If you found yourself here maybe you are going thru something similar to what i went thru. Im creating this thread to help others and let you know that brain fog is only a temporary problem. Ive taken propecia on and off several times in the past and never had any problems. This last time i took it i was on it for about 3 weeks or so when i had an over whelming feeling of brain fog, I felt like i couldn't function, couldn't focus, think, read or even do the dishes. I was horrified and it crept up on me almost over night. I felt like I was never going to be the same again. Needless to say i quit immediately and the symptoms remained. Every day was harder then the last i was beginning to feel like I lost myself. I was like this for several weeks. It may have even been a months time. I can assure you (from my personal experience) that this is temporary. There is nothing wrong with you and over time your body and mind will restore itself. You may feel like there is no chance of you recovering but just hang in there and just understand that I went thru it and today I am totally back to normal. You just have to give your body time to adjust and you will be okay. If you have any questions for me feel free to ask. Personally i see a lot of people post about their problems and when they solve them they dont share their experiences. Its good to post whats wrong but it is important to follow thru and post when the problem is fixed. good luck and i hope this post has helped in some way.