually Regenerate?

The pancreas has more regenerative potential than scientists assumed even twenty years ago. Several pathways have been identified in animal studies. Beta cells can replicate on their own, though they do so very slowly in adults. Other pancreatic cells can also convert into beta cells under the right conditions.¹¹

One striking example involves alpha cells, the neighboring cells in pancreatic islets that normally produce glucagon. Researchers delivered two genes (Pdx1 and MafA) to alpha cells in diabetic mice using a viral vector infused through the pancreatic duct. The alpha cells converted into functional beta cells, normalizing blood sugar within two weeks. When these mice were followed for six months, they remained non-diabetic, and the converted cells appeared to be stably maintained as beta cells.¹²

A different regeneration route runs through the pancreatic ducts. A 2025 study using long-term intravital imaging in living tissue demonstrated that new insulin-producing cells arose directly from the ductal lining of the pancreas, with net islet volume growing by roughly 50% over the observation period. The researchers also confirmed that the same process appeared to occur in human pancreatic tissue samples.¹³ In a separate line of work, knocking out a single gene (ALDH3B2) in human pancreatic duct cells was enough to trigger their conversion into beta-like cells that responded to glucose and lowered blood sugar in diabetic animals.¹⁴

None of these regeneration strategies has been tested in people with type 1 diabetes yet. And even if new beta cells can be produced inside the body, they would face the same autoimmune attack that destroyed the originals. Any regeneration strategy has to be paired with immune protection to succeed long-term.

Fasting-Mimicking Diets and Beta Cell Reprogramming

A line of research from Valter Longo’s lab explored whether cycles of a fasting-mimicking diet could trigger beta cell regeneration. In mouse models, repeated cycles of the diet activated gene programs associated with early pancreatic development and led to the generation of new insulin-producing cells. In mice with chemically induced type 1-like diabetes, the diet reduced fasting blood sugar and increased beta cell numbers.¹⁵ When the researchers exposed human pancreatic islets from both healthy donors and people with type 1 diabetes to serum collected from fasting-diet subjects, they observed increased expression of genes tied to insulin production and early cell development.¹⁶

These findings are genuinely interesting, but the human data so far is limited to lab-dish experiments using blood serum. No clinical trial has shown that fasting cycles regenerate beta cells in living people with type 1 diabetes. Anyone with type 1 diabetes who experiments with prolonged fasting without close medical supervision is at serious risk of dangerous blood sugar drops. This is a space to watch, not to self-experiment with.

Islet Transplantation

The most direct way to get a pancreas “working again” is to give it new insulin-producing cells from an outside source. Islet transplantation, where clusters of donor islet cells are infused into the liver through the portal vein, has been performed since the early 2000s. A 20-year Italian study of 79 patients reported that 44% achieved insulin independence for a median of six years. Among patients who received a higher dose of islets with optimized immunosuppression, 73% became insulin-independent, and median graft survival extended to nearly ten years. Blood sugar control improved substantially, and serious complications were infrequent.¹⁷ Multiple centers now report five-year insulin independence rates above 50%.¹⁸

The catch is that transplant recipients need lifelong immunosuppressive drugs, which carry their own health risks. In that Italian cohort, 44% experienced side effects from immunosuppression over the follow-up period.¹⁷ Donor supply is also extremely limited: you typically need islets from one or two deceased donors per recipient. This means islet transplantation, as currently practiced, will never be a mass-market solution. It is generally reserved for people with the most brittle, life-threatening forms of type 1 diabetes.

