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A Close-Up Look on Hair Follicle Anatomy

Whether you’re investigating laser hair removal options or you’re simply curious about how your body works, understanding the structure of the hair follicle and the hair growth cycle is enlightening. In this blog post, we will delve into the world of hair follicles, their growth phases, and how these factors impact the laser hair removal process.


Hair follicles are tiny, tube-like structures located in the dermis, the layer of skin beneath the surface (epidermis). Each follicle contains a hair bulb at its base, where actively dividing cells build the hair shaft. Surrounding the hair bulb is a complex structure involving blood vessels (providing nutrients), sebaceous glands (providing oils), and the papilla (delivering the blood supply to the hair).

Packed into each follicle are two types of melanin, the pigment responsible for the color of our hair and skin: eumelanin (black or brown) and pheomelanin (yellow or red). The concentration and ratio of these melanin types determine the color and tone of your hair.

The Hair Growth Cycle: An Ever-Changing Journey

Understanding Hair Follicle Growth PhasesWhen addressing treatments related to hair, whether it’s hair removal or combating hair loss, a fundamental understanding of hair follicle growth phases is essential. This is because the success of many treatments largely depends on targeting specific phases of hair growth.

  1. Anagen (Growth Phase): This is the active growth phase of hair follicles. Hair shafts are produced during this phase, which can last for several years. Most of our hairs (about 85-90%) are in this phase at any given time. Treatments like laser hair removal are most effective during the anagen phase because the hair is directly connected to the follicle, allowing the laser to target and destroy the follicle effectively.
  2. Catagen (Transition Phase): Following the anagen phase, hair enters the catagen or transitional phase. This phase is relatively short, lasting only a couple of weeks. During this time, the hair stops growing and detaches from its blood supply. The hair follicle starts to shrink in preparation for the resting phase.
  3. Telogen (Resting Phase): During the telogen phase, the hair is fully at rest, and no new growth occurs. This phase can last for several months. Eventually, the resting hair will fall out, and new hair will begin to grow in its place, starting the cycle over again with the anagen phase. Hair loss treatments often aim to move hairs from the telogen phase back into the anagen phase.
  4. Exogen (Shedding Phase): This is when the hair sheds and the follicle goes back to the anagen phase to start the process all over again. It’s normal to lose 50 to 100 hairs per day during this phase.
Hair Growth Cycle
Hair growth cycle infographics

The Importance of Recognizing Hair Growth Phases in Treatments

The intricate nature of hair growth cycles is the backbone behind the success of various hair-related treatments. Let’s delve deeper into its significance:

Laser Hair Removal

This procedure primarily targets the melanin in the hair. Since the anagen phase is when the hair is actively growing and is most densely packed with melanin, lasers are most effective during this period. However, given that all hair isn’t in the same growth phase at once, multiple sessions are required to catch each hair in its anagen phase. This staggering treatment ensures that the maximum number of hair follicles is effectively targeted over time, leading to more comprehensive results.

Hair Loss Treatments

Hair loss or thinning may occur when an unusually large number of hairs enter the telogen or resting phase and fewer hairs remain in the growth or anagen phase. By understanding these cycles, treatments can be tailored to either prolong the anagen phase, shorten the telogen phase, or stimulate the hair follicles to enter the anagen phase faster. Therapies such as topical minoxidil, for instance, aim to prolong the anagen phase, resulting in longer, denser hair.