Density and Supply of Donor Hair

How many hairs (grafts) does a person have to transplant?

I assume that you are talking about the donor hair supply. The supply is calculated by using the most bald person you can find. Assuming normal density of his hair, a person with the Norwood Class 7 hair loss pattern (the worst case) will lose 70% of the total hair he was born with. This will leave him with a 3 inch by 14 inch wreath of hair around the back and sides of his head. Assuming 100,000 original hairs averaging 2 hairs per follicular unit, that would mean that such a person could theoretically move half of the permanent wreath of hair (15,000 hairs or 7,500 grafts). There are other factors involved such as the looseness of the scalp and healing factors. We have a number of patients with Class 6 and 7 hair loss patterns than have moved between 15,000-20,000 hairs. The ones with the very high numbers generally had higher densities of the hairs on the head. One patient comes to mind had a birth hair population of about 150,000 hairs. He had 50% more to work with and he took advantage of that supply with wonderful results.

Generally, that is a lot of hair to move and unless you are very, very bald and have a very ‘perfectionist’ view of your need for fullnesss, most people get away with moving less hair.