Is there a best timing in the menstrual cycle to do a PRP for hair loss? Do hormones levels have any influence?

While hair growth is certainly under hormonal influences this should not impact the timing of PRP treatment during the menstrual cycle. This is because the normal changes in hormone levels during the cycle are negligible with respect to impact on the hair growth cycle. However, if you are taking exogenous hormones, such as an oral contraceptive, these may potentially impact hair growth. Be sure to find an experienced physician with PRP expertise.