Which Hormone Causes Hair Loss in Females

Hair loss in women is often a sensitive subject, and while it is commonly associated with ageing or genetics, hormones also play a key role. Understanding which hormone causes hair loss in females can help make sense of why shedding happens and what can be done to manage it. Female hair loss can range from gradual thinning to more noticeable patches, and because hormones influence hair growth cycles, even small imbalances may trigger changes. The main hormone linked with hair loss in women is dihydrotestosterone, often referred to as DHT, but it is not the only one that plays a part.

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The Role of DHT in Female Hair Loss

DHT is a hormone derived from testosterone. Although testosterone is often thought of as a male hormone, women naturally produce it in smaller amounts. When testosterone converts to DHT, it can attach to hair follicles and gradually shrink them, making new hairs thinner and shorter. Over time, this process may lead to noticeable thinning, particularly around the crown and temples. This type of hair loss, known as androgenetic alopecia, is the most common form of hair loss in women and is largely driven by sensitivity to DHT.

Oestrogen and Hair Growth

Oestrogen is another hormone that has a big influence on female hair health. It helps to prolong the growth phase of the hair cycle, which is why many women notice thicker, shinier hair during pregnancy when oestrogen levels are high. However, when oestrogen levels fall, such as after childbirth or during menopause, hair can shed more easily. This drop in oestrogen also gives DHT more influence, which is why menopausal hair loss often follows a pattern of thinning rather than complete baldness.

Progesterone and Its Protective Role

Progesterone is often overlooked in discussions about hair health, but it plays a supportive role in balancing the effects of androgens like testosterone. When progesterone levels are healthy, they can help to counteract the conversion of testosterone to DHT. However, if progesterone levels fall, whether due to menopause, hormonal imbalances, or conditions like polycystic ovary syndrome (PCOS), women may experience more pronounced hair shedding.

Thyroid Hormones and Hair Shedding

The thyroid gland produces hormones that regulate metabolism, and imbalances in thyroid function can also contribute to hair loss. Both underactive and overactive thyroid conditions may disrupt the natural growth cycle of hair, causing it to thin across the scalp rather than in patches. This type of hair loss is usually temporary once thyroid levels are balanced, but it can still be distressing while it happens.

Stress Hormones and Their Impact

Cortisol, the primary stress hormone, does not directly cause hair loss in the same way as DHT, but prolonged stress can push more hair into the shedding phase of the growth cycle. This condition, known as telogen effluvium, often appears a few months after a stressful event and can make hair appear thinner all over the scalp. While cortisol itself is not the root cause, it does influence hormonal balance and overall hair health.

Collagen and Hormonal Hair Health

While hormones are the main drivers of female hair loss, supporting the structure of hair and the scalp can make a difference to overall resilience. Collagen provides amino acids that strengthen hair and may help improve scalp elasticity, creating a healthier environment for hair to grow. Although collagen cannot alter hormone levels or prevent genetic sensitivity to DHT, it can support stronger, shinier hair and may help counteract the brittle texture that sometimes accompanies hormonal changes.

Managing Hormone-Related Hair Loss

Identifying the hormonal trigger is key to managing female hair loss. For some women, this may mean treating an underlying thyroid condition or rebalancing hormones after pregnancy. For others, menopausal changes or PCOS may require longer-term support. While lifestyle choices such as eating a balanced diet, managing stress, and supporting the body with essential nutrients can help, professional guidance from a GP or dermatologist is important for persistent or severe hair loss.

Final Thoughts

The main hormone responsible for female hair loss is DHT, but oestrogen, progesterone, thyroid hormones, and even stress-related cortisol also play important roles. Hormonal changes throughout life can cause temporary shedding or longer-term thinning, and while this can feel worrying, understanding the cause is the first step toward managing it. Supporting your hair with good nutrition and collagen can help improve overall strength and appearance alongside medical advice where needed.