This question was posed by a hair loss sufferer seeking hair loss help on our hair restoration forum and answered by Dr. Michael Beehner of Saratoga Springs, NY who is one of our recommended hair restoration physicians. His professional answer is below.
How many follicular units per cm2 (FU/cm2) does it take in hair transplant surgery to look thick? I am wondering if 35-40 FU/cm2 would be thick enough to meet my needs.
First of all, it should be noted that a very good recent research study by Coalition member Dr. Sharon Keene from Tucson, AZ showed that in “normal” men without male pattern baldness, the average follicular unit hair density at the front hairline was 51 FU/cm2 with a range of 38-78. The average density in the temple apex region (behind the recession) was around 44 FU/cm2 with a range of 25-64.
The biggest factor in predicting whether or not the 35-40 FU/cm2 density you mentioned would look “dense” is the diameter of the hair shaft. In a man with coarse hair, that could indeed look dense. In a man with fine hair, it would probably be “see-through.” The other factor besides just stating an FU number per cm2 is the number of hairs that the follicular units average out to. Obviously, at the very edge of the front hairline you would want all 1-hair grafts, but I think it’s important to switch to 2-hair grafts fairly quickly as soon as you get 2-3 grafts deep into the hairline zone.
What a person should be looking for, at least as far as the hairline is concerned, is the artistry of the hair restoration surgeon, not how many FU’s he can cram in a single CM2. If you get maximal density right up to the edge of the hairline, it looks very fake and has a tendency to look straight and unnatural, almost as if you were wearing a hairpiece.
A whole host of other factors also play a role. How steep of an angle is the hair going to be placed at? With extremely acute angles it is more difficult to achieve real high numbers, but often the steep angle looks more natural. Is the scalp thick or thin? If it is a thin scalp, the hair surgeon will want to decrease density so as to get enough vascular support to the grafts that are planted. It doesn’t do any good for a surgeon to heroically place 60 grafts in a square cm if only 60% of the follicles survive.
So the gist of my answer is that it is a nuanced, complicated question, not a simple one.
Mike Beehner, M.D.