Supplements · Metabolic & Cardiometabolic
mulberry leaf (1-deoxynojirimycin) decreases postprandial glucose
In plain terms: Does mulberry-leaf extract lower blood-sugar spikes?
Small RCTs (often industry-linked) show acute postprandial glucose reduction, strongest in impaired-glucose subjects; evidence is positive but low-to-moderate quality.
📅 Last reviewed: 2026-07-14 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
What the evidence shows
Mulberry-leaf DNJ blunts postprandial glucose/insulin via intestinal alpha-glucosidase inhibition (acarbose-like) at low dose — mechanistically ideal for a starchy bread, but thermal survival through baking is the critical unproven gate.
The evidence (16)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Shinkawa Y et al] # corrected 2026-08-17 from PubMed; was [(mulberry+water-chestnut) 2025 · (RCT crossover) | RCT | supports | moderate | RCT crossover n=31 CGM DNJ tea lowered glucose CV p=.0006 + 1h AUC. Tea not bread - bake-stability unproven |
| Cui 2023 · Food Funct | meta-analysis | supports | moderate | Meta-analysis of 12 RCTs (615 subjects): mulberry leaf/extract significantly reduced fasting blood glucose and HbA1c. |
| Thaipitakwong 2020 · Complement Ther Med | RCT | supports | moderate | Dose-finding RCT: DNJ-standardized mulberry leaf improved glycemic profile in borderline-diabetic obese adults. |
| Lown 2017 · PLoS One | RCT | supports | moderate | Mulberry extract improved glucose tolerance and lowered insulin in normoglycemic adults; industry-supported, small n. |
| Kwon 2011 · J Agric Food Chem | animal | mixed | moderate | Whole mulberry extract lowered glucose response in rats, but isolated DNJ alone did not inhibit Caco-2 glucose uptake. |
| Dong 2020 · J Agric Food Chem | in-vitro | supports | moderate | DNJ inhibited maltase-glucoamylase and lowered postprandial glucose in mice; synergistic with flavonoids. |
| Thondre 2024 · Nutrients | RCT | supports | moderate | Reducose mulberry leaf extract dose-dependently lowered postprandial glucose and insulin responses in healthy adults. |
| Kojima 2010 · J Clin Biochem Nutr | observational | tested-null | low | DNJ-rich mulberry extract before meals modestly improved lipid profile; supports glucosidase-inhibition mechanism, glucose secondary. |
| (MLAE RCT) 2015 · (RCT) | RCT | supports | moderate | RCT n=36 prediabetic MLAE 5g/d attenuated postprandial glucose/insulin; lower insulin iAUC p=.02 |
| Yu JT 2025 · Int J Mol Sci | meta-analysis | supports | moderate | Meta-analysis of 15 RCTs (1202 participants) found mulberry extract improved fasting glucose, HbA1c, HOMA-IR, and lipids; subgroup analysis showed greater benefit at shorter duration and doses <500 mg/day. |
| Mohamed M 2023 · Diabetes Ther | RCT | supports | high | Randomized placebo-controlled crossover in 30 T2D adults: a 250mg MLE (12.5mg DNJ) blend reduced postprandial glucose iAUC by 20% (1h), 17% (2h), 15% (3h) and Cmax by 0.8 mmol/L (p<0.01 for all), with reduced 1h insulin iAUC, cons |
| (DNJ RCT) 2007 · (RCT) | RCT | supports | moderate | HUMAN DNJ 0.8-1.2g suppressed postprandial glucose+insulin after sucrose |
| Asai 2011 · J Diabetes Investig | RCT | supports | moderate | DNJ-enriched mulberry leaf extract suppressed postprandial hyperglycemia in subjects with impaired glucose metabolism. ↩ SUPERSEDED — pooled in the review above, counted once |
| Kume 2025 · J Nutr Sci Vitaminol | RCT | supports | low | Powdered Morus australis leaf lowered glucose 30 min post-sucrose and prevented post-meal arterial stiffening in young men. |
| Wang 2018 · Medicine (Baltimore) | RCT | supports | low | Mulberry leaf extract (DNJ) reduced glycemic indexes of four common dietary carbohydrates in humans. |
| Mela DJ 2024 · Nutrients | RCT | supports | moderate | Randomized crossover pilot in 24 T2D adults: 0.37g and 0.75g mulberry fruit extract added to carb-rich meals reduced 2hr postprandial glucose iAUC by 8.2% and 22.4%, and postprandial insulin by 9.6% and 17.5% respectively, dose-de |
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