The short answer to your question is that there are no safe over the counter medications that can be used for trouble sleeping. Most medications that are over the counter that people take for sleep have diphenhydramine in them (brand name is Benadryl). Diphenhydramine does indeed induce drowsiness, but it also disrupts the normal progression of the sleep cycle over the night, so although it may help you fall asleep that does not mean that you will get good sleep. It is probably ok to take it once in a while, but it should not be relied upon as a sleep aid.
It is better to focus on things that make falling asleep harder or impair sleep, and eliminate those. In general, the biggest culprit is caffeine, and you could try eliminating all caffeine in the afternoons and evenings and seeing if that makes a difference. Alcohol also has very bad effects on sleep, inducing drowsiness but then leading to early morning awakenings and disruption of the sleep cycle.
If the problem persists, the best solution would be to see your primary care doctor
. They can first determine if there is a treatable medical problem causing the insomnia
and also prescribe you a medication to help with sleep.