This is one of the most common questions in all of hair loss medicine so it's important that you understand all the intricate details.First, you are not allergic. In general, individuals who are allergic develop itching, burning, pain, blisters, redness in their scalp. Often, they want to scratch and scratch their scalps or they have rashes on their ears and necks (because they medicine rinses off when in the shower). There are several reasons why an individual using a product can have more hair lossREASON 1. THE PRODUCT DID NOT HELP THEMThere is no product available anywhere that is 100 % effective. At best, the odds are 40-60% with the very very very very best of treatments available that regrowth will be seen. Minoxidil, Propecia, PRP, LLLT - all these treatment "can" help but they don't always. There are a lot of great stories of regrowth (and amazing before and after photos) - but there are alot of patients that do not get growth and feel frustrated.Check with the company of the product you are using - they can tell you the clinical studies on the precise chances of regrowth. Clinical studies with the product you are talking about showed many men felt their hair was better - but certainly not all!It's possible that your genetic hair loss just progressed along and you experienced more hair loss from this condition (called androgenetic alopecia).REASON 2. THE PRODUCT HELPED THEM A BIT BUT THEIR GENETIC HAIR LOSS WON OUT AND THE RESULT WAS SLIGHTLY MORE HAIR LOSSWhat you don't know is would you have less hair if you didn't lose the product. I like to think of genetic hair loss as a car traveling down the road. If it travels at 10 miles per hour and somehow I change the car so that it can only go at 2 miles per hour - we still progress down the road- albeit a bit slower. It is possible your genetic hair loss would have progressed much much faster, but that the treatment in question has slowed it down.REASON 3. THE PRODUCT HELPED ALOT BUT YOU HAVE A SECOND REASON FOR HAIR LOSS NOW It's important to keep in mind that there are dozens and dozens of reasons for hair loss. It's possible the product helped you but now you have a second condition. You might consider seeing a physician who is knowledgable about all causes of hair loss so that he or she can view your scalp "up close" and also discuss whether blood work is needed to check your iron or thyroid or other tests. If your genetic hair loss was under good control with the product you are mentioning, and now you start developing a thyroid problem - guess what will happen? You'll notice more hair loss.REASON 4. THE PRODUCT HELPED ALOT BUT THE NEW MEDICATION IS CAUSING HAIR LOSSIn general, some users of finasteride notice that they get a bit more hair shedding in the first months of use. This is common. This would lead to worsening hair loss before it recovers.All in all, if you are worried about your worsening hair loss, be sure to check in with a knowledgable physician for guidance. Genetic hair loss can be stopped (and improved) in some men, but certainly not all. For each medication or treatment that you start using, ask about the chances of success. Is it 30 %? 50 % 90 %. It is never 100% and a lot of treatments hover around 40-60 %.