Estrogen is a hormone that plays an important role in the female body. It is responsible for the development of female secondary sex characteristics and regulates the menstrual cycle. Some of the visible effects of estrogen include breast and hip growth during puberty. However, estrogen also affects many tissues in the body that we cannot see, including hair and nails. In this article, we will explore the effects of estrogen on hair and nail growth in females.
How Estrogen Affects Hair Growth
Hair growth is regulated by many hormones, including estrogen. Estrogen receptors are present in hair follicles, showing that estrogen likely plays a direct role in the hair growth cycle. Here are some of the key ways that estrogen impacts hair:
– Estrogen prolongs the anagen (growth) phase of hair. Higher estrogen levels keep hair in the active growth phase longer before transitioning to the resting and shedding phases. This results in longer, faster growing hair.
– Estrogen increases hair follicle size. The size of hair follicles correlates with the thickness of each strand of hair. Estrogen causes hair follicles to increase in size, leading to thicker hair.
– Estrogen may prevent male pattern baldness in women. Male pattern baldness is related to the androgen hormone DHT. Estrogen may help counteract the effects of DHT on hair follicles in women, preventing male pattern baldness.
During puberty, rising estrogen levels in girls trigger faster hair growth. The high estrogen levels during pregnancy also cause increased hair thickness and growth rate. In contrast, post-menopausal women may experience thinning hair as estrogen levels decline with age. Estrogen deficiency is linked to hair changes in menopausal women.
Estrogen Effects on Hair Texture and Distribution
In addition to hair growth rate and thickness, estrogen also impacts hair texture and distribution on the body and scalp. Here are some key effects:
– Estrogen promotes scalp hair growth. The crown and frontal hairline have high numbers of estrogen receptors. Estrogen stimulates growth in these areas of the scalp.
– Estrogen causes finer, softer body hair. Body hair in women tends to be less coarse than in men due to estrogen effects.
– Estrogen redirects hair growth. Pubic and underarm hair develops during puberty under the influence of estrogen. Estrogen redirects hair to grow in the underarm and pubic areas of the body.
By promoting scalp hair growth and reducing body hair, estrogen produces the typical feminine hair distribution seen after puberty. Estrogen levels decline with menopause, leading to thinning scalp hair and coarser body hair.
How Estrogen Affects Nails
Like hair, our fingernails and toenails are also influenced by estrogen. Here are some of the key effects estrogen has on nails:
– Estrogen increases nail thickness and growth rate. Higher estrogen levels lead to faster nail growth and thicker nail plates.
– Estrogen improves nail strength and hardness. Nails become stronger and less prone to peeling and breakage when estrogen levels are optimal.
– Estrogen causes curvature of the nail plate. The nail plate grows outward more than upward during times of high estrogen, producing a curved nail edge.
– Estrogen promotes healthy nail bed vasculature. Estrogen supports blood circulation in the nail bed for a nourished nail matrix.
During pregnancy, elevated estrogen contributes to faster nail growth. On the other hand, post-menopausal women often report brittle, slow growing nails as estrogen levels fall. These estrogen effects help explain why nails tend to be healthier pre-menopause compared to post-menopause in women.
Role of Estrogen Receptors in Nails
Scientists have detected estrogen receptor proteins in the nails. This suggests that estrogen directly interacts with receptors to stimulate nail growth and health. Studies show the following:
– Estrogen receptor-beta is present in nail matrix and bed cells.
– Activity of this estrogen receptor increases during pregnancy when nails grow faster.
– Estrogen receptors decrease after menopause, corresponding with slower nail growth.
Activation of these estrogen receptors appears critical for optimal nail growth and strength. Decreased estrogen receptor activity post-menopause helps explain why many older women have thinner, more brittle nails.
Estrogen Interactions with Other Hormones
In addition to its direct effects, estrogen interacts with other hormones that influence hair and nails:
Androgens
Androgens like testosterone can counteract some effects of estrogen:
– Androgens promote scalp hair loss and body/facial hair growth in both men and women. Estrogen helps offset these effects in women.
– Post-menopause, the balance shifts towards androgens as estrogen levels fall. This contributes to scalp hair thinning and coarser body hair in older women.
Progesterone
Progesterone works synergistically with estrogen:
– Progesterone enhances estrogen’s growth-promoting effects on hair during pregnancy.
– High progesterone also contributes to increased nail growth and decreased hair shedding during pregnancy.
– Low progesterone relative to estrogen may exacerbate hair loss conditions like female pattern hair loss.
Growth Hormone
Growth hormone directly stimulates hair growth:
– Estrogen increases growth hormone levels by promoting its secretion from the pituitary gland.
– Through this interaction, estrogen helps optimize growth hormone’s beneficial effects on hair.
