Male hormones, or androgens, significantly affect hair follicle enzymes and hair growth patterns. The primary androgen involved in hair loss is dihydrotestosterone (DHT), which is derived from testosterone. Here’s how male hormones interact with hair follicle enzymes and their effects
Key Enzymes
5-Alpha Reductase
The enzyme 5-alpha reductase is crucial in the conversion process of androgens
5-Alpha Reductase
This enzyme converts testosterone into DHT, which is a more potent androgen.
There are two main types of 5-alpha reductase
Type I
Found in various tissues, including the skin.
Type II
Predominantly found in the prostate and hair follicles.
Effects of DHT on Hair Follicles
Miniaturization of Hair Follicles
Process
DHT binds to androgen receptors in hair follicles, particularly in areas susceptible to androgenetic alopecia (male pattern baldness), such as the scalp.
Outcome
This binding causes the hair follicles to shrink or miniaturize over time, producing progressively thinner and shorter hairs. Eventually, the affected follicles may stop producing hair altogether.
Shortening of the Hair Growth Cycle
Anagen Phase
DHT shortens the anagen (growth) phase of the hair cycle, reducing the duration that hair spends growing. This results in hairs that do not grow as long or as thick.
Telogen Phase
The telogen (resting) phase becomes longer, meaning more hair follicles are in the resting stage rather than the growing stage, leading to increased shedding and thinning.
Alteration of Hair Follicle Function
Sensitivity
Hair follicles in certain areas of the scalp are more sensitive to DHT. This sensitivity is genetically determined, which is why pattern baldness often runs in families.
Regional Effects
The crown and frontal areas of the scalp are typically more affected, leading to the characteristic patterns of hair loss seen in male pattern baldness.
Impact on Hair Density and Quality
Reduced Hair Density
As follicles miniaturize and more enter the resting phase, overall hair density decreases.
Change in Hair Quality
The new hairs that grow are often finer and less pigmented, contributing to the appearance of thinning hair.
Management and Treatment
5-Alpha Reductase Inhibitors
Finasteride (Propecia)
Inhibits Type II 5-alpha reductase, reducing DHT levels and its effects on hair follicles.
Dutasteride (Avodart)
Inhibits both Type I and Type II 5-alpha reductase, leading to a more significant reduction in DHT.
Topical Treatments
Minoxidil (Rogaine)
Although not directly affecting DHT, it promotes hair growth by increasing blood flow to hair follicles and prolonging the anagen phase.
Natural Remedies
Saw Palmetto
Believed to have mild 5-alpha reductase inhibitory effects.
Pumpkin Seed Oil and Green Tea Extract
May contribute to reducing DHT levels naturally.
Conclusion
Male hormones, particularly DHT, play a significant role in hair follicle health and hair loss. The enzyme 5-alpha reductase facilitates the conversion of testosterone to DHT, which then binds to hair follicle receptors, causing miniaturization and shortened growth cycles. Understanding this process is essential for developing effective treatments for androgenetic alopecia and managing hair loss.