Your Hair Is Always in Motion
It might seem like your hair just grows continuously, but each individual strand is actually cycling through distinct biological phases — growing, transitioning, resting, and shedding. Understanding this cycle helps explain why you see hair in the drain, why hair growth seems to plateau, and how your body's health directly affects what happens on your head.
The Four Phases of the Hair Growth Cycle
1. Anagen — The Growth Phase
This is the active growing period of a hair follicle. Cells in the bulb at the base of the follicle divide rapidly, producing new hair that pushes upward through the scalp. The anagen phase typically lasts 2 to 7 years, and its length is largely determined by genetics. The longer your anagen phase, the longer your hair can grow.
At any given time, roughly 85–90% of your scalp hairs are in the anagen phase. This is the phase most influenced by nutrition, scalp health, and hormonal balance.
2. Catagen — The Transition Phase
Lasting only 2–3 weeks, the catagen phase is a brief transitional period where the follicle shrinks and detaches from its blood supply. Hair growth stops, and the strand becomes a "club hair" anchored in the follicle. About 1–3% of hairs are in this phase at any time.
3. Telogen — The Resting Phase
During telogen, the follicle is dormant for approximately 3–4 months. The club hair remains in place while a new hair begins forming beneath it. Roughly 10–15% of scalp hairs are in telogen at any moment — this is normal.
Stress, nutritional deficiencies, hormonal shifts, and illness can push an abnormally large number of hairs into telogen simultaneously, causing the shedding event known as telogen effluvium — often noticeable 2–3 months after a triggering event.
4. Exogen — The Shedding Phase
This is the phase when the old club hair is shed. Losing 50–100 hairs per day is considered within the normal range. If you're seeing noticeably more than this consistently, it may be worth investigating potential causes with a healthcare professional.
What Affects Your Hair Growth Cycle?
| Factor | Effect on Cycle |
|---|---|
| Nutrition (iron, biotin, zinc, protein) | Deficiencies can shorten anagen and increase shedding |
| Chronic stress | Pushes follicles into telogen prematurely |
| Hormonal changes (pregnancy, thyroid) | Can dramatically shift cycle timing |
| Scalp health | Inflammation can disrupt follicle function |
| Genetics | Determines anagen length and overall density |
How to Support a Healthy Growth Cycle Naturally
- Eat a protein-rich diet: Hair is primarily keratin — adequate protein intake is non-negotiable for healthy growth.
- Address iron levels: Iron deficiency is one of the most common and overlooked causes of hair shedding, especially in women.
- Keep your scalp healthy: A clean, well-circulated scalp supports follicle function. Regular scalp massages with nourishing oils like rosemary or peppermint may encourage circulation.
- Manage stress: Chronic cortisol elevation is a known disruptor of the hair cycle. Sleep, movement, and mindfulness all play a role.
- Be patient: Even with optimal conditions, because of the cycle's timing, you may not see the result of a lifestyle change in your hair for 3–6 months.
When to See a Professional
If you notice sudden, dramatic shedding, thinning in patches, a receding hairline, or changes in hair texture without an obvious cause, consult a dermatologist or trichologist. Many causes of hair loss are treatable when caught early.