– Excess growth hormone can lead to increased body and facial hair growth in women, an androgenic effect.
Thyroid Hormones
Thyroid hormones regulate the hair growth cycle:
– Estrogen enhances the effects of triiodothyronine (T3), the active thyroid hormone.
– This interaction between estrogen and thyroid hormone results in prolonged hair growth.
– Low thyroid function (hypothyroidism) can contribute to hair thinning and brittle nails.
Key Points
In summary, here are the key takeaways about estrogen effects on hair and nails:
– Estrogen prolongs the active hair growth phase and stimulates faster, thicker hair via direct effects on hair follicles.
– Estrogen promotes scalp hair growth while reducing coarse body and facial hair in women.
– Estrogen thickens the nail plate, accelerates nail growth, and strengthens nails through actions on nail matrix cells.
– Estrogen interacts with other hormones including androgens, progesterone, growth hormone, and thyroid hormone to regulate hair and nails.
– Decreased estrogen after menopause contributes to thinning hair, increased facial/body hair, and brittle nails in older women.
The Impact of Estrogen-Containing Medications
Medications that contain or modulate estrogen can also impact hair and nails. Here are some examples:
Birth Control Pills
Birth control pills contain estrogen and progesterone. Effects on hair include:
– Increased scalp hair thickness and growth rate.
– Decreased hair shedding resulting in fuller hair.
– Potential for increased body and facial hair in some women.
Effects on nails include:
– Faster nail growth.
– Stronger nails less prone to splitting and chipping.
Hormone Replacement Therapy
Estrogen given as part of hormone replacement therapy can:
– Promote scalp hair growth in postmenopausal women with thinning hair.
– Reduce facial and body hair growth.
– Increase nail thickness and growth rate.
However, effects vary depending on the dose, route of administration, and whether a progesterone is also given.
Estrogen Blockers
Medications that block estrogen’s effects may have the opposite impact:
– Estrogen blockers used for breast cancer can cause hair thinning and loss.
– Reduced estrogen action may also contribute to brittle, slow growing nails.
The impacts vary based on the medication used and how much estrogen is inhibited. Effects are usually temporary with improved hair and nails after discontinuation.
Role of Estrogen in Hair and Nail Disorders
Abnormal estrogen levels or responses can contribute to certain hair and nail disorders:
Hair Loss Conditions
– Female pattern hair loss is linked to estrogen deficiency in the scalp. Topical estrogen may help counteract this.
– Postpartum hair loss is temporary increased shedding caused by the estrogen drop after pregnancy.
– Estrogen deficiency worsens hair loss in women with alopecia areata, an autoimmune disorder.
Brittle Nail Conditions
– Onychorrhexis (longitudinal nail splitting) is associated with low estrogen levels in postmenopausal women.
– Estrogen improves brittle nail condition secondary to thyroid disorders like hypothyroidism.
Optimizing estrogen status improves hair and nail conditions related to estrogen deficiency. However, estrogen excess can also cause hair loss in some women due to interactions with androgens. The optimal estrogen level is different for each woman.
Role of Diet and Environmental Factors
Diet, medications, and environmental factors can modulate estrogen levels and alter its effects on hair and nails:
Diet
– Phytoestrogens from soy, other legumes, and herbs can mildly increase estrogen activity. However, studies on their effect on hair are lacking.
– Diets high in processed carbohydrates and sugar lead to increased insulin. This reduces sex hormone binding globulin resulting in more free estrogens.
– Being overweight or obese increases conversion of androgens to estrogen in fat tissue, altering the androgen-estrogen balance.
Medications
– Hormonal contraceptives provide exogenous estrogen and progesterone.
– Hormone replacement therapy, estrogen blockers, and modulators also dramatically alter estrogen levels and activity.
– Other prescription drugs may indirectly increase or decrease estrogen levels.
Environment
– Chemicals with estrogen-like effects are widespread environmental contaminants and may alter estrogen activity in the body. However, strong evidence linking this to hair and nail changes is lacking.
While these factors can influence estrogen levels, we need more research on whether they significantly impact hair or nails. In many cases, the effects are likely small or inconclusive.
Conclusion
Estrogen exerts a wide range of effects on hair follicles and nail beds. Optimal estrogen levels promote faster, thicker hair growth on the scalp along with stronger, healthier nails. Estrogen also interacts with other hormones to coordinate their effects. Changes in estrogen levels during a woman’s life cycle correlate with hair and nail characteristics at different stages from puberty through menopause. Disruptions in normal estrogen signaling contribute to certain hair and nail disorders predominantly in women. While many details are still being elucidated, the evidence clearly demonstrates estrogen is a major regulator of hair and nail growth and properties in females.