19 yr. old stops taking effexor (venlafaxine) and her sex hormones drop to almost 0. after months still 0 and no period. how long before things get back to normal?

Zero?: There is no such thing as zero sex hormones. Is your partner consulting an md or do? If it's some other sort of 'practitioner' they are giving poor information. Although Effexor (venlafaxine) can affect libido, it doesn't change estrogen, Progesterone or testosterone levels to my knowledge.

Need further w/u: I agree are you talking about actual blood hormone levels or the fact that she has not had a period. Is she on other meds, eg antipsychotic med can stop periods. If she has relapsed off meds, anxiety and depression can cause missed periods. If you are seeing naturopath they often do tests that have questionable validity. See a gynocologist.