Bitter melon
Summary
Bitter melon is a tropical gourd used for blood sugar. Pooled trials disagree: one meta-analysis found a small HbA1c drop in type 2 diabetes on low-quality evidence, while another found no effect versus placebo (grade C). It slightly lowered total cholesterol and triglycerides but not weight. It can add to diabetes drugs and has caused low blood sugar in children.
Key facts
- Fruit of the Momordica charantia vine, eaten as a vegetable and used in traditional medicine for diabetes[10]
- Pooled results conflict: HbA1c −0.26 points in one meta-analysis (low quality) versus no significant effect in another[1][2]
- Insufficient evidence; no preparation was tested twice and risk of bias was generally high[8]
- 2,000 mg/day lowered fructosamine less than metformin 1,000 mg/day over 4 weeks[7]
- Not linked to liver-enzyme rises or clinically apparent liver injury[10]
- 6 graded human outcomes on this page
- October 13, 2026
How it works
ProposedComponents of bitter melon extract show structural similarity to animal insulin, and four small early trials reported a moderate glucose-lowering effect. The proposed mechanism has not been confirmed as the cause of glucose changes in people.[9]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Blood sugar | Grade C | Improved | Meta-analysis of 10 trials · n = 1,045 · 2019 | 4 rows |
| Weight | Grade C | No effect | Meta-analysis of 10 trials · n = 448 · 2024 | 1 row |
| Cholesterol | Grade C | Improved | Meta-analysis of 8 trials · n = 423 · 2024 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Fasting glucose and HbA1c in type 2 diabetes (pooled trials) | Improved | Grade C | Meta-analysis · n = 1,045 · 2019 Adults with type 2 diabetes, 4–16 weeks of follow-up Form: Single-herb bitter melon preparations (fruit, juice, powder or extract) · Dose: Varied across trials · Duration: 4–16 weeks Versus placebo, fasting glucose fell 0.72 mmol/L, post-meal glucose 1.43 mmol/L and HbA1c 0.26 percentage points. The authors rated the evidence low to very low quality. | 30385422 (opens PubMed)Source [1] |
| Body weight, BMI, waist and body fat (pooled trials) | No effect | Grade C | Meta-analysis · n = 448 · 2024 Adults in clinical trials Form: Bitter melon supplements · Dose: Varied across trials · Duration: Varied No significant change in body weight, BMI, waist circumference or body-fat percentage. | 39079610 (opens PubMed)Source [4] |
| Total cholesterol and triglycerides (pooled RCTs) | Improved | Grade C | Meta-analysis · n = 423 · 2024 Adults in randomized trials, including people with diabetes or prediabetes Form: Bitter melon supplements · Dose: Varied; subgroup effects at ≤2,000 mg/day · Duration: Under 3 months Total cholesterol fell 9.71 mg/dL and triglycerides 10.24 mg/dL; LDL and HDL did not change significantly. | 39444254 (opens PubMed)Source [3] |
| Fasting glucose, HbA1c, lipids and blood pressure (placebo-controlled trials) | No effect | Grade C | Meta-analysis · n = 414 · 2023 Adults in trials of metabolic syndrome measures Form: Bitter melon preparations · Dose: Varied across trials · Duration: 4–16 weeks No significant effect versus placebo on fasting glucose (−0.03 mmol/L), HbA1c (−0.12 points), LDL, HDL, total cholesterol, weight or blood pressure. Liver and kidney markers did not change. | 38274207 (opens PubMed)Source [2] |
| HbA1c and fasting glucose in type 2 diabetes (bitter melon extract) | Mixed | Grade D | RCT · n = 90 · 2020 Adults with type 2 diabetes (bitter melon as add-on treatment) Form: Bitter melon extract · Dose: Dose not stated in the abstract · Duration: 12 weeks HbA1c did not change in either group; fasting glucose fell within the bitter melon group (P=0.014). No serious adverse events. | 32951763 (opens PubMed)Source [5] |
| Fasting glucose and insulin resistance in prediabetes (freeze-dried fruit) | Improved | Grade D | RCT · n = 38 · 2025 Adults with prediabetes Form: Freeze-dried whole bitter gourd fruit (cucumber-based control) · Dose: 3.6 g/day · Duration: 12 weeks Fasting glucose and HOMA-IR improved versus control (P=0.026 and P=0.045). A separate 4-week crossover with 2.4 g/day freeze-dried juice in 30 people found no difference. | 40199408 (opens PubMed)Source [6] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Dried fruit powder or capsules | Varies[1][7] | No human absorption study was found; trials measured blood-sugar outcomes directly.[1][7] | No serious adverse effects were reported in the pooled trials.[1][2] | Type 2 diabetes and prediabetes trials (500–3,600 mg/day) |
| Standardized fruit extracts | Varies[8] | Not characterized in the cited trials; preparations varied so much that the Cochrane review found no preparation tested twice.[8] | No serious adverse events over 12 weeks in a 90-person trial.[5] | Type 2 diabetes (12 weeks) |
