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White mulberry (Morus alba) is a tree whose leaves have fed silkworms for thousands of years and are now sold as tea, powder and mulberry leaf extract capsules. The leaves contain 1-deoxynojirimycin (DNJ), a compound that slows the enzymes that break down starch and sugar in the gut. In small controlled studies, taking white mulberry leaf with a carbohydrate meal blunted the rise in blood sugar afterward. Reviews find the evidence for longer-term markers such as HbA1c weaker and mixed. People who take diabetes medicines need to talk to a clinician first, because the effects can add up.
Peptide Labs does not sell white mulberry products, and none of the supplements in our store lists it on the label. This article is general information, not medical advice.
Key Takeaways
- White mulberry leaf contains DNJ, which slows carbohydrate digestion in the gut.
- Small crossover trials found a smaller blood sugar rise after a carb drink or meal.
- A 2017 meta-analysis found lower after-meal glucose but no change in fasting glucose or HbA1c.
- A 2023 meta-analysis did report small drops in fasting glucose and HbA1c; study quality varies.
- Taking it with diabetes medicines may raise the risk of low blood sugar.
- Not enough is known about use in pregnancy or breastfeeding.
What is white mulberry?
Morus alba is native to China and has been grown across Asia, Europe and the Americas for silk production and for its fruit. Despite the name, its berries can ripen white, pink or nearly black. Supplements almost always use the leaf, while the fruit is eaten fresh, dried or in jams. Black mulberry (Morus nigra) and red mulberry (Morus rubra) are different species.
The leaf is the part studied for blood sugar. Its main compound of interest, DNJ, is a sugar-like molecule that inhibits alpha-glucosidase, the gut enzyme that splits sugars and starches into glucose. Prescription diabetes drugs such as acarbose and miglitol work through the same enzyme class. Leaves also contain flavonoids, other phenolic compounds and polysaccharides.
White mulberry benefits: the blood sugar research
Most white mulberry benefits discussed online relate to blood sugar. Here is a plain summary of the better-known human studies. They are research findings, not proof that a supplement manages any condition.
| Study | Who took part | What was tested | Main finding |
|---|---|---|---|
| Lown 2017, PLoS One | 37 healthy adults | Mulberry leaf extract vs placebo with a carb drink | Glucose rise about 14% to 22% lower at the two higher amounts |
| Phimarn 2017 meta-analysis | 13 randomized trials | Morus alba products vs control | Lower after-meal glucose; no change in fasting glucose, HbA1c or lipids |
| Jeong 2022 systematic review | Randomized trials | Morus alba for blood sugar | Lower after-meal glucose and insulin; evidence insufficient overall |
| Cui 2023 meta-analysis | 12 trials, 615 adults | Leaf or mulberry leaf extract | Small drops in fasting glucose, HbA1c and insulin |
| Shinkawa 2025, Nutrients | 31 adults | Two weeks of mulberry leaf blend tea vs placebo | Less glucose variability on CGM; no rise in low readings |
- After-meal glucose. The most consistent finding is a smaller blood sugar spike when white mulberry leaf is taken with carbohydrates. In the 2017 Lown crossover trial, healthy adults drank a maltodextrin solution with an extract or placebo; the two higher amounts cut the glucose rise by about 14% and 22%, and insulin rose less. One author worked for the company that makes the extract, and the study was funded by a UK government innovation grant.
- Longer-term markers. The 2017 meta-analysis of 13 randomized trials found no difference in fasting glucose, HbA1c, insulin resistance or cholesterol. A 2023 meta-analysis of 12 trials reported small reductions in fasting glucose and HbA1c, mainly in people with raised glucose who used it for at least eight weeks. A 2022 review concluded that the evidence is not yet enough to call it effective for lowering blood glucose.
- Twig alkaloid tablets. A standardized mulberry twig alkaloid tablet has been tested in Chinese trials in adults with type 2 diabetes; in one 16-week trial of 200 people, HbA1c fell more than with placebo, and digestive side effects were more common. That is a pharmaceutical product, not the leaf powder sold as a supplement.
