Max dose of melatonin for adults?

Good answer, Tyrese!
"Effective starting doses for jet lag range from 0.3 to 0.5 mg. One milligram tablets can be cut in half to achieve a 0.5 mg dose if smaller doses are not available for purchase. Lower doses may work for some people, while others may need a higher dose, up to 3 to 5 mg. However, higher doses may be associated with more side effects such as headache, next day grogginess, or vivid dreams.
Always start with the lowest dose. According to a Cochrane review, doses over 5 mg appear to be no more effective than lower doses. It is important to note that much higher doses are available for sale in the U.S., but these doses may result in excessively high levels of physiologic melatonin."

1-10mg is usually safe.