In some people, LDN can cause increased sleepiness. Rarely someone will complain about it making them fatigued the next day. For these people, I recommend taking it earlier in the evening (around dinner time) to see if that helps and sticking with it for a few weeks as usually, this side effect will go away. For those who continue to feel fatigued throughout the day, I recommend lowering the dose. Even using 1 mg of LDN can provide benefit.
Just as some people will experience vivid dreams when they first start LDN - this will go away on its own after a week or two.
Other people will experience a stimulatory effect. These people should take LDN in the morning rather than at night.