Considering Propecia. Worried about side effects. Better to take 1mg every other day? Will it work same?

If you are considering taking a medication it is best to discuss this with your doctor.  The recommended dose for Propecia a 1 pill (finasteride 1mg) a day.  

Taking a smaller dose will lessen your risk of side effects but it will also lessen the effectiveness on keeping your hair. Only a small percentage of patients experience side effects (a couple %) so I think most would say it's worth the risk. If you do have side effects they are reversible in most cases- just stop taking it (or drop to a half dose if you and your doctor decide that's best).

Finasteride was approved by the FDA and is indicated for the treatment of male pattern hair loss (MPB).  Since 5 mg of Finasteride is frequently prescribed for the treatment of prostate disease as well, extensive clinical studies were performed in order to address the efficiency and the side effects of the drug. As with all drugs, potential side effects exist and this is true with Finasteride as well. However, the side effects associated with Finasteride only affect a small percentage (2-3 %) of its users, and these side effects are mostly temporary ones. Given the effectiveness of the drug on both original and transplanted hair, the minor risk of potential side effects should not serve as an obstacle for the usage of the drug. The recommended dose is 1 mg per day.

Your fear is realistic.You may have Post-finasteride syndrome, occurs in men who’ve taken finasteride to treat hair loss by a chance of %4-5. That may causes some symptoms include: loss of libido, erectile dysfunction, depression, suicidal ideation, anxiety, panic attacks, Peyronie’s disease, penile shrinkage, gynecomastia, muscle atrophy, cognitive impairment, insomnia, severely dry skin and tinnitus. The condition often has a life-altering impact on victims and their families, such as job loss and the breakup of marriages and romantic relationships..

A half dose of finasteride (Propecia) will have 80% of the effect of a full dose of 1mg. There is no reason to take a half dose unless you know you have sexual side effects