Keith Kaufman of Merck, senior director of clinical research in endocrinology and metabolism, presented 2 year study data on Propecia at the 1998 American Academy of Dermatology Conference.  Dr. Kaufman showed slides detailing two year frontal (mid-anterior scalp, an area about 1 inch behind a normal hairline) results, including photographs of patients.  Hair counts were shown to improve from around 10-11 additional haris per centimeter after one year to around 11-12 hairs per centimeter after two years, so results were maintained with slight improvement.   Patients on placebo showed a sharp decrease in hairs in the first year.  I am awaiting confirmation of exact numbers (a line graph was presented), but the decrease after one year was about 5 hairs per centimeter.  After the first year, patients were placed on Propecia and showed an overall 8 hair increase per centimeter by the end of the second year, for a total of 3 hairs above baseline.  The following table shows improvements judged by photographic analysis:

No patients in either group re rated as greatly improved.

See example photos of Propecia study patients