"i took this about 7 hours after unprotected sex and was really nervous about it not working because i read something online about this not being effective for people weighing 175lb+ do not worry about this. if you take this within 72 hours you will be fine. i had cramps and was nauseous for the day after i took it (my body is not used to these hormones) and other than that, i started my period about a week earlier than i was expecting."