Taking melatonin supplements seems to lower fasting blood sugar levels in adults by about 11.6 mg/dL on average. This effect is strongest in people whose blood sugar is already normal or only slightly high, but researchers caution that the current evidence isn't strong enough to rely on melatonin as a main treatment for blood sugar control.

Our current analysis shows that the evidence we've reviewed leans toward melatonin supplementation lowering fasting blood glucose levels in adults. Fasting blood glucose is the amount of sugar in your blood after you have not eaten for several hours. We found that taking melatonin appears to reduce fasting blood sugar by about 11.6 mg/dL on average. We analyzed the available research and found 45.0 studies support this effect, while 0 studies refute it. Our analysis of the available research suggests that this reduction is most noticeable in adults whose blood sugar levels are already normal or only slightly elevated [1]. We also note that the evidence we've reviewed suggests melatonin should not be relied upon as a primary treatment for blood sugar control [1]. What we've found so far points to a potential link, but we emphasize that this is a partial view based on the data we have reviewed. The evidence we've reviewed indicates a trend, but we do not have enough evidence to say this is a definitive solution. Our current analysis shows a consistent pattern across the assertions we examined, but the picture remains incomplete. If you are considering melatonin for blood sugar management, talk to your doctor first. The numbers we see are promising, but the evidence is not yet strong enough to replace standard care.