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One aspect puzzles me. In FUT a strip is removed and closed so a part of the scalp vanishes and is replaced by a thin scar. The areas adjoining the scar retain their hair density and very often with trichophytic closure hair grows out of the scar, again with no reduction in density.

In FUE follicular units are harvested individually. No large scar is generated but hundreds (thousands?) of tiny ones. However (and this is my main point), donor area density is reduced because the scalp from where the hair is removed does not vanish and is essentially now a tiny bald spot.

Does this mean FUE thins out the donor area in return for not creating a long FUT scar? Is that the trade-off?

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Thanks for asking, as this can be a bit abstract.

When you remove a strip of hair (say 1/2 inch wide by 4 inches long) you are effectively removing skin and pulling the scalp from top and bottom. This in effect stretches the scalp/skin along with the hairs. So if you have a very, very precise measuring tool of hair density before and after the surgery, then you will definitely see a decrease in hair density after the surgery… but this reduction in density is very low and not perceptible to the naked eye.

When follicular unit extraction (FUE) is performed, many hundreds and thousands of hairs are taken out (and never grow back on that spot) so it is easy to see how this would also reduce the donor density.

Tags: density, fue, strip surgery, hair transplant, hairloss, hair loss


Solid good data base you have built on this blog Dr. rassman. Thank you

My question is: Can you transplant hair from the upper sides of the head “left and right” about 3 inches above the ears, or is it only possible as a donor area to be from the lower back above the nick ? Reason I’m asking this question is because I have what i want to define as “Global hair loss/damage”. Meaning even in the donor area it’s clearly visible that i do not have a normal hair distribution/density “there is holes among the donor area” but, in my sides “just below the flat crown of my head” the hair is extremely healthy/dense/thick and can grow for long time with out being damaged.

Your time and answers are greatly appreciated

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NW7First I though you were describing diffuse unpatterned alopecia (DUPA), but if there are clearly areas of your scalp that are full and lush, and they are about 3 inches above the ear, I would rule out DUPA on first glance. I would have to examine you to understand what you are telling me.

As a rule, however, the donor fringe is only 2 1/2 inches high on the back of your head and about 3 inches high on the side above the ear. Donor hair implies that the hair is permanent when full balding (up to a Class 7) occurs. Note the diagram at right of a Class 7 figure and you will see the 3 inches high fringe above the ear. Donor hair taken above the 3 inch level will not be permanent hair for the advanced balding patient.

Tags: donor area, donor, hair transplant, hairloss, hair loss, density


First off, great site doc. Very helpful.

My question is about hair density and thickness. Say one buzzes their hair, should they expect the density and thickness of the hair to be the same over the whole head or are the backs and sides of the head thicker than the top of the scalp, generally?

Thanks, doc!

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If you’re not balding, the density should be the same all over the head. If you are balding, density will vary with the pattern of genetic balding. Of course, there will be normal variations as well.

Tags: density, hairloss, hair loss


How many more grafts can you gain if you add FUE. Say i had three strips for 6000 grafts and i’m stripped out. how many on average more grafts can a person get with FUE? One doctor said between 1000 and 2000. Does this sound accurate? thank you

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Your laxity might be good after three strip surgeries, but some patients might find the donor area to be tight. The higher the density at the time of the follicular unit extraction (FUE) harvest, the greater the yield will be. For an FUE, the remaining density will reflect your depletion of 6000 grafts from the original permanent zone. For those men with a high original density, there could be many more grafts available… and for those with an average or below average density, the different yield could be significant. If I examined you, I might be able to give you an educated guess, but there is no general answer to your question. A graft estimate of between 1000-2000 grafts is possible, but an examination is critical to the estimating process.

Tags: laxity, fue, hair loss, hairloss, hair transplant


Hello, I just had a wonderful procedure. Their offices were clean, procedures were excellent, and the staff was very accommodating. In 2002 I had 800 grafts done by another group in San Francisco and then again I just did 3500 grafts. The follicles were transplanted throughout my scalp approximately 25 FU/CM2. I have a very nice NW2 hairline. Also, I had a very high number of 4-hair grafts. Over 400 of them! They excised a strip of 3500 grafts and got 3703!!!

Do most of your patients get about 25FU/cm2 and are happy with it? I think it will be ok but just need reassurance.

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A normal person will have 1250 hairs or 600 two-hair follicular units. When converted to cm/square, that would extrapolate to 100 follicular units per square cm. If you received 25 follicular units in 1 cm, that would suggest that in one procedure, the doctor returned 25% of your normal density on the transplanted area. This is often not really the case, as some areas will have higher densities put in and other areas lower densities. For a person with average weight hair, olive skin, and brown hair, 50% densities overall should be more than enough to produce a full appearance. If you had a high number of four-hair grafts, then that might mean that your overall densities are higher than average. I generally target 25% density return on the first session, but at times I will go higher or lower depending upon other factors.

