Switching from oral to topical Minoxidil?

Thanks for the question. You are likely to experience shedding but for a different reason than you ask about and perhaps a different reason than you think. You are not likely to get shedding simply because you are starting topical minoxidil. No. However, you are likely to experience shedding because you are not able to supply your scalp with the equivalent amount of minoxidil by using the topical compared to the oral minoxidil. 5 % foam is not equivalent to 2.5 mg so you hair will likely say “where is my minoxidil?” If you have been using it a very short time, it may not be a big issue. But if you have been using oral minoxidil at 2.5 mg for some time it could be an issue. Be sure to discuss fully with your dermatologist. The key point here is that 2.5 mg of oral minoxidil is not equivalent to topical minoxidil so you are now likely underdosing.