Metabolite Encyclopedia › Melatonin pathway
This is melatonin after your liver is finished with it. Almost all the melatonin you make ends up here, then leaves in your urine, which is how a researcher can read your night from a lab sample instead of waking you up for blood draws.
- Also called6-OHM
- Made inYour liver
- Built fromMelatonin, by CYP1A2
- Measured as6-sulfatoxymelatonin
Three things worth knowing
It is why sleep research can use a urine sample. Melatonin itself disappears from blood within a few hours, so catching its peak means sampling repeatedly through the night. The sulfated form of 6-hydroxymelatonin collects in urine instead. One overnight collection gives a usable picture of how much melatonin a person produced and roughly when.
Caffeine and melatonin share a bottleneck. The liver enzyme that performs this conversion, CYP1A2, is the same enzyme that clears caffeine out of your system. Two very different molecules, one shared piece of machinery.
How fast people run this step varies a lot. CYP1A2 activity differs widely from person to person, and smoking is one of the things known to speed it up. Two people can produce the same amount of melatonin and clear it at noticeably different rates.
The signal and the receipt
What a study has to control for
- Light at night
- Caffeine
- Shift work
- Age
- Smoking
Every one of these changes either how much melatonin is made or how fast it is converted. They are the reason a single number from a single night does not mean much on its own.
Questions people actually ask
Is 6-hydroxymelatonin the same as melatonin?
No. It is what melatonin becomes after the liver modifies it. Melatonin is the active signal. This is the breakdown product on its way out.
Can you take it as a supplement?
It is not sold as one, and there would be little point. The body makes it in order to get rid of melatonin, not in order to use it.
Why do labs measure the sulfate version?
Because 6-hydroxymelatonin gets a sulfate group attached before excretion. That form, 6-sulfatoxymelatonin, is what actually shows up in urine in measurable amounts.
How does this relate to sleep?
Indirectly, as a marker. Researchers use it to estimate melatonin output in people they cannot keep in a lab overnight. The sleep work is about melatonin itself, not about this metabolite.
6-hydroxymelatonin is one of more than 2,000 metabolites AHARA mapped across its Reishi and Lion's Mane elixirs. You can browse the rest of what is in the bottle.
Open the Metabolite EncyclopediaReferences
Ma X, Idle JR, Krausz KW, Gonzalez FJ. Metabolism of melatonin by human cytochromes P450. Drug Metab Dispos. 2005;33(4):489-494. doi:10.1124/dmd.104.002410
Benloucif S, Burgess HJ, Klerman EB, et al. Measuring melatonin in humans. J Clin Sleep Med. 2008;4(1):66-69. doi:10.5664/jcsm.27083
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