Stem Cell-Derived Beta Cells

If donor islet supply is the bottleneck, the obvious fix is to manufacture beta cells in the lab. Researchers have been working on coaxing human pluripotent stem cells into becoming functional insulin-producing cells, and this effort has moved into clinical trials since 2014.¹⁹ The technology can theoretically produce an unlimited supply of beta cells from stem cell lines.²⁰

The challenge, again, is the immune system. Transplanted stem cell-derived beta cells would be recognized as foreign and attacked, meaning recipients would still need immunosuppression. Two strategies aim to work around this. One is encapsulation: surrounding the cells in protective biomaterials on a tiny scale that allow nutrients and insulin to pass through but block immune cells.²¹ The other is genetic engineering: using tools like CRISPR to modify the stem cells so the immune system does not recognize them as invaders.²²

On the bioengineering side, 3D bioprinting of islet-like structures has advanced to the point where printed constructs maintained normal blood sugar levels in diabetic mice for 90 days and promoted the growth of blood vessels to sustain the transplanted tissue.²³ A 2025 preprint demonstrated that bioprinted human islets maintained viability above 85% and normal insulin secretion dynamics for at least a week, performing comparably to free-floating islets.²⁴ These are still early-stage results, but the trajectory is clear: the goal is a manufactured, immune-protected, implantable insulin-producing tissue that could function like a biological replacement for the damaged pancreas.

CAR-Tregs and Precision Immune Therapy

Perhaps the most futuristic-sounding approach borrows from cancer therapy. Chimeric antigen receptor (CAR) T cell technology, which has transformed the treatment of certain blood cancers, is being adapted for type 1 diabetes. Instead of engineering killer T cells to attack tumors, researchers are engineering regulatory T cells (Tregs) to suppress the autoimmune attack on beta cells. Early lab work showed that insulin-specific CAR Tregs were functionally stable, suppressive, and long-lived in animal models.²⁵

A 2025 study pushed this further, showing that CAR-Tregs engineered to recognize GAD65, a key autoantigen in type 1 diabetes, migrated to human islets, suppressed the immune cells responsible for beta cell destruction, and reversed diabetes in a mouse model designed to mimic human disease. The researchers suggest this approach could allow beta cells to recover once the immune pressure is removed.²⁶ Another group combined CAR-Treg therapy with genetically modified stem cell-derived beta cells, demonstrating that the engineered Tregs could prevent immune destruction of the transplanted cells in living animals.²⁷

None of this has reached human trials for type 1 diabetes yet. But it represents a fundamentally different approach: instead of broadly suppressing the immune system (with all the infection risks that entails), it would selectively retrain the immune cells responsible for the problem. If it works in people, it could pair naturally with either regeneration strategies or stem cell transplants.

Why the Immune Problem Keeps Coming Back

Every strategy for restoring pancreatic function in type 1 diabetes runs into the same wall: the autoimmune process that caused the disease in the first place. Even if you transplant new beta cells, reprogram alpha cells, or coax ductal cells into producing insulin, the immune system still remembers beta cells as targets. Understanding what triggers and sustains this attack matters for figuring out how to stop it.

One important piece of the puzzle is viral. The evidence for a connection between coxsackievirus B infection and the development of type 1 diabetes has strengthened considerably in recent years.²⁸ Research has shown that coxsackievirus can directly infect and kill beta cells.²⁹ If viral infection is a key trigger, then a vaccine against coxsackievirus B, which is in development, could reduce the incidence of type 1 diabetes in the first place, potentially making the regeneration question less urgent for future generations.

Predicting Who Still Has Functioning Beta Cells

Not everyone with type 1 diabetes retains the same amount of residual beta cell function, and identifying who still has working cells matters for deciding who might benefit most from preservation therapies. Age at diagnosis is one of the strongest predictors: people diagnosed as adults tend to retain more beta cell function than those diagnosed as young children. Duration of disease matters too, though as the Joslin Medalist data showed, some people retain detectable function even after fifty years.

C-peptide measurement remains the standard clinical tool, but researchers are also looking at the ratio of proinsulin to C-peptide as an earlier indicator of beta cell stress. In a cohort of autoantibody-positive relatives of people with type 1 diabetes, elevated proinsulin-to-C-peptide ratios showed up roughly a year before clinical diagnosis, with the most pronounced elevations in children under ten.³⁰ Better biomarkers could eventually identify the people whose beta cells are struggling but still alive, allowing doctors to intervene before those cells are lost entirely.