Yes it is safe. It comes in 3mg as well. Maybe try that and see if it works before going to the 5mg. It also comes in 10mg from vitamin companies. I usually get my from Puritan's Pride because the run a special, buy 2 bottles get 3 free. It is under $20 to get the 2 bottles and you end up with 5 bottles. Shipping is only $4.95 regardless of how much you order.

http://www.puritan.com/