| Juice or cooked vegetable | Varies[9] | Not studied for absorption.[9] | Hypoglycemic coma and convulsions have been reported in children given bitter melon tea or juice.[9] | Early uncontrolled glucose studies |
Studied doses
Doses studied in human trials ranged from 500 to 2,000 mg/day of dried bitter melon in a 4-week trial against metformin up to 3.6 g/day of freeze-dried whole fruit for 12 weeks in prediabetes; pooled trials lasted 4 to 16 weeks.[7][6][1][2]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Glucose-lowering medicinesReviewBitter melon may have additive blood-sugar-lowering effects with other glucose-lowering agents.[9]
Who should be careful
- Children
- Hypoglycemic coma and convulsions have been reported in children given bitter melon.[9]
- G6PD deficiency
- A favism-like reaction has been reported with bitter melon.[9]
- Pregnancy or trying to conceive
- No human safety data; reduced fertility was seen in mice.[9]
- People on diabetes medicines
- Effects may add to glucose-lowering drugs, so monitoring is needed.[9]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
- Preparation variesTrials used juice, dried fruit, powder and extracts; the Cochrane review found no preparation tested twice, so results from one product may not apply to another.[8]
- Label dose vs studied doseOnly the 2,000 mg/day arm lowered fructosamine in the trial against metformin; 500 and 1,000 mg/day did not.[7]
Cost per studied dose, without the sales pitch
Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.
Cost per studied dose
Enter the price, servings and the amount per serving from your label.
Frequently asked questions
Does bitter melon lower blood sugar?
Possibly a little. One meta-analysis of 10 studies found HbA1c fell 0.26 points in type 2 diabetes on low-quality evidence; another of 9 placebo-controlled trials found no significant effect.[1][2]
Can bitter melon replace metformin?
No trial supports that. In a 4-week head-to-head trial, 2,000 mg/day lowered fructosamine less than metformin 1,000 mg/day.[7]
Does bitter melon help weight loss?
No. A meta-analysis of 10 trials with 448 adults found no change in weight, BMI, waist or body fat.[4]
Is bitter melon safe?
Trials up to 16 weeks reported no serious adverse effects, and it is not linked to liver injury. It has caused low blood sugar in children and a favism-like reaction, and may add to diabetes drugs.[1][10][9]
Does bitter melon lower cholesterol?
Slightly. Pooled trials found total cholesterol fell about 10 mg/dL and triglycerides about 10 mg/dL, with no significant change in LDL or HDL.[3]
Sources
- [1]Momordica charantia L. lowers elevated glycaemia in type 2 diabetes mellitus patients: Systematic review and meta-analysis.. J Ethnopharmacol, 2019. meta-analysis
- [2]The metabolic effect of Momordica charantia cannot be determined based on the available clinical evidence: a systematic review and meta-analysis of randomized clinical trials.. Front Nutr, 2023. meta-analysis
- [3]The Effects of Bitter Melon ( Mormordica charantia ) on Lipid Profile: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Phytother Res, 2024. meta-analysis
- [4]The effects of bitter melon (Momordica charantia) on anthropometric indices in adults: A systematic review and meta-analysis of randomized controlled trials.. Prostaglandins Other Lipid Mediat, 2024. meta-analysis
- [5]Hypoglycemic efficacy and safety of Momordica charantia (bitter melon) in patients with type 2 diabetes mellitus.. Complement Ther Med, 2020. RCT
- [6]Bitter gourd (Momordica charantia L.) supplementation for twelve weeks improves biomarkers of glucose homeostasis in a prediabetic population.. J Ethnopharmacol, 2025. RCT
- [7]Hypoglycemic effect of bitter melon compared with metformin in newly diagnosed type 2 diabetes patients.. J Ethnopharmacol, 2011. RCT
- [8]Momordica charantia for type 2 diabetes mellitus.. Cochrane Database Syst Rev, 2012. systematic-review
- [9]Bitter melon (Momordica charantia): a review of efficacy and safety.. Am J Health Syst Pharm, 2003. review
- [10]Bitter Melon.. LiverTox (NIDDK), 2012. database
What changed
- Adversarial review pass: every evidence row's numbers re-checked against its abstract (Europe PMC for abstracts PubMed truncates, PMC full text where open), grades checked against the grading rubric, and safety and overclaim wording re-read. Fixes: Glucose meta-analysis row notes that the 1,045 total includes drug-comparison trials.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Strict second-pass self review (no separate reviewer agent was available for this batch): every PMID re-fetched via esummary and every evidence row, dose and safety line re-read against its abstract or fact sheet. No NIH ODS or NCCIH fact sheet covers bitter melon; LiverTox (updated 2023) and a 2003 safety review are used for safety. The two conflicting glucose meta-analyses are both shown. Retraction and erratum flags checked on all PMIDs: none.