By goal
Evidence-Backed Supplements for Blood Sugar and Metabolic Health
Some supplements have randomized-trial evidence for modest effects on fasting glucose, HbA1c, or insulin sensitivity, while many popular blood sugar support products have little or no support. This hub grades each option by the strength of the evidence so you can see what holds up. Nothing here treats or cures diabetes or replaces prescribed medication.
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Best-supported here: Berberine (Moderate), Garlic (Moderate), Nicotinamide Riboside (NR) (Preliminary), NMN (Nicotinamide Mononucleotide) (Preliminary) — each graded below by the weight of human evidence.
| Supplement | Evidence for this goal | Typical dose | Key caution | Studies |
|---|---|---|---|---|
| Berberine | Strong for this goal | 500 mg, 2–3× daily with meals (1,000–1,500 mg/day total). | Common GI upset and cramping. | 18 |
| Garlic | Strong for this goal | Garlic powder 300-900 mg/day (standardized to ~1.8-5.4 mg allicin), or… | Garlic is safe as a food, but supplemental doses can cause breath and body odor, heartburn,… | 21 |
| Nicotinamide Riboside (NR) | Strong for this goal | 250–1000 mg/day orally (trials have used up to 2000–3000 mg/day); commo… | Generally well tolerated; most common adverse effects are mild headache, flushing or feelin… | 16 |
| NMN (Nicotinamide Mononucleotide) | Strong for this goal | 250–600 mg once daily by mouth; trials have used up to 900 mg/day. Bloo… | Short-term oral NMN (up to 900 mg/day for 1-3 months) was well tolerated in trials, with no… | 12 |
| Omega-3 (EPA/DHA) | Strong | 1–2 g combined EPA+DHA/day; up to 4 g (Rx) for high triglycerides. | Safe at typical doses. | 20 |
| Alpha-Lipoic Acid | Moderate for this goal | Oral: 300-600 mg/day (commonly 600 mg, often divided and taken on an em… | Generally well tolerated; the most common side effects are mild gastrointestinal upset (nau… | 19 |
| Apple | Moderate | One medium apple (~182 g) per day, eaten whole with skin where most pol… | Generally very safe. | 9 |
| Ashwagandha | Moderate | 300–600 mg/day of root extract (standardized to 5% withanolides), often… | Avoid in pregnancy (traditionally abortifacient) and while breastfeeding. | 18 |
| Banana | Moderate | 1 medium banana (about 118 g edible) provides roughly 105 kcal and 422… | Generally very safe. | 9 |
| Blackberry | Moderate | A common serving is 1 cup (about 144 g, ~62 kcal). Dietary patterns and… | Generally very safe as a whole food. | 11 |
| Blackcurrant | Moderate | About 1 cup fresh berries (110-150 g); ergogenic/eye-health trials use… | Generally safe as food. | 10 |
| Blueberry | Moderate | A typical serving is 1 cup (148 g) of fresh berries; trials showing vas… | Generally very safe as a food. | 8 |
| Cranberry | Moderate | A standard culinary serving is about 1 cup (100 g) of fresh raw berries… | Generally safe as a food. | 8 |
| Curcumin (Turmeric) | Moderate | 500–1,000 mg curcuminoids/day; bioavailability-enhanced forms preferred. | Generally safe. | 23 |
| Guava | Moderate | One to two whole fruits daily (about 55-165 g) as part of a varied diet… | Generally safe as a food. | 6 |
| Inositol (Myo-Inositol) | Moderate | PCOS: typically 2 g myo-inositol twice daily (4 g/day), often with 400… | Generally well tolerated; the most common side effects are mild, dose-related gastrointesti… | 14 |
| Kiwifruit | Moderate | Two green kiwifruit daily (about 140-180 g) is the dose used in most co… | Kiwifruit is a recognised allergen and can cause oral allergy syndrome or, rarely, anaphyla… | 8 |
| Lemon | Moderate | 1 medium lemon (~58 g) or 2-4 oz juice daily; lemonade therapy uses ~4… | High acidity can erode dental enamel and aggravate GERD or mouth ulcers; rinse with water a… | 10 |
| Magnesium | Moderate for this goal | 200–400 mg elemental/day. Glycinate & citrate absorb best; oxide is poo… | Safe. | 20 |
| Mandarin Orange | Moderate | One medium mandarin (~88 g) provides roughly a quarter of the vitamin C… | Generally very safe and well tolerated. | 9 |
| Mulberry | Moderate | 1 cup fresh fruit (~140 g); glycemic trials use mulberry-leaf extract s… | Generally recognized as safe as a food. | 8 |
| Olives | Moderate | About 15 g (4-5 medium olives) as a typical serving; Mediterranean-diet… | High sodium is the main concern—brined/canned olives can carry roughly 700-900 mg sodium pe… | 9 |
