Seeing what seems like an excessive amount of hair in the shower or on your brush is a common experience that can cause concern. Many wonder why this occurs. This article explains the reasons for hair shedding, from normal biological processes to external factors.
Understanding Normal Hair Shedding
Hair shedding is a continuous and expected part of the hair’s natural growth cycle. Each hair follicle on your scalp goes through three main phases: anagen, catagen, and telogen.
The anagen phase is the active growth period, lasting two to eight years, with 85% to 90% of your hair in this phase. Hair follicles rapidly produce new cells, leading to hair lengthening.
Following the anagen phase, hair enters the catagen phase, a brief transitional period lasting two to three weeks. In this stage, hair growth slows, and the hair follicle shrinks and detaches from its blood supply.
The final stage is the telogen phase, a resting period that lasts for two to four months. During this time, the hair does not grow, and new hairs begin to form beneath the resting ones. The shedding of old hair then occurs to make way for the new growth. It is normal to lose between 50 and 150 hairs daily as part of this cycle, and this number can vary based on factors like age, genetics, and overall health.
Common Factors Causing Increased Hair Shedding
While some shedding is normal, an increase in hair coming out in the shower can be influenced by several common factors.
Stress
Physical or emotional stress can lead to a condition called telogen effluvium. Stress hormones disrupt the hair growth cycle, causing a larger number of hair follicles to prematurely enter the resting (telogen) phase. This increased shedding becomes noticeable two to three months after the stressful event.
Dietary Deficiencies
Dietary deficiencies can also impact hair health, as hair follicles require specific nutrients. Insufficient protein can weaken hair, potentially leading to increased shedding, as hair follicles are primarily composed of protein. Iron deficiency is another common cause of hair thinning, particularly in women, as iron is essential for transporting oxygen to hair follicles. Deficiencies in vitamins such as biotin (B7), vitamin D, vitamin C, and B12 can also disrupt the hair growth cycle and contribute to hair fragility and loss.
Hormonal Fluctuations
Hormonal fluctuations often play a role in increased hair shedding. Postpartum hair loss, for instance, occurs due to a sudden drop in estrogen and progesterone levels after childbirth. During pregnancy, elevated hormone levels prolong the hair’s growth phase, leading to thicker hair, but after delivery, many hairs enter the shedding phase simultaneously. During menopause, declining estrogen and progesterone levels, coupled with an increase in androgens, can cause hair follicles to shrink and result in thinning hair. Thyroid imbalances, whether an underactive (hypothyroidism) or overactive (hyperthyroidism) thyroid, can also lead to diffuse hair loss, as thyroid hormones are necessary for hair follicle development and maintenance.
Hair Care Practices
Certain hair care practices can also contribute to increased shedding. Harsh shampoos containing sulfates and parabens can strip the scalp of natural oils, leading to dryness and irritation. Excessive heat styling, such as frequent blow-drying or flat-ironing, can damage the hair’s outer layer, making it more prone to breakage. Tight hairstyles, like ponytails or braids, can cause traction alopecia due to constant tension on the hair follicles. Less frequent washing can lead to an accumulation of normally shed hairs, making it seem like more hair comes out on wash days.
When to Seek Professional Guidance
While some hair shedding is normal, certain signs indicate that professional guidance may be beneficial.
Consider a consultation if you experience a sudden or rapid increase in hair shedding over a short period. Noticeable thinning of hair, bald patches, or a receding hairline are also reasons to seek medical advice. These symptoms can suggest underlying conditions.
Consult a professional if hair shedding is accompanied by scalp symptoms such as itching, pain, redness, or scaling. These symptoms might point to a scalp condition or inflammation that requires specific treatment.
If your hair shedding does not improve after addressing common factors like stress or diet, or if you have other concerning symptoms alongside hair loss, a doctor can help determine the underlying cause. A dermatologist can diagnose the reason for hair loss through physical examination, hair pull tests, blood tests for deficiencies or hormonal imbalances, or a scalp biopsy if needed.