Melatonin is widely known as the “sleep hormone” because it helps regulate the body’s sleep-wake cycle.
Many people use melatonin supplements to improve sleep quality, manage jet lag, or address insomnia.
However, growing research suggests that melatonin may also influence blood sugar levels and insulin function, raising important questions for people with diabetes or glucose intolerance.
To understand the connection, it is important to first look at insulin. Insulin is a hormone produced by the pancreas that helps the body use or store glucose, which is the main source of energy in the bloodstream.
Insulin sensitivity refers to how effectively the body’s cells respond to insulin. When insulin sensitivity decreases, blood sugar levels can rise, increasing the risk of type 2 diabetes.
Research indicates that melatonin can affect both insulin release and insulin sensitivity.
In the short term, melatonin may temporarily increase blood sugar levels, especially in individuals who already have impaired glucose tolerance or type 2 diabetes.
Scientists believe this happens because melatonin can reduce insulin secretion at certain times of the day, making it harder for glucose to move from the bloodstream into the cells efficiently.
A study published in the journal Sleep found that melatonin supplementation slightly raised blood glucose levels after meals in some individuals.
These effects were more noticeable in people with existing metabolic issues. However, the same research also noted that the increase was generally mild and temporary in healthy adults.
This means occasional melatonin use is unlikely to cause significant problems for most people with normal blood sugar control.
Interestingly, the long-term effects of melatonin may be different from its short-term impact.
Some newer studies suggest that prolonged melatonin use could modestly improve insulin sensitivity over time.
Improved insulin sensitivity means the body becomes more effective at using insulin to manage blood sugar levels.
Research involving individuals with type 2 diabetes has shown that regular melatonin supplementation may contribute to better average glucose control in certain cases.
Additional studies have also reported small reductions in fasting blood glucose levels among some participants taking melatonin regularly.
Fasting blood sugar refers to glucose levels measured after not eating for at least eight hours.
Lower fasting glucose levels are generally considered a positive indicator of metabolic health.
Despite these findings, experts caution that melatonin does not work the same way for everyone.
Factors such as dosage, timing, age, genetics, sleep patterns, and existing health conditions can all influence how melatonin affects blood sugar.
For example, taking melatonin during the daytime or at irregular hours may interfere with the body’s natural circadian rhythm and potentially worsen glucose regulation.
People with diabetes or prediabetes should be particularly careful when using melatonin supplements.
Monitoring blood sugar levels and consulting a healthcare professional before starting regular supplementation is recommended.
Some individuals may experience slight increases in glucose levels, while others may benefit from improved sleep and better metabolic balance over time.
Overall, current evidence suggests that melatonin can temporarily raise blood sugar in some people, particularly those with insulin resistance or type 2 diabetes.
However, these effects are usually small in healthy adults, and long-term use may even support better insulin sensitivity and fasting glucose control in certain situations.
As research continues, scientists are working to better understand the complex relationship between melatonin, sleep, and metabolism.
For now, melatonin should be viewed as a supplement that may influence blood sugar rather than a direct cause of diabetes or severe glucose imbalance.
Proper timing, moderation, and medical guidance remain key for safe and effective use.
