Sampling Time
Approximate Normal Range (Saliva
Melatonin)
Daytime (10 a.m. -4 p.m.): < 5
(often below detection limit)
Evening (9- 11 p.m.): 3-15
Midnight (2 - 3 a.m.):
(may reach up to 100)
30-80
Early Morning (6- 8 a.m.): < 10,
declining rapidly
Peak levels occur between 2:00
and 4:00 a.m.
Lowest levels are during daylight
hours, especially around noon.