Melatonin levels in the blood are highest in young people (55–75 pg/ml) and start to decline after the age of forty, with the fastest decrease found from sixty years of age onward, reaching very low levels in the elderly (18–40 pg/ml). New research suggests that melatonin may have protective effects against many cancers, which may be part of the reason that as people age—and melatonin levels go down—they are more susceptible to cancers.
