Mulberries contain compounds that may lower blood sugar and support heart health, but most evidence comes from lab and animal studies rather than human trials

Mulberries—the dark purple berries from Morus trees—contain several compounds that researchers have studied for metabolic effects. The main ones are anthocyanins (the pigments that make them dark), resveratrol (also found in grapes), and 1-deoxynojirimycin (a compound that slows sugar digestion). In animal models and lab dishes, these compounds show activity against inflammation, oxidative stress, and glucose spikes. What remains unclear is how much of that activity translates to humans eating whole mulberries, and at what dose.

The gap between "shows promise in mice" and "works in people" is real and worth understanding. A handful of small human studies exist, mostly from Asia where mulberry cultivation is older and research funding more available. They suggest modest effects on blood sugar control and cholesterol in people with prediabetes or metabolic syndrome. But the studies are small, often lack a true control group, and don't yet tell us whether eating mulberries regularly produces the same results as taking a concentrated extract in a lab setting.

Key Takeaways

  • Mulberries contain anthocyanins and other compounds that slow sugar absorption in lab studies and animal models, but human evidence is limited to small trials with modest results.
  • Most research on mulberry extracts shows effects on blood sugar and cholesterol, not on weight loss or disease prevention in otherwise healthy people.
  • Whole mulberries contain fiber and are low in calories, making them a reasonable fruit choice, but they are not a substitute for medication or dietary change in people with diabetes.
  • Mulberry leaf tea has been studied separately from the fruit and shows different compounds; research on leaves is even more limited than research on berries.

How mulberries affect blood sugar in the body

The compound 1-deoxynojirimycin (DNJ) in mulberries works by slowing the enzymes that break down complex carbohydrates in your small intestine. In theory, this means glucose enters your bloodstream more gradually, producing a smaller spike after a meal. This mechanism has been demonstrated in test tubes and in mice fed high-sugar diets.

In human studies, the effect is real but modest. A 2015 trial published in Nutrition & Metabolism found that people with prediabetes who consumed mulberry leaf extract before meals showed a 10 to 15 percent reduction in post-meal blood sugar compared to placebo. A smaller 2009 study in Diabetes Care reported similar findings. However, these studies used concentrated extracts—not whole berries—and involved only 20 to 40 participants each. Neither study tracked whether the effect persisted over months or years, or whether it mattered if people also changed their diet or exercise habits.

For people taking diabetes medication, the practical question is whether eating mulberries could reduce the need for drugs. The research does not support that claim. Mulberries may help blunt a blood sugar spike from a meal, but they do not replace insulin or metformin, and no study has shown they reduce HbA1c (the three-month average blood sugar marker) as effectively as medication does.

Anthocyanins and heart health: what the evidence shows

Mulberries are rich in anthocyanins, water-soluble pigments that act as antioxidants. In lab dishes, anthocyanins reduce oxidative stress and inflammation—two processes linked to atherosclerosis and heart disease. Animal studies show that anthocyanin-rich diets can lower cholesterol and reduce plaque buildup in arteries.

Human evidence is thinner. A 2016 study in Phytotherapy Research gave mulberry extract to 40 people with high cholesterol for 12 weeks and found small reductions in LDL cholesterol and triglycerides compared to placebo. A 2013 Iranian trial reported similar results. But these studies are small, lasted only weeks to months, and did not track whether the effect prevented heart attacks or strokes—the outcomes that actually matter for heart health.

The broader context matters: anthocyanins are found in many berries (blueberries, blackberries, raspberries) and in red wine, pomegranate, and dark chocolate. If you already eat other anthocyanin-rich foods, adding mulberries may not provide additional benefit. If you don't, mulberries are one option among many, not a unique source.

Mulberry leaf tea versus the fruit: different compounds, different research

Mulberry leaf tea is often marketed separately from the fruit, and the research is distinct. Leaves contain higher concentrations of DNJ and different polyphenols than berries do. Several Asian studies have examined mulberry leaf extract for blood sugar control, and the results are similar to fruit studies—modest effects in small trials, no long-term data.