| Orange | Moderate | One medium orange (~131 g) provides ~77% of the vitamin C Daily Value;… | Generally very safe. | 10 |
| Pear | Moderate | One medium pear (~178 g) provides ~5.5 g fibre, roughly a fifth of the… | Generally very safe. | 8 |
| Plantain | Moderate | 1 medium plantain (~179 g); culinary staple eaten cooked — boiled, frie… | Generally safe as a food. | 8 |
| Prune (Dried Plum) | Moderate | Typical serving 4-5 prunes (~40-50 g) daily. For constipation, RCTs use… | High in sorbitol and fibre, so larger amounts can cause bloating, gas, cramping or diarrhoe… | 9 |
| Red Grape | Moderate | A typical serving is about 1 cup (~150 g, ~17 grapes); intervention tri… | High in free sugars (~23 g per cup) and easy to overeat, so portion control matters for gly… | 10 |
| Resveratrol | Moderate for this goal | Commonly 150–500 mg/day of trans-resveratrol; research doses range up t… | Generally well tolerated up to about 1,000 mg/day; higher doses (>=1,000–2,000 mg/day) freq… | 23 |
| Spirulina | Moderate for this goal | Commonly 1-8 g/day (some trials up to ~10 g/day) of dried Arthrospira,… | Generally well tolerated short-term; mild GI upset, headache, or allergic-type reactions ca… | 16 |
| Strawberry | Moderate | A typical serving is about 1 cup (152 g, ~8 medium berries) fresh. Card… | Generally very safe. | 10 |
| Watermelon | Moderate | A typical serving is one wedge (~286 g) or 1-2 cups of diced flesh; car… | Generally very safe as a food. | 8 |
| Acai Berry | Preliminary | Commonly eaten as 100 g (about half a 200 g pack) of unsweetened frozen… | Generally well tolerated as a food. | 7 |
| Ambarella | Preliminary | One medium fruit (about 60-100 g) eaten fresh, or 100-150 g in juice or… | Generally safe as a food. | 8 |
| Amla (Indian Gooseberry) | Preliminary for this goal | ~500 mg of extract once or twice daily. | Generally safe as a food. | 13 |
| Apricot | Preliminary | 1 cup halves (155 g) fresh, ~2-3 whole apricots; or ~30-40 g dried (a s… | The flesh is very safe. | 9 |
| Bilimbi | Preliminary | A few fruits (~5–50 g) used as a souring agent in cooking; no establish… | Extremely high oxalic-acid content: laboratory analyses report roughly 8.5–14.7 mg/g (≈850–… | 10 |
| Breadfruit | Preliminary | 1 cup cooked cubes (~220 g) as a starch staple in place of rice, potato… | Generally safe as a food. | 10 |
| Calamansi | Preliminary | 2–4 fruits' juice (about 15–30 mL) as a souring agent, or ~100 g whole… | Highly acidic—erosive to tooth enamel and may aggravate GERD, reflux or mouth ulcers; dilut… | 9 |
| Cempedak | Preliminary | 1 serving of fresh pulp, roughly 100 g (about 4-6 arils) | Cempedak is a high-carbohydrate, moderate-energy fruit (~117 kcal/100 g) and can raise bloo… | 10 |
| Dates | Preliminary | Typical serving 2 Medjool dates (~48 g); 3 dates/day used in glycemic a… | Very high sugar and energy density (~133 kcal per 2 dates) — portion control matters for we… | 9 |
| Dragon Fruit (Pitaya) | Preliminary | 1 medium fruit (~200-230 g) fresh pulp daily; the vascular trial used ~… | Generally safe as a food. | 9 |
| Durian | Preliminary | Roughly 1-2 segments (~40-100 g pulp); a portion delivering 50 g carboh… | Energy- and fat-dense for a fruit (~147 kcal and 5 g fat per 100 g), so large portions add… | 10 |
| Fig | Preliminary | A typical serving is 2 medium fresh figs (about 100 g) or 3-4 dried fig… | Figs are high in natural sugars (especially dried), so portion-control matters for diabetes… | 10 |
| Gandaria | Preliminary | Culinary fruit; ~100 g (a small handful of 3–5 fruits) as a typical ser… | Generally safe as a food; rodent toxicity studies of fruit-extract yoghurt showed no advers… | 9 |
| Ginger | Preliminary for this goal | 1–1.5 g/day of dried ginger powder in divided doses (typically 250 mg,… | Generally well tolerated at culinary and supplemental doses; the most common side effects a… | 18 |
| Honeydew Melon | Preliminary | 1 cup diced (~170 g); a typical wedge is one-eighth of a medium melon | Generally very safe. | 9 |
| Indian Jujube (Ber) | Preliminary | A typical serving is about 3 fresh fruits (~100 g), providing roughly 6… | Generally recognized as safe as a food. | 9 |
