Systematic reviewPending medical review

The question: Does bitter melon (karela, Momordica charantia) improve blood sugar control in type 2 diabetes?
Who was studied: People with type 2 diabetes in randomised trials, pooled in a 2022 review of 199 trials (21,191 participants) covering 98 Ayurvedic medicines. Bitter melon was one of them. The number of bitter melon trials within the review is not in the research we have.
What they took: Bitter melon preparations, compared with a control group.
What happened: HbA1c, the blood test that reflects average sugar over the past two to three months, was 0.3 percentage points lower with bitter melon than with control (95% CI 0.1 to 0.4 lower).[1]
How strong is this: A large review of randomised trials, but the reviewers found that many trials reported their methods poorly, which pulled down their quality scores. A fall of 0.3 points in HbA1c is small.

The limits

Many of the trials did not report their methods properly, so they scored poorly on quality.
Many trials did not report side effects at all.
The two reviews disagree. The older Cochrane review found no clear benefit; see the questions below.
Some bitter melon preparations lowered blood sugar in trials. With diabetes medicines such as insulin or sulfonylureas, the effects could add up. See Karela and diabetes medicines.

Who paid for it

Not given in the abstract we read. We have not confirmed who paid for the review.

Questions people ask

What did the older Cochrane review find?

The 2012 Cochrane review included four trials with 479 people, lasting up to three months. It did not combine their results, because the preparations and the quality of the data differed too much. Bitter melon did not improve blood sugar control significantly compared with placebo, the trials were mostly at high risk of bias, and no two tested the same preparation. No trial measured death, illness from diabetes or quality of life.[2]

Is karela as good as metformin?

Not in the trials we have. In a four-week trial in people newly diagnosed with type 2 diabetes, the highest bitter melon dose lowered fructosamine, a marker of average sugar, by 10.2 micromol/L, against 16.8 with metformin. Only that highest dose showed a statistically significant fall from its own starting level. These are falls within each group, not a significant difference between bitter melon and metformin.[3]

Can I drink karela juice with my diabetes tablets?

Some bitter melon preparations lowered blood sugar in trials, so an effect could add to your medicine's. Tell your prescribing doctor before you add karela juice or capsules, and ask whether you should check your sugar more often.[1]

Interaction

Karela (bitter gourd) and diabetes medicines

Added to metformin and dapagliflozin, a karela extract lowered HbA1c further in a 2026 study. With insulin or sulfonylureas, low sugar is the worry.

Condition

Type 2 diabetes (sugar): what Ayurveda offers

Some herbs, such as methi and karela, lowered HbA1c a little in trials. Taken with diabetes medicines, they can add to the risk of low sugar.

Sources

Awaiting review by The Good Vaidya Medical Board. Prepared from the sources below and checked against each one.

Published 4 November 2026 · Last updated 4 November 2026

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Does karela (bitter melon) help type 2 diabetes?