There are so many variables it makes this a tough answer. What you want to know is the half life (breakdown of the drug in the body). There are alot of questions, weight, percent body fat, site of injection, personal metabolic rate, liver function. I think the safest thing to say is that most bhcg products given to trigger ovulation are gone in 10 days.
That 10 is important, too. From ovulation, fertiization, to traveling down the tube to the uterus takes about 5 to 6 days, it takes about 4 days of implantation for a pregnancy making bhcg to give levels high enough to be detected with the best lab test. ( 6 +4 = 10).
Hope this helps,
JM
Most of the answers have been 10 days.