Genetics (Androgenetic Alopecia)

Genetics is the most common cause of hair thinning and loss. This condition is called Androgenetic Alopecia, also known as male or female pattern baldness. It affects millions worldwide and starts as a gradual thinning before turning into visible hair loss. For men, it often becomes noticeable in their 40s or 50s, but some experience it as early as their 20s. Women typically see hair thinning after menopause, though it can start in their 20s. If treated early, hair loss treatments may slow its progress.

Hormonal Changes 

Hormones play a key role in hair health. Changes from pregnancy, childbirth, menopause, or thyroid issues can lead to hair thinning or loss. Estrogen helps keep hair strong and shiny, but when levels drop, hair may thin. Dihydrotestosterone (DHT), a form of testosterone, is linked to hair loss, which explains why men experience it more often. Thyroid disorders also affect hair growth. An underactive thyroid (hypothyroidism) slows hair growth, while an overactive thyroid (hyperthyroidism) speeds up the cycle, leading to hair shedding.

Health Conditions

Certain illnesses, such as lupus, autoimmune diseases, infections, and anemia, can cause hair thinning.

Medications and Treatments

Some medications can affect hair growth. These include antidepressants, blood thinners, beta-blockers, anticonvulsants, hormonal medications, and immunosuppressants. Cancer treatments like chemotherapy and radiation often lead to temporary hair loss. The weight loss drug semaglutide, found in Wegovy and Ozempic, may also contribute to hair thinning.

Aging

As people age, hair growth slows. The anagen phase (growth phase) shortens, and the telogen phase (resting phase) lengthens. This means fewer active hair follicles, leading to thinner hair. Blood flow to the scalp also decreases with age, reducing the delivery of nutrients needed for strong hair growth. Sebum (oil) production also declines, which can make hair drier and more prone to breakage.

Stress and Hair Loss

Long-term stress can lead to Telogen Effluvium, a condition that pushes hair into the shedding phase too quickly. Stress also increases cortisol, a hormone that can disrupt the natural hair growth cycle.

Diet and Lifestyle

A poor diet can weaken hair. Low levels of iron, zinc, vitamins A, D, E, and B-complex (especially biotin) can lead to fragile hair that breaks easily. Protein is also key to hair growth. Without enough protein, the body prioritizes other functions over hair production. Lack of sleep, alcohol, tobacco use, and stress can also contribute to thinning hair.

Environmental Factors

Pollution, chemicals, and weather changes can harm hair health. Air pollution can clog hair follicles, while UV rays can weaken the scalp and hair cuticles. Humidity can cause frizz and breakage, while cold weather dries out the scalp. Even water temperature matters—water that is too hot or too cold can dry out hair. Harsh hair treatments like bleaches, dyes, and chemical treatments can also cause long-term damage, leading to breakage and hair loss.