The Claim
Oral administration of melatonin at doses of 2 mg and 4 mg yields an absolute systemic bioavailability of approximately 15% in healthy adults, indicating significant first-pass elimination and substantially lower active drug concentrations compared to intravenous administration.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
When you take melatonin pills, your body only absorbs about 15% of the dose into your bloodstream because most of it gets broken down before it can circulate. This means oral supplements deliver much less active melatonin to your system compared to an injection.
See the scientific wording
Oral administration of melatonin at doses of 2 mg and 4 mg results in an absolute systemic bioavailability of approximately 15% in healthy adult populations, indicating that the majority of the ingested compound is eliminated before reaching systemic circulation. This finding highlights the substantial reduction in active drug concentration following standard oral supplementation compared to direct intravenous administration.
What the research says
1 studyStudy: The Absolute Bioavailability of Oral Melatonin
The study confirms that when healthy adults take 2 or 4 mg of melatonin by mouth, only about 15% actually reaches their bloodstream, meaning most of it is broken down before it can work.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.