Melatonin: A Sleep Aid With a Surprising Connection to Cholesterol?

Melatonin is widely used by people who struggle to fall asleep or adjust to changes in their sleep schedule. Its primary role is to help regulate the body's internal clock. But researchers have also been investigating whether melatonin influences other aspects of health, including blood pressure, inflammation, blood sugar, and cholesterol.

One recent analysis has produced an intriguing finding: melatonin supplementation was associated with modest improvements in several cholesterol measurements.

It's an unexpected connection—and one worth examining without getting ahead of the evidence.

What Did the Researchers Find?

A systematic review and dose-response meta-analysis published in 2026 examined 63 randomized controlled trials investigating melatonin's effects on cardiometabolic risk factors. The researchers searched for eligible trials published through October 2025.

The pooled results showed the following average differences between participants taking melatonin and those in comparison groups:

These results suggest that melatonin may influence more than sleep regulation. However, the figures represent averages across studies, not guaranteed changes for an individual.

The researchers also found substantial variation among trials. Differences in participants, doses, treatment duration, and study methods make the results more difficult to interpret.

The important point: The observed changes were statistically significant for LDL, total cholesterol, and HDL in the pooled analysis, but that does not automatically mean they are large enough to make a meaningful difference to someone's long-term health.

Why Might Melatonin Affect Cholesterol?

Melatonin is best known as a hormone produced primarily by the brain's pineal gland in response to darkness. It helps coordinate the body's circadian rhythm—the roughly 24-hour cycle that influences sleep and many other biological processes.

But the body's internal clock is connected to metabolism, too.

Cholesterol production, processing, and transport are influenced by biological rhythms. Researchers have therefore investigated whether melatonin might affect pathways involved in lipid metabolism. Its interactions with oxidative stress and inflammation are also areas of scientific interest.

These mechanisms offer plausible explanations for why melatonin might influence blood lipid measurements. However, a plausible biological mechanism is not proof that taking a melatonin supplement will produce a predictable or clinically important benefit.

The exact mechanisms behind the findings remain uncertain.

Does Lower LDL and Higher HDL Mean Better Heart Protection?

Potentially beneficial changes in cholesterol measurements are interesting, but they need to be interpreted carefully.

LDL cholesterol plays a causal role in the development of atherosclerotic cardiovascular disease. Lowering LDL through treatments with established evidence can reduce cardiovascular risk.

HDL cholesterol, meanwhile, is associated with cardiovascular risk, but simply raising HDL does not necessarily protect against heart attacks or strokes. The effect depends on more than the HDL number alone.

The melatonin findings do not establish that supplementation prevents heart attacks, strokes, or the progression of coronary artery disease.

That distinction matters. A change in a laboratory measurement is not the same thing as proof of a better health outcome.

Could This Be an Added Benefit for People Who Already Take Melatonin?

This is where the finding becomes particularly interesting.

Some people already use melatonin to help with sleep. If further research confirms that it also produces modest improvements in certain lipid measurements, that could represent an additional benefit for some users.

But it is too early to treat that possibility as established fact.

The research does not demonstrate that everyone taking melatonin will experience these changes, nor does it establish the best dose, formulation, or timing for influencing cholesterol. It also does not show that taking higher doses to pursue a cholesterol benefit would be worthwhile or safe.

And people who do not need melatonin for sleep should not assume that the potential lipid effects provide a good reason to start taking it.

What About Safety?

Melatonin is commonly available without a prescription in the United States, but that does not mean it is appropriate for everyone or free of side effects.

Possible effects include daytime drowsiness, dizziness, and headache. It can interact with certain medications, and the quality and actual content of supplements can vary.

Long-term safety is also an important consideration. The 2026 meta-analysis did not evaluate adverse events sufficiently to establish the safety of melatonin supplementation from its findings.

Older adults, people taking multiple medications, and anyone with ongoing health conditions should discuss regular use with a healthcare professional or pharmacist, particularly if they experience daytime sedation or take medicines that may interact with melatonin.

No one should change prescribed cholesterol medication or other cardiovascular treatment because of this research.

What We Still Need to Know

The findings are promising enough to justify further investigation, but several questions remain unanswered:

• Are the cholesterol changes consistent across different populations?
• Do the effects persist with longer-term use?
• Which doses and formulations, if any, produce reliable benefits?
• Are the changes large enough to improve meaningful health outcomes?
• What are the long-term risks and benefits of regular supplementation?

Future trials need to answer these questions and assess cardiovascular outcomes and adverse effects, not just changes in blood tests.