The Study
Pharmacokinetics of melatonin in man: first pass hepatic metabolism.
This study looks at how the body processes melatonin by comparing healthy people to those with liver disease. It can only show that liver problems are connected to different melatonin levels, not that the liver disease directly causes the change. We can't be sure if other factors, like age or other medicines, are actually responsible for the difference.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
This research looked at how the body handles melatonin when taken as a pill versus an injection, and how much melatonin the body naturally makes. It found that the liver quickly breaks down most oral melatonin before it reaches the rest of the body. It also compared how much melatonin healthy people make versus people with severe liver disease.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 527 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this is significant because it explains why oral melatonin supplements often require higher doses to work, and why people with liver disease naturally produce less melatonin, which may affect their sleep cycles.
- 2Healthy adults produce about 28.8 micrograms of melatonin daily, while those with cirrhosis produce only 12.3 micrograms.
- 3Oral melatonin has low bioavailability because the liver metabolizes it heavily before it enters the bloodstream.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of clinical endocrinology and metabolism
Year
1985
Authors
E. Lane, H. Moss
Related Content
Claims (5)
People with severe liver disease (cirrhosis) have trouble making and clearing melatonin, which changes how much of this sleep hormone is in their bodies. This happens because the damaged liver can't process or produce the hormone properly.
When you take a melatonin pill, your body only absorbs about 15% of it because most of it gets broken down by your liver before it enters your bloodstream. Even so, the amount that does get absorbed can still be up to ten times more than what your body naturally makes at night.
Your body naturally makes about 28.8 micrograms of melatonin every day when you're healthy. This normal amount helps your brain keep your sleep-wake cycle and daily rhythm on track.
People with severe liver disease make about half as much of the sleep hormone melatonin as healthy people do. This happens because a damaged liver struggles to help the body make or control this important chemical.
When you swallow melatonin, your liver breaks down a large portion of it before it can enter your bloodstream. Because of this, you need to take a much larger pill to get the same amount of the hormone in your system as you would from an injection.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.