| Jackfruit | Preliminary | About 1 cup sliced (165 g) of raw ripe fruit; the clinical glycemic tri… | Generally recognized as safe as a food. | 9 |
| Jambolan (Jamun / Java Plum) | Preliminary | Culinary: ~100-135 g fresh fruit (1 cup). Studied antidiabetic preparat… | Generally safe as a food. | 9 |
| Longan | Preliminary | About 1 cup of fresh pitted pulp (~96 g, roughly 20-30 fruits); dried l… | Generally safe as a food. | 8 |
| Lychee | Preliminary | About 9 fresh lychees (~100 g edible flesh); Oligonol trials used 100-2… | Generally safe as a food in normal amounts. | 11 |
| Mango | Preliminary | A typical serving is about 1 cup of pieces (165 g) or roughly half a me… | Generally safe as a food. | 8 |
| Mangosteen | Preliminary | 1 medium fruit (~3-4 segments of edible aril, ~40-60 g flesh); studied… | The fresh aril is generally safe as a food. | 9 |
| Nectarine | Preliminary | A typical serving is 1 medium nectarine (about 140-150 g), eaten fresh… | Nectarines are a stone fruit (Prunus/Rosaceae); people with birch-pollen or oral allergy sy… | 9 |
| Passion Fruit | Preliminary | Pulp of 2-3 fruits (~36-55 g edible) as a whole-food serving. Studied b… | Generally safe as a food. | 9 |
| Persimmon | Preliminary | 1 medium fresh fruit (~168 g); persimmon-extract supplement trials used… | Astringent/unripe persimmons are high in soluble tannins that can polymerize in stomach aci… | 10 |
| Psyllium (Fiber) | Preliminary for this goal | For cholesterol/heart health: ~7 g/day of soluble fiber (about 10.2 g o… | Generally safe and well tolerated; the most common side effects are bloating, flatulence, a… | 10 |
| Pulasan | Preliminary | 1–3 fresh fruits (~50–150 g edible aril); no studied therapeutic dose | Generally regarded as a safe edible fruit with no documented toxicity or drug interactions. | 11 |
| Raspberry | Preliminary | A typical serving is 1 cup (~123 g) of fresh or frozen raspberries; cli… | Generally very safe as a food. | 11 |
| Red Yeast Rice | Preliminary for this goal | Studied at 200-4,800 mg/day of RYR powder, standardized to monacolin K.… | Because monacolin K IS a statin (lovastatin), red yeast rice carries statin-class risks and… | 12 |
| Salak (Snake Fruit) | Preliminary | 1-3 fresh fruits (~50-150 g edible flesh) as a snack; no established th… | Generally safe as a food. | 10 |
| Santol | Preliminary | 1 medium fruit (~100 g edible flesh); traditional use is as fresh fruit… | The hard seeds are indigestible and have caused intestinal obstruction, perforation, and ab… | 8 |
| Sapodilla (Ciku) | Preliminary | 1 medium fruit (~170 g); ~100-170 g fresh ripe pulp | Unripe fruit is high in astringent tannins and latex that can cause mouth irritation, throa… | 9 |
| Sugar Apple (Custard Apple) | Preliminary | 1 medium fruit (about 155 g edible pulp); the seeds, peel, leaves and r… | Never eat or chew the seeds, and avoid leaf, bark and root preparations: they are concentra… | 10 |
| Tamarind | Preliminary | Culinary: about 10-30 g of pulp per day (paste, juice, or chutney). Car… | Generally recognized as safe as a food. | 10 |
| Wax Apple | Preliminary | 1-2 fresh fruits (~85-170 g); eaten raw, skin-on | Generally recognized as safe as a food and well tolerated when eaten fresh. | 8 |
| Apple Cider Vinegar | Mixed | Commonly studied at 10-30 mL/day (about 1-2 tablespoons) of ~5% liquid… | Always dilute in water and avoid drinking it straight — undiluted vinegar (pH ~3) causes de… | 17 |
| Cinnamon | Mixed for this goal | 1–2 g/day of cinnamon powder or standardized extract in divided doses;… | Generally safe as a food/spice. | 19 |
| Green Tea Extract (EGCG) | Mixed for this goal | Commonly 250-500 mg/day of standardized extract providing roughly 100-3… | Concentrated green tea EXTRACTS (unlike ordinary brewed tea) carry a rare but documented ri… | 19 |
| Peach | Mixed | 1-2 medium fresh peaches (about 150-300 g) as a serving; whole fruit is… | Generally very safe as a whole fruit. | 9 |
| Vitamin D3 | Mixed for this goal | 1,000–2,000 IU/day maintenance; higher to correct deficiency under test… | Tolerable upper limit ~4,000 IU/day for most adults; toxicity (hypercalcemia) occurs with c… | 16 |
| Garcinia Cambogia (HCA) | No Evidence | Not recommended — benefits are negligible and liver-safety concerns exi… | ⚠ Liver injury (hepatotoxicity) has been reported with HCA-containing products, sometimes s… | 13 |