- Combination products. Many capsules mix white mulberry with berberine, chromium or cinnamon. A 2026 trial of one such blend had no single-ingredient groups, so it cannot show what the mulberry itself did.
The honest summary: white mulberry leaf can soften the blood sugar rise after a starchy or sugary meal in short studies, and evidence beyond that is limited and mixed. If you are working on after-meal blood sugar, food choices matter more; our guides to sugar cravings and the GLP-1 diet cover practical eating patterns. If your glucose readings are high, see a clinician rather than self-managing with a supplement.
White mulberry leaf vs other carb-focused supplements
White mulberry leaf is often compared with other supplements marketed around carbohydrates. White kidney bean extract targets alpha-amylase, an earlier step in starch digestion. Gymnema blocks sweet taste on the tongue. Berberine, cinnamon and chromium act through other pathways. None of these replaces prescribed care, and stacking several of them makes the effect on your blood sugar harder to predict.
Side effects and who should be careful
In the short trials, white mulberry leaf was generally well tolerated. In the Lown trial there were no significant differences in nausea, cramping, bloating or gas between the extract and placebo. Because DNJ leaves more carbohydrate undigested, gas and bloating are plausible in some people; a 2007 study measured breath hydrogen, a marker of carbohydrate reaching the colon, for exactly that reason. Safety data beyond a few months are limited.
- Diabetes medicines. Monographs rate the interaction with diabetes drugs as moderate: combined with insulin, sulfonylureas or other glucose-lowering medicines, white mulberry might push blood sugar too low. Talk to your prescriber before trying it and watch for signs of low blood sugar.
- Pregnancy and breastfeeding. Not enough is known; the usual advice is to avoid it.
- Surgery. Because it can affect blood sugar, tell your surgical team about any supplement you take.
- Past reactions. If you have reacted to mulberry fruit or tea before, ask before trying the leaf.
- Quality. Extracts are not all standardized the same way, and supplements are not approved before sale. Our third-party testing guide explains what independent seals check.
Mulberry fruit nutrition
The fruit is a separate story from the leaf. USDA FoodData Central lists raw mulberries (FDC 169913, species not specified). Per 1-cup serving of 140 grams, they provide the following, with percent Daily Values from the FDA label values.
| Nutrient (raw mulberries) | Per 1 cup (140 g) | % Daily Value |
|---|---|---|
| Calories | 60 | Not applicable |
| Carbohydrate | 13.7 g | 5% |
| Fiber | 2.4 g | 8% |
| Sugars | 11.3 g | Not set |
| Protein | 2.0 g | 4% |
| Vitamin C | 51 milligrams | 57% |
| Iron | 2.6 milligrams | 14% |
| Potassium | 272 milligrams | 6% |
| Magnesium | 25 milligrams | 6% |
In this USDA entry, mulberries are a good fruit source of vitamin C and also supply some iron. The fruit does not carry the leaf’s DNJ research, so fruit products should not be marketed with leaf study results. For a marine food with a very different evidence picture, see our sibling guide to sea cucumber.
Frequently Asked Questions
What is white mulberry used for?
White mulberry leaf is mostly sold for after-meal blood sugar support. The fruit is eaten as food and is rich in vitamin C.
Does mulberry leaf extract lower blood sugar?
In small studies it blunted the blood sugar rise after carbohydrates. Effects on fasting glucose and HbA1c are mixed across reviews.
What are the main white mulberry benefits in research?
The most consistent finding is a smaller glucose and insulin rise after a carb-containing meal or drink in short trials.
Can I take white mulberry leaf with metformin or insulin?
Only with your prescriber’s input. Combining it with diabetes medicines may raise the risk of low blood sugar.
What are the side effects of Morus alba?
Short trials reported few side effects. Gas or bloating is possible because more carbohydrate reaches the colon. Long-term data are limited.
Is white mulberry safe in pregnancy?
Not enough is known, so the usual advice is to avoid it while pregnant or breastfeeding.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Bitter Melon: Nutrition, Blood Sugar Research and Side Effects, Berberine Benefits: What the Research Shows and What It Does Not, Low Glycemic Foods: Glycemic Index Chart and Glycemic Load Explained.