Is it safe for a 6 yr old child to take melatonin?

Melatonin is a hormone found naturally in the body.
Melatonin supplements are used for numerous conditions but has shown the most promise in short-term regulation of sleep patterns, including jet lag.
The FDA does not strictly regulate supplements including Melatonin so there is no guarantee of strength, purity or safety of products, and effects may vary.
There is limited study of melatonin supplements in children and safety has not been established.
You should always check with your health professional before giving Melatonin to children.
Doses of up to up to nine or 10 milligrams per kilogram of body weight, as a single dose or over several months, have been studied.
Dose ranges between 2 to 5mg have been given to children 6 months to 14 years of age with sleep disorders.
https://www.drugs.com/npp/melatonin.html