A new study announced on January 12 reports that men using the hair loss treatment Propecia may experience some seriously bad side effects: loss of libido, erectile dysfunction, and growth of man breasts.

In addition to Propecia (finasteride), the study cites drugs such as Avodart (dutasteride) as having similar side effects. The new study, currently published online in The Journal of Sexual Medicine, examined drugs belonging to a group called 5a-reductase inhibitors (5a-RIs), which have been approved to treat lower urinary tract symptoms due to enlarged prostate, and may also prevent hair loss. Propecia is one of the drugs approved to treat hair loss examined in the study.

Yet US researchers issue "extreme caution" for those taking these drugs for either hair loss or urinary tract infections, due to side effects such as sexual dysfunction, the development of breast tissue in men, and depression brought by on by these side effects, researchers claim.

"Honest and open discussion with patients to educate them on these serious issues must be pursued prior to commencing therapy," urged study researcher Abdulmaged M. Traish of Boston University Medical Center in a statement. "In some patients, these adverse effects are persistent and may be prolonged and patients do not recover well after discontinuation from drug use."

In better news, earlier this month researchers discovered what may be an underlying cause of male pattern baldness: an inability of stem cells in the scalp to develop into the type of cells that make hair follicles. The discovery, published on January 4 in the Journal of Clinical Investigation, could give hope to men and women with hair loss, said the researchers in a release.

Last year, researchers also discovered a new gene related to hair loss that might facilitate therapy for many concerned. As reported by the science journal Nature, they found out that the gene APCDD1 is often responsible for so-called male pattern baldness, a hereditary process beginning during childhood. Officially termed hair follicle miniaturization, this process causes thick, dark hair to be replaced by much finer hair.

Read about hair loss and prevention here:

Access the study: http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2010.02157.x/abstract

Watch a video on ways to prevent balding: http://www.youtube.com/watch?v=2GHvyt6EdDI