Hair Cycle: Implications for Hair Transplant

Dear friends,

in my last blog I discussed about hair cycle. Today I will show you the implications of this knowledge in the field of hair transplantation.

As we know, hairs are in a constant cycle, and individual hair is in a differe nt stage of this cycle at any given point of time. If we assume that a person has 3 year anagen / 4 month telogen cycle he will have 25% hairs each at 0-1 yr anagen, 1-2 yr anagen, 2-3 yr anagen, around 5% each at 1,2,3,4 mth telogen and around 5% in catagen. Although, this is oversimplification of the actual hair state, it illustrates the point well. Now, once these hairs (in various phases of hair cycle) are transplanted, it is natural for them to grow out at different points of time. Usually this growth occurs between 4^th to 12^th month post transplant but, the new hair can come out even beyond the traditional 1 yr mark.

Another implication is rate of hair growth. If the no. Of transplanted hair has more anagen component and less telogen, the results will be apparent sooner. This kind of pick and choose is possible for FUE, but not for strip. That is why people see good early results with FUE. During strip a fair amount of telogen hair will be transplanted. Once this hair completes is dormant stage and becomes active again, you will see the growth. So be patient.

Many people who are not properly trained or are not aware of the concept of hair cycle can contribute to hair wastage. Usually, the technicians who are cutting the graft (in old strip method) will discard a seemingly thin hair because they “thought” it was an insignificant, useless hair. This same hair would have grown into a perfectly healthy hair, given time and nourishment. I think that as a criminal wastage of hair in already depleted scalp.

Also, many a times technicians who do not use magnification can mistake a two hair graft, with one anagen and one telogen, as a single hair. If such hairs are used for frontal hair line or temple restoration, an unnatural tufty appearance may occur. FUE circumvents this problem because each graft is harvested by surgeon under magnified vision.

Hair Cycle: What is Anagen hair?

You may have read terms like anagen, catagen and telogen hair but did not know what they are. Here is the answer.

In human scalp growing hairs are in a constant cycle. There is an active growing phase, called anagen phase, a stable phase with steadily diminishing hair strength called catagen and a degenerative phase in which hair falls out, called telogen phase. This is followed by a dormant period at the end of which new hair come out and anagen phase restarts.
I hope, I have not confused you further. So here is a pictorial representation of this cycle,

An anagen hair is an growing hair. It keeps on increasing in length and is thick and strong. It is darker in colour and will give more volume to the mane. The anagen phase lasts for 3-4 years but may be as long as 10 years in some lucky individuals. On the other hand, in Catagen phase, the growth of hair is over but it is yet to fall out of the scalp. These hair are frayed, thinner, weaker and less pigmented. After the hair falls out,  the hair root goes into a resting phase for 2-3 months. This is called Telogen phase.  In a healthy scalp about 80% hair are in anagen phase, while 10% each are in catagen & telogen phase.

So what does this mean for you ? Basically it means that in a balding patient there are more telogen hair and less anagen hair. If we can increase the number of anagen hair or if we can change the ratio of anagen to telogen hair, more volume of hair can be generated from the same hair roots. Anti hair-loss medicines can prolong the duration of anagen phase and improve hair length and texture.

In my next blog I will discuss the implications of hair cycle in transplant patients.

What is FUE hair transplantation?

I assume that you already know the theory behind hair loss and hair transplant. There are two basic methods of harvesing donor hair. The conventional strip technique and follicular unit extraction. In Follicular Unit Extraction (FUE) technique donor hair are harvested one by one and is therefore more labour intensive. During this technique a small micropunch usually sized 1mm or smaller is used to isolate a group of hair from its skin attachments. These groups having one to four hair, called follicular units, are then gathered (pulled out) from the head. This leaves a pin point wound from the area of harvest.

In this way the hair are taken out one after another, until adequate number of hair required for that session have been harvested. This surgery is done at a "micro" level and requires 8X magnification and expert hand control. Since FUE procedure requires careful and delicate handling, it is possible to harvest only 1200-1500 follicular units per session. An average session may last 8 hours and may need to be repeated, if balding area or graft requirement is extensive. The donor wounds heal over the next of seven to ten days with barely visible scars. Stiches are not required

In contrast, in FUT (strip) technique all the required hair are removed in one long strip of hair bearing skin. These hair are then isolated from the strip and implanted. To close the gap after strip harvest, stiching is required.

After the grafts are harvested, micro slits are created in the bald area where these follicular units are implanted with help of fine instruments. Once they develop their blood supply they will give rise to healthy growing hair. The angulation of hair, density in key areas and hair design remais different from surgeon to surgeon and depends upon his experience and expertise.
At the end of the day the difference is only in harvesting technique, but what a big difference is that.

In my next blog, i will discuss the advantages and disadvantages of each technique.