Many of you have probably heard of three stages of hair growth: anagen, catagen, and telogen. But there are actually four stages, and the fourth stage is exogen.
Understanding Hair Growth Stages
These stages are a cycle. The hair starts to grow, grows, rests, undergoes some follicle changes to prepare for shedding, and then falls out, and then the follicle starts the cycle anew. Every hair on your head is in a different stage of the cycle, although more of your hair (as much as 90% of it) is in a growth stage when you are younger and not suffering from any significant hair loss issues.
The anagen phase is the initial growth phase. It starts with the follicle moving down further into the scalp and getting connections with blood vessels (a capillary loop), nerves and connective tissue. A new hair starts to grow, and this hair will continue growing for between two (2) and eight (8) years (and occasionally much longer) depending mainly on your genetic profile. Some drugs like Rogaine (minoxidil) can lengthen the anagen phase. How much the hair grows is about 1 cm per month or between one-quarter (1/4) and one-half (1/2) inch per month, again depending on your genetics.
The catagen phase is a short two- to three-week transition phase that signals the end of the anagen (growth) phase. During this transition, the base of the hair changes form into a “club” hair and detaches itself from the blood vessels that have been nourishing it and the cells that have been adding to its length. When the club hair is completely formed, the hair enters the third or telogen phase.
The telogen phase is a resting phase. A fully dead and keratinized hair is the result of the telogen phase. This hair is resting and preparing to fall out. A body that is under a lot of stress, such as during pregnancy can send a lot of your hair into the telogen phase at the same time. In those circumstances, someone can notice a lot of hair loss occurring at the same time—such as after the birth of a child. The is called telogen effluvium.
The fourth and less often discussed stage is the exogen stage. New studies have shown that the exogen (shedding) phase is a distinct phase and that hairs in the anagen, catagen, and telogen phases are all firmly anchored in the scalp. Hairs in the exogen stage are actively shed from the scalp. In a normal healthy scalp, these shed hairs can be between 50 and 150 per day.
Hair loss starts to occur when these stages change their normal intervals. If the hair grows less in anagen or stops growing sooner than it used to, this can contribute to hair loss. Similarly, hair entering the catagen or telogen phase prematurely can accelerate hair loss. So, hair loss treatments can be directed at different stages of hair growth depending on what type of therapy you choose.
If you have any questions about treatment for hair loss or any of our products, we encourage you to call us directly at (844) 280-4680.