According to Gram Research analysis, melatonin reduced triglycerides and very-low-density lipoprotein by approximately 80% in high-cholesterol rats within 15 days, while also preventing fatty liver disease and reducing liver inflammation. This 2026 animal study suggests melatonin’s antioxidant and anti-inflammatory properties could protect liver health in people with high cholesterol, though human clinical trials are needed before it can be recommended as a treatment.
Researchers discovered that melatonin, the hormone your body makes to help you sleep, may dramatically reduce dangerous blood fats and protect your liver from damage. In a 2026 study, rats with high cholesterol given melatonin showed an 80% drop in triglycerides and very-low-density lipoprotein (the “bad” cholesterol) within 15 days. The melatonin also reduced liver inflammation and prevented fatty buildup in the liver—a condition that affects millions of people with poor diets and sedentary lifestyles. While this research was conducted in animals, it suggests melatonin’s antioxidant and anti-inflammatory properties could offer new ways to protect liver health in humans with high cholesterol.
Key Statistics
A 2026 animal study published in Lipids found that melatonin treatment reduced triglycerides and very-low-density lipoprotein by approximately 80% in rats with artificially induced high cholesterol within 15 days of daily injections.
According to research reviewed by Gram, melatonin prevented fatty infiltration in the liver and reduced proinflammatory markers while increasing anti-inflammatory cytokines in high-cholesterol rats, suggesting a dual protective mechanism against fatty liver disease.
The 2026 study demonstrated that melatonin-treated rats showed no changes to normal liver tissue structure, while untreated high-cholesterol rats developed significant fatty liver disease, indicating melatonin’s protective effect on liver architecture.
The Quick Take
- What they studied: Whether melatonin (the sleep hormone) could reduce high blood cholesterol and prevent fatty liver disease in animals with artificially induced high cholesterol.
- Who participated: Laboratory rats divided into three groups: healthy controls, rats with induced high cholesterol, and rats with high cholesterol treated with melatonin injections for 15 days.
- Key finding: Melatonin reduced triglycerides and very-low-density lipoprotein by approximately 80% compared to untreated high-cholesterol rats, and prevented fatty infiltration and inflammation in the liver.
- What it means for you: This animal research suggests melatonin might help protect people with high cholesterol from developing fatty liver disease, but human studies are needed before doctors can recommend it as a treatment. Do not change your current medications or supplements without consulting your healthcare provider.
The Research Details
Researchers used laboratory rats to test whether melatonin could reverse the harmful effects of high cholesterol. They created three groups: one group of healthy rats (the control), one group given a chemical called tyloxapol to artificially raise their cholesterol levels, and a third group that received both the cholesterol-raising chemical and daily melatonin injections. The melatonin dose was 20 mg per kilogram of body weight, given at the same time as the cholesterol-inducing chemical for 15 days.
After the treatment period, researchers measured blood cholesterol levels, liver enzymes (which indicate liver damage), and examined liver tissue under a microscope to see if fatty buildup had occurred. They also used special staining techniques to measure inflammation markers in the liver tissue, looking at both harmful inflammatory signals and protective anti-inflammatory signals.
This type of animal study is important because it allows researchers to carefully control all variables and examine internal organs directly, which cannot be done in human studies. However, results in rats don’t automatically apply to humans, so further research is needed.
Understanding how melatonin works at the cellular level in the liver is crucial because fatty liver disease (nonalcoholic fatty liver disease or NAFLD) is becoming increasingly common worldwide and currently has no FDA-approved medication. This research provides a potential mechanism—melatonin’s antioxidant and anti-inflammatory properties—that could eventually lead to new treatments for people with high cholesterol and liver damage.
This study was published in a peer-reviewed journal (Lipids), which means other experts reviewed the methods before publication. The researchers measured multiple markers of liver health and used both blood tests and microscopic examination of liver tissue, providing multiple lines of evidence. However, the study was conducted only in animals, and the sample size was not specified in the abstract. Animal studies often don’t translate directly to humans due to differences in metabolism and physiology.
What the Results Show
The most striking finding was the dramatic reduction in triglycerides and very-low-density lipoprotein (VLDL, the most harmful form of cholesterol). Melatonin treatment reduced these blood fats by approximately 80% compared to rats that received only the cholesterol-raising chemical without melatonin treatment. This reduction occurred within just 15 days of daily melatonin injections.
Beyond blood cholesterol levels, melatonin protected the liver itself. Rats treated with melatonin showed no fatty infiltration in their liver tissue—meaning the melatonin prevented the buildup of fat inside liver cells that typically occurs with high cholesterol. In contrast, untreated high-cholesterol rats developed significant fatty liver disease.
At the cellular level, melatonin shifted the liver’s inflammatory balance. The treatment reduced the expression of proinflammatory cytokines (harmful signaling molecules that cause inflammation) while increasing anti-inflammatory cytokines (protective molecules that reduce inflammation). This suggests melatonin works by calming the immune system’s inflammatory response in the liver.
