Bitter Melon: Nutrition, Blood Sugar Research and Side Effects

Bitter melon (Momordica charantia), also called bitter gourd or karela, is a warty green vine fruit cooked as a vegetable across Asia, Africa, the Caribbean and South America. A cup of the raw pods has about 16 calories and close to the full Daily Value for vitamin C, according to USDA data. It is also a traditional remedy for high blood sugar, but the clinical evidence is mixed: some meta-analyses find small drops in glucose, others find no clear effect, and a Cochrane review called the evidence insufficient. Bitter melon also has more safety cautions than most vegetables, from pregnancy to diabetes medicines. Below are the USDA numbers, what the research shows, and who should avoid concentrated bitter melon products.

Peptide Labs does not sell bitter melon as a food; two supplement blends we carry list bitter melon extract, described below. This article is general nutrition information, not medical advice.

What is bitter melon (bitter gourd, karela)?

Bitter melon is a climbing plant in the gourd family that grows in tropical and subtropical regions of Asia, South America, East Africa and the Caribbean, according to Memorial Sloan Kettering Cancer Center (MSK). The fruit is eaten green, cooked as a vegetable in many cuisines. Its strong bitterness comes from compounds such as alkaloids, momordicosides and momordicines. Karela is its common name in India, and balsam pear is the name used in the USDA database, which also lists the leafy tips of the vine as a food.

Bitter melon nutrition (USDA)

The table uses USDA FoodData Central SR Legacy entries for raw bitter gourd pods (FDC 168393), boiled pods without salt (FDC 168394) and boiled leafy tips without salt (FDC 168392). Percent Daily Values (%DV) use the FDA Daily Values on Nutrition Facts labels.

Bitter melon is mostly water and very low in calories. Boiled pods have less vitamin C than raw pods in USDA data, but a cooked cup still supplies close to half the Daily Value. The leafy tips are rich in vitamin K. That matters for people who take warfarin: the NIH Office of Dietary Supplements advises keeping vitamin K intake consistent rather than making sudden large changes, so talk to your clinician before eating the greens often.

Bitter melon benefits: what the blood sugar research shows

Lab and animal studies suggest that bitter melon compounds affect how the body handles glucose, and a 2003 pharmacy review (Basch and colleagues) noted that some of its components resemble animal insulin in structure. Human trials are a different story. They are mostly small, last 4 to 16 weeks, and use very different preparations: fresh juice, dried fruit powder, capsules of various extracts. That makes them hard to combine, and the major reviews reach different conclusions.

Put plainly, bitter melon benefits for blood sugar are possible but unproven. The most positive analysis still rated its own evidence low to very low quality, and the Cochrane authors found no single bitter melon preparation that had been tested twice. For context, a fasting glucose drop of about 0.7 mmol/L is roughly 13 points on the milligrams-per-deciliter scale used in the US. None of these reviews supports using bitter melon in place of prescribed diabetes care. If you have diabetes or prediabetes, keep following your care plan and tell your clinician about any herbal product you take.

Weight and cholesterol

Bitter melon is often included in weight-loss blends, but the trial data do not back that up. A 2024 meta-analysis (Zou and colleagues, Prostaglandins and Other Lipid Mediators) of 10 trials with 448 adults found no significant change in body weight, body mass index, waist size or body fat percentage. The 2023 Laczkó-Zöld analysis likewise found no significant effect on LDL, HDL or total cholesterol. On the safety side, that analysis also found no notable change in liver enzymes or creatinine in the short trials it reviewed.

Bitter melon side effects and who should avoid it

Eaten as an occasional vegetable, bitter melon is a common food. MSK notes that the seeds, extracts and large quantities of juice are what cause adverse effects. Reported bitter melon side effects and cautions include:

• Pregnancy: MSK advises against it because animal studies suggest it may cause birth defects, and the 2003 Basch review noted reduced fertility in mice. Ask your obstetric clinician before using any bitter melon product if you are pregnant or trying to conceive.
• Diabetes medicines: bitter melon may add to the effect of insulin and other glucose-lowering drugs. The Basch review lists reports of very low blood sugar with coma and seizures in children. Do not give bitter melon products to children.
• Seeds and G6PD deficiency: the seeds contain vicine, which MSK says may cause favism, with headache, fever, abdominal pain and coma. Favism is a breakdown of red blood cells that people with G6PD deficiency can develop, so anyone with that condition should avoid the seeds.
• Other medicines: lab studies suggest bitter melon affects P-glycoprotein and the liver enzyme CYP2C9, which handle many drugs. The clinical significance is unknown, so ask a pharmacist if you take regular medicines.
• Case reports: MSK lists an irregular heart rhythm in a young man after a few days of bitter melon juice, a stomach ulcer that needed a blood transfusion after half a liter of homemade extract, and kidney inflammation in two people using bitter melon products.
• Digestive upset: stomach and intestinal complaints are the most common side effect listed by MSK.

Seek urgent care for symptoms of low blood sugar such as shakiness, sweating or confusion, and tell your clinician about any herbal product you take before surgery or a new prescription.

Bitter melon supplements: reading the label

Bitter melon capsules and powders are dietary supplements, so the FDA does not approve them for effectiveness, and extract strengths are not standardized. A label may say 10:1 extract, meaning ten parts of fruit were concentrated into one part of extract, but that tells you little about which compounds are present. Many products combine bitter melon with other botanicals, which makes it hard to know what any single ingredient contributes. Look for third-party testing seals, as our guide to third-party tested supplements explains.

Two products in our store list bitter melon on the Supplement Facts panel, both as part of a blend:

• ForestLeaf Berberine lists a bitter melon fruit extract inside a botanical complex with gymnema leaf and Ceylon cinnamon, alongside a berberine complex. The label gives totals for each complex, not the amount of bitter melon, and tells people who are pregnant, nursing or taking any prescription medication to consult a physician first.
• Natnect GLP-1 Supplement lists bitter melon extract among 16 ingredients that include berberine, hops, capsicum and green tea. Despite the name, it is a dietary supplement, not a GLP-1 medication; our guide to GLP-1 support supplements explains the difference.

Both blends also contain berberine, which has its own interaction list; see our berberine side effects guide. For the other plants in these formulas, read our guides to gymnema and cinnamon, and our sibling article on nopal, another food studied for post-meal blood sugar.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines for blood sugar, are pregnant or have a chronic condition. 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: Nopal Benefits: Prickly Pear Cactus Nutrition, Research and Safety, White Mulberry Leaf: Benefits, Blood Sugar Research and Safety, Berberine Benefits: What the Research Shows and What It Does Not.