One 2013 meta-analysis in Nutrition Reviews pooled 20 studies on mulberry leaf extract and concluded that the evidence for blood sugar reduction was "promising but not conclusive." The authors noted that study quality was often poor, sample sizes were small, and publication bias (the tendency for positive results to be published more often) was likely.

If you enjoy mulberry leaf tea, it is a low-risk beverage with no known serious side effects at typical doses. But treating it as a medical intervention—a substitute for diet change or medication—is not supported by the evidence.

Fiber, calories, and mulberries as a whole food

Setting aside the bioactive compounds, mulberries are straightforward a fruit: low in calories (about 60 per 100 grams), moderate in fiber (about 1.7 grams per 100 grams), and high in water. They contain vitamin C, iron, and potassium in small amounts. From a nutritional standpoint, they are comparable to blackberries or raspberries.

The fiber content is worth noting. Soluble fiber slows digestion and can help stabilize blood sugar—not because of a special compound, but because of basic physiology. If you eat mulberries whole (not as juice or extract), you get that fiber benefit. If you drink mulberry juice or take a supplement, you lose most of the fiber and concentrate the sugars.

For someone trying to manage blood sugar or weight, whole mulberries are a reasonable choice. They are not a weight-loss food or a diabetes cure, but they are less calorie-dense and more filling than many other fruits, and the fiber helps. The research on the fruit itself—not extracts—is limited, but eating whole mulberries as part of a varied diet is unlikely to cause harm.

What the research gap means for your choices

The honest summary: mulberries contain compounds that show activity in lab and animal models, and small human studies suggest modest effects on blood sugar and cholesterol. But we do not have large, long-term trials in humans, we do not know the optimal dose, and we do not know whether the effects persist or matter for real health outcomes like preventing diabetes or heart disease.

This is not unusual for plant foods. Most fruits and vegetables have not been tested in large randomized trials because funding for such studies is limited and the financial incentive is low. It does not mean mulberries are useless; it means the evidence is preliminary.

If you have prediabetes or high cholesterol and are considering mulberries as part of your diet, talk with your doctor or a registered dietitian. They can help you weigh mulberries against other dietary changes—like reducing refined carbohydrates, increasing vegetables, or moving more—that have stronger evidence. If you take diabetes or cholesterol medication, do not reduce your dose based on eating mulberries without medical guidance.

Frequently Asked Questions

Do mulberries have more anthocyanins than blueberries?

Mulberries and blueberries have similar anthocyanin content, though the exact amount varies by variety and growing conditions. Neither has been shown to be dramatically superior for health outcomes. If you like one more than the other, that preference is a better reason to choose it than any minor difference in compound levels.

Can mulberry extract replace my diabetes medication?

No. Mulberry extract shows modest effects on blood sugar in small studies, but it is not a substitute for medication. If you are taking diabetes drugs and want to explore dietary changes, work with your doctor or a diabetes educator to make safe adjustments. Stopping or reducing medication without medical guidance can be dangerous.

Is mulberry leaf tea safe to drink every day?

Mulberry leaf tea is generally considered safe at typical doses and has no known serious side effects. However, if you take blood sugar medication or blood thinners, check with your doctor before drinking it regularly, as the compounds in mulberry leaves may interact with these drugs.

Where can I buy fresh or dried mulberries?

Fresh mulberries are seasonal and available in late spring or early summer at farmers markets in regions where mulberry trees grow. Dried mulberries are sold online and in some health food stores. Frozen mulberries are also available. Whole berries are preferable to juices or extracts if you want the fiber benefit.

Do mulberries help with weight loss?

Mulberries are low in calories and contain fiber, so they can fit into a weight-loss diet. But no study has shown that mulberries specifically cause weight loss. Weight loss comes from eating fewer calories overall and moving more; mulberries are one tool among many, not a weight-loss food on their own.