All hair restoration surgeries will microscopically thin the scalp hair. The hairline lowering operation is no exception; however, the thinning is distributed throughout the top and back of the scalp, so it is imperceptible. I will be conducting scientific studies to actually measure this. Our initial impressions have been that the whole scalp is stretched about 10- 20% and therefore, the density goes down between 10% and 20% on the top and back. Therefore, if you have 100 follicular units/cm2 (as many women do), the hair density would become about 85 follicular units/cm2 after a 3cm hairline advancement. This difference would be imperceptible to the naked eye. Other hair restoration procedures such as follicular unit grafting by FUT, strip harvesting or FUE thin the hair similarly, but the recipient area rarely cannot get that degree of density unless multiple procedures are used.