Tags: hair transplant, density, surgery, follicular unit, hair restoration


I’ve read that the average density of hair in the donor area is 2.0 hairs per square millimeter. I have a density of 2.2, which obviously is above average but how much? Is it slightly, moderate, or very high? Also, what’s the highest density you’ve ever seen on a patient?

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The difference between a 2 or 2.2 density could be the normal variation around your scalp. High densities have ranged from 2.6-4.0. Let’s take a look at a patient with a density of 4.0, who has now had nearly 9200 grafts transplanted. Before on the left, after on the right (obviously). Click the photos to enlarge.


To see more photos of this this patient’s remarkable transformation, click on Patient ZU.

Tags: density, hair transplant, hairloss, hair loss


Hello Dr. Rassman, could you tell me what the difference between “thinning hair”, “Hair Loss”, “Miniaturization”, “Low and High Density”?

Also when people say poor nutrition, e.g. anorexia, zinc deficiency etc, causes thinned hair do they mean the shaft diameter of each hair decreases or hair falls out resulting in low density?

Thank You

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Dictionary“Thinning hair” means a person is losing hair (usually hair that is miniaturized – i.e. thinning of the hair shaft) and does not have as much hair bulk as they once had. “Miniaturization” of hair means that a person’s hair shaft is not as thick in one area when compared to another area as it should be in its normal/healthy state. It is normal to have around 10% of miniaturized hairs for people who are not balding that may reflect what we call vellus hairs, present in every follicular unit.

“Density of hair” describes how many hairs are in a given area of scalp. For example an average Caucasian male can have a hair density of 2 hairs per square millimeter of scalp (which translated to about 100,000 hairs on a typical head size). If it is found that the density is 3 hairs per square millimeter, than the person is said to have a high hair density (born with about 150,000 hairs on the head). Hair density is variable and may depend on the ethnicity or race of a person as much as the inheritance patterns. Caucasians are born with an average of 100,000 hair on their heads, Asians about 80,000, and Africans about 60,000. These numbers are just averages and do not necessarily apply to what you may have on your head.

Tags: hair loss, hairloss, thinning, miniaturization, density


I recently underwent a 1700 FUT procedure in the temples with a very respected surgeon. I followed all post-op instructions. A day after the surgery I noticed that the incisions on the left side temple looked closer than the right and I could see more hair coming from them. It is now 13 days post op and all scabs are gone. It seems that the hairs are more dense on the left side of my head than right.

My question is if the density of the hair I see that was transplanted is indicative of the final density I will see? If the right side looked less dense a day after surgery and looks less dense 13 days after surgery does that mean it will likely be less dense in the final result or can small hairs be transplanted below the skin hence not being seen until they grow out?

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What you see is what you will probably get. Ask you doctor about it — maybe he did it intentionally as part of a plan he had for you.

Tags: density, hair transplant, hairloss, hair loss



I had an hair transplant on my temples about 7 months ago. After my transplant I had minimal and certainly not complete at all loss of transplanted small hair. After about 5 months I could see results which were incredibly positive and the hair in the transplanted areas was long and rather thick.

What I have experienced in the last 2 months has been a visible decrease in density of the transplanted hair. Is this possible? Also my hair loss in non transplanted areas has increased (I have been on propecia for 8 years)

Thanks a lot for your help

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It is difficult for me to guess at what you are talking about. Existing original hair may continue to be lost to the balding process and even at 6 months shock loss can occur by accelerating the hair loss in the areas you are discussing. You doctor should have good photographs from just before your surgery to help you analyze what is actually happening. That is where you should get the answer to your question. Even if I saw you personally, I may not appreciate the changes you discussed above and the time line of those changes.

Tags: hair transplant, hairloss, hair loss, shock loss, density


Dear Dr. Rassman,

How dense can hair transplant be done assuming that there are plenty of donor area with thick hair and the target area still has 50% density? Can hair transplant be done in-between existing hairs to make the hair thick again?

Tried Propecia but stopped after 2 days because of side effects. I appreciate your help on the matter.

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You can transplant between existing hairs without difficulty, providing that the existing hairs are permanent and not miniaturized. I have seen patients receive very dense hair by transplanting between hairs that were previously transplanted.

Tags: hairtransplant, hair transplant, hairloss, hair loss, density, dense


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