Is the loss of body hair a normal side effect of finasteride?

Body hair loss is not a normal side effect of Propecia but we have heard patients state similar experiences.  If you are concerned follow up with your doctor.

Body hair loss is not a common side effect from finasteride. Be sure to speak to your prescribing physician for a full and comprehensive evaluation. Certainly there are many reasons for body hair loss.In one very large study of hair loss with use of the drug finasteride, patients were questioned on non-scalp body hair growth.
Finasteride did not appear to affect non-scalp body hair. However, more studies are needed to fully evaluate this question. Anecdotal reports have raised the issue of changes in facial and body hair but these have not been substantiated in large studies.Interestingly, individuals with a genetic deficiency of 5 alpha reductase (the enzyme finasteride inhibits) have reduced facial or body hair.  In some individuals it is markedly reduced (even absent) whereas in others it is only mildly reduced.  REFERENCES1. Propecia Drug Prescribing Information, Merck. 2. Inadomi et al.  Efficacy of Finasteride for Treating Patients with Androgenetic Alopecia who are Pileous in other Areas: A Pilot Study in Japan. Indian J Dermatol. 2014.3. Clin Endodrinol (Oxf) 1991 Apr;34(4):293-8. A cluster of male pseudohermaphrodites with 5 alpha-reductase deficiency in Papua New Guinea.

I have seen this happen infrequently, but it does happen. The cause may be the dependence of body hair on DHT. I pubished an article on Baldingblog on this very subject. See web reference below

Each medication has side effects, we always advise our patients to look up the side effects before using any medical treatment option for hair loss.  In different individuals it works differently and may cause a certain reaction.  If you notice hair loss of your body hair, it could be a reaction from propecia.