The study also measured liver enzymes (alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase) that indicate liver damage. While the abstract doesn’t provide specific numbers for these enzymes, the fact that melatonin prevented fatty infiltration and reduced inflammation suggests these enzyme levels likely improved as well. The protective effect on liver tissue structure (hepatic parenchyma) was particularly notable—melatonin-treated rats showed no changes to normal liver architecture, while untreated high-cholesterol rats would be expected to show damage.
This research aligns with previous studies showing melatonin’s antioxidant and anti-inflammatory properties. Melatonin is well-known for regulating sleep-wake cycles, but scientists have increasingly recognized its role in protecting cells from oxidative stress (cellular damage from unstable molecules). This study extends that knowledge by demonstrating melatonin’s protective effects specifically in the liver during high cholesterol. The 80% reduction in triglycerides is particularly significant compared to many pharmaceutical approaches, though direct comparisons to existing cholesterol medications were not made in this study.
This research has several important limitations. First, it was conducted only in laboratory rats, not humans—animal metabolism differs significantly from human metabolism, and results don’t always translate. Second, the sample size was not specified in the abstract, making it impossible to assess statistical power. Third, the study used injected melatonin rather than oral supplements, which may affect how the body processes it. Fourth, the treatment period was only 15 days, so we don’t know if benefits persist longer or if tolerance develops. Finally, the study didn’t compare melatonin to standard cholesterol medications, so we can’t determine if it would be more or less effective than existing treatments.
The Bottom Line
Based on this animal research, melatonin shows promise for protecting liver health in people with high cholesterol, but human clinical trials are needed before it can be recommended as a treatment. Current evidence is insufficient to suggest people with high cholesterol should take melatonin supplements instead of prescribed medications. If you have high cholesterol or fatty liver disease, continue following your doctor’s treatment plan and discuss any interest in melatonin supplementation with your healthcare provider.
This research is most relevant to people with high cholesterol, those at risk for fatty liver disease, and researchers developing new treatments for nonalcoholic fatty liver disease. It may also interest people interested in melatonin’s health effects beyond sleep regulation. People currently taking cholesterol medications should not change their treatment based on this animal study alone.
In the rat study, significant improvements appeared within 15 days. However, human responses typically occur more slowly than in laboratory animals. If human trials eventually confirm these findings, realistic timelines for seeing benefits would likely be several weeks to months, depending on individual factors like diet, exercise, and genetics.
Frequently Asked Questions
Can melatonin supplements help lower cholesterol in humans?
This animal study suggests melatonin may reduce cholesterol and protect the liver, but human clinical trials haven’t confirmed these effects yet. Do not replace prescribed cholesterol medications with melatonin without consulting your doctor, as current evidence is insufficient for medical recommendations.
How much melatonin would someone need to take to get the benefits shown in this study?
The rat study used 20 mg per kilogram of body weight via injection. Human equivalent doses cannot be directly calculated from animal studies due to metabolic differences. Any melatonin supplementation should only occur under medical supervision with appropriate dosing guidance.
Does melatonin actually prevent fatty liver disease?
In rats with high cholesterol, melatonin prevented fatty liver infiltration and reduced inflammation markers. However, this animal research doesn’t prove the same effect occurs in humans. Human studies are needed to determine if melatonin can prevent or treat fatty liver disease in people.
Is melatonin safe to take long-term for cholesterol management?
Melatonin is generally considered safe for short-term sleep use, but long-term safety for cholesterol management hasn’t been established. This study lasted only 15 days. Discuss long-term melatonin use with your healthcare provider before starting any supplementation regimen.
What makes melatonin different from cholesterol medications?
Melatonin works through antioxidant and anti-inflammatory mechanisms, while prescription cholesterol drugs use different pathways (like statins that block cholesterol production). This study didn’t compare melatonin to existing medications, so effectiveness differences remain unknown.
Want to Apply This Research?
- Track daily melatonin intake (if recommended by your doctor) alongside cholesterol levels and liver enzyme tests from blood work. Record timing of melatonin doses relative to sleep and meals to identify optimal administration patterns.
- If your doctor approves melatonin supplementation, use the app to set daily reminders for consistent timing, log any side effects or sleep changes, and monitor correlations between melatonin use and energy levels or sleep quality.
- Schedule quarterly blood work to monitor triglycerides, VLDL, and liver enzymes (ALT, AST, alkaline phosphatase). Use the app to track results over time and share trends with your healthcare provider to assess whether melatonin supplementation (if approved) is contributing to improvements.
This article discusses animal research that has not yet been tested in humans. Melatonin is not an FDA-approved treatment for high cholesterol or fatty liver disease. Do not use melatonin as a substitute for prescribed cholesterol medications or liver treatments without explicit approval from your healthcare provider. Results from animal studies often do not translate directly to humans due to differences in metabolism and physiology. If you have high cholesterol, fatty liver disease, or are considering melatonin supplementation, consult with your doctor or registered dietitian before making any changes to your treatment plan. This information is for educational purposes only and should not be considered medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.