It’s hard to tell the actual percentage of those experiencing long-term side effects, but I personally feel there’s reason to believe it’s above 2% of users as Merck suggests. Regardless, while some Propecia users aren’t greatly affected by a 75% decrease in DHT nor experience abnormal mental fog or anxiety, a substantial amount have reported their lives falling apart due to the side effects which failed to disperse post-usage as Merck claimed.
While its normal to have a decline in sexual interest while using Propecia, if you’re having ED, shaft numbness, anxiety or depression, you should know it’s the finasteride. Apparently a number of individuals cease the drug and recover, so at that point, you would hope this includes yourself. Chances are it will.
If you’re relatively okay now, you’re alright - just take it with close supervision of your Doctor. If you intend to stop, weening off the medication can possibly be better than abruptly stopping with concern of shocking your system. Inform your Doctor that certain men react negatively to Propecia’s effects and that it can induce mental as well as sexual side effects, and from there discuss your future with the med.
Hope that helps.