Hair loss is a normal part of the hair growth cycle. Most people shed between 50 and 100 hairs per day as part of natural renewal. However, many individuals experience periods of noticeably increased shedding at least once in their lifetime. Understanding the underlying causes can help reduce worry and guide you toward appropriate solutions. In many cases, hair loss is temporary and reversible once the contributing factor is identified.
Below is an overview of the most common causes of hair loss and how they influence the hair growth cycle.
Hormonal Causes
Hormones play a major role in regulating hair growth, and imbalances can lead to thinning or shedding in both men and women.
A well‑known hormonal cause is androgenetic alopecia, a hereditary condition influenced by the hormone DHT (dihydrotestosterone). DHT binds to androgen receptors in hair follicles, causing gradual miniaturisation. In men, this follows a predictable pattern from the hairline to the crown. In women, thinning is more diffuse and does not follow a set pattern.
Not everyone with DHT experiences hair loss; susceptibility depends on the number and sensitivity of androgen receptors in the follicles. Current treatments often focus on reducing DHT’s impact, and future developments may include gene‑based therapies.
Thyroid Disorders (Overactive or Underactive Thyroid)
An overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid can significantly affect hair health. Thyroid hormones help regulate the hair growth cycle, and when levels are too high or too low, follicles may prematurely enter the resting phase.
This can lead to diffuse thinning across the scalp rather than patchy loss. Once thyroid levels are medically stabilised, hair growth typically improves. Anyone experiencing hair loss alongside symptoms such as fatigue, weight changes, or temperature sensitivity should seek medical evaluation.
Childbirth
Many women experience increased shedding after giving birth. During pregnancy, elevated estrogen levels keep hair in a prolonged growth phase. After delivery, hormone levels return to normal, causing many follicles to shift into the resting (telogen) phase simultaneously.
This type of hair loss typically begins two to three months postpartum and resolves naturally within six months.
Birth Control Pills
Women who are genetically predisposed to androgenetic alopecia may notice increased shedding when starting or stopping certain birth control pills. Hormonal fluctuations can trigger temporary thinning.
Individuals with a family history of hair loss should consult a healthcare professional before beginning hormonal contraception. While shedding usually resolves within several months, some women may not fully regain the hair lost during this period.
Nutritional Deficiencies
A balanced diet is essential for healthy hair growth. Insufficient protein intake or irregular eating habits can push hair follicles into the resting phase, leading to increased shedding. If hair can be easily pulled out from the root, inadequate nutrition may be a contributing factor.
Improving dietary habits and ensuring adequate protein and nutrient intake can help restore normal growth.
Low Iron Levels
Iron deficiency is a common cause of hair loss, particularly in women during menstruation. When the body lacks sufficient iron, hair follicles may not receive the nutrients they need to function properly.
A simple blood test can identify low iron levels. Increasing dietary iron or using supplements under medical guidance can help correct the issue.
Disease or Illness
Temporary hair loss can occur after illnesses such as severe infections, high fever, thyroid disorders, or chronic medical conditions. Surgery and certain medications—including chemotherapy—can also disrupt the hair growth cycle.
In most cases, hair regrows once the underlying condition is treated or the medication course is completed.
Final Thoughts
Hair loss can be caused by a wide range of factors, many of which are temporary and reversible. Understanding the reason behind your shedding is the first step toward finding an effective solution. A nutritious diet, stress management, and professional guidance can support healthy regrowth. For persistent or severe hair loss, consulting a qualified healthcare professional or dermatologist is essential for accurate diagnosis and appropriate treatment.