SHEET /m/melatonin · PubChem CID 896 · CAS 73-31-4 · REV 2026.07
Melatonin from source
C13H16N2O2 · 232.28 g/mol
Melatonine · N-Acetyl-5-methoxytryptamine · Circadin · 5-Methoxy-N-acetyltryptamine
hormone primarily released by the pineal gland
Fig. 1 · 2D structure RDKit
CC(=O)NCCC1=CNC2=C1C=C(C=C2)OC
Where you'll find it
Not yet mapped to everyday foods or products.
Still in your system computed
Melatonin clears on a half-life of 0.75 h. Every 0.75 hours, half of what's left is gone. Put in what you had:
The dose makes the poison inferred
A reported rat oral LD50 for Melatonin is 3,200 mg/kg, the dose lethal to half the animals tested. Scaled by body mass alone:
“The dose makes the poison” is a cross-species estimate shown as neutral science, not a threshold anyone should act on. Real toxicity depends on the person, not body mass alone.
Signature properties
Toxicity & hazards
Toxicity · LD50
3,200 mg/kg · very low toxicity · LD50 rat oral from source
The dose lens above scales this to a body weight.
Keep roaming
Where Melatonin leads
Melatonin is the hormone the brain releases as darkness falls to cue sleep. As a supplement it clears fast, with a half-life under an hour, so it nudges you toward sleep rather than holding you under like a sedative.