Understanding the Impact of Hormones on Hair Health and Growth

Properly cared for grey hair can be beautiful!

The Impact Hormones Have on Your Hair

Hair is more than just a style statement; it reflects our overall health and well-being. Did you know that hormones can have a huge impact on your hair? Hormones can turn lustrous hair dry and dull, cause hair to fall out, and even straighten curly hair or vice versa! We will explore how different hormones can impact hair, the science behind these changes, and what you can do to help maintain healthy hair through hormonal shifts.

Scientists have identified more than 70 major hormones in our bodies. Just about all of them can affect hair. Hormones are the body’s chemical messengers and play a massive role in regulating the hair growth cycle, thickness, and texture. Different hormones dictate hair behavior differently depending on the body area and the individual's hormonal balance. We will focus on the primary culprits.

Key Hormones & Their Effects On Hair Shedding

Androgens (e.g., Testosterone & DHT): In scalp follicles, testosterone can convert into dihydrotestosterone (DHT), which shrinks hair follicles and shortens the hair growth cycle, ultimately leading to male and female pattern hair loss. However, on the face and body, androgens stimulate the growth of thicker, darker hair.

Estrogen: This hormone promotes healthy hair growth by prolonging the active growth phase (anagen). High levels during pregnancy often result in lush, thick locks, while the drop in estrogen during menopause often triggers hair thinning.

Thyroid Hormones: The thyroid sets the body's metabolic rate and heavily influences the hair follicle's life cycle. An underactive thyroid (hypothyroidism) or overactive thyroid (hyperthyroidism) can both disrupt this cycle, often resulting in diffuse hair thinning.

Cortisol: Known as the primary stress hormone, cortisol can be triggered by chronic stress, causing spikes that prematurely push hairs into the resting/shedding phase, leading to excessive shedding.

Insulin: Blood sugar imbalances and insulin resistance can disrupt the endocrine system, leading to increased testosterone production.

Prolactin: Affects the hair follicle cycle, with levels often fluctuating during pregnancy and the postpartum period.

Life Stages & Conditions That Can Affect Hair

Pregnancy: Surging estrogen prolongs hair in the growth phase, reducing shedding. After childbirth, plummeting hormone levels often lead to temporary, excessive shedding (postpartum hair loss).

Menopause: A drop in estrogen leaves androgens with a greater relative impact, causing scalp thinning and potentially new facial hair growth.

Polycystic Ovary Syndrome: A hormonal imbalance characterized by excess androgens. This frequently causes a contradictory pattern: scalp hair thinning alongside unwanted facial or body hair growth.

What Happened To My Curls?

The structural shift from straight to curly hair (or vice versa) is primarily driven by changes in estrogen, progesterone, thyroid hormones, and androgens. These hormones alter the shape of the hair follicle and the oil production of your scalp, turning genes that control your hair's texture on or off.

How Texture Shifts

Follicle Reshaping: Straight hair grows from perfectly round, symmetrical hair follicles, while curly hair grows from flat, asymmetrical, hook-shaped follicles. Hormonal spikes or dips can physically alter the shape of these follicles, causing them to twist or straighten.

Gene Activation: Many people carry a combination of both straight and curly hair genes. Shifting hormone levels can act as a genetic "switch," awakening a dormant curly-hair gene that causes a dramatic change in texture.

The Key Hormones Responsible

Estrogen: Often considered the ultimate "curl-friendly" hormone, estrogen supports the helical, curved shape of curly hair follicles.

Straight to Curly: A sudden drop in estrogen (like after giving birth or during perimenopause) changes the follicle shape, causing sleek hair to grow in wavy or curly.

Curly to Straight: Severe drops in estrogen (such as during menopause) can cause hair follicles to lose elasticity, leading previously bouncy curls to gradually straighten.

Androgens (Testosterone & DHT): These hormones alter follicle size and the protein structure of your hair. When estrogen drops and androgens become more dominant, the altered protein assembly can force straight hair to develop a coarse wave or curl.

Thyroid Hormones (Thyroxine & Triiodothyronine): Your thyroid directly manages keratin production, which is the foundational protein of hair. A thyroid imbalance alters how keratin proteins clump together, turning uniform, straight strands into irregular, frizzy waves.

Progesterone: This hormone works closely with estrogen to regulate sebum (oil) production on the scalp. Drops in progesterone severely dehydrate the hair follicle. Severe dryness naturally increases texture, prompting loose waves to tighten into distinct curls.

The Hormonal Culprits Behind Dry Hair

Estrogen and progesterone: The primary hormones responsible for keeping your skin and scalp plump, hydrated, and well-lubricated.

The Result: When these hormones plummet—most notably during perimenopause and menopause—sebum production takes a massive dive. Without natural oil, hair quickly becomes dry, frizzy, dull, and wiry.

Thyroid Hormone Deficiencies (Hypothyroidism): An underactive thyroid gland means your body is not producing enough thyroid hormones, which are responsible for regulating your entire metabolism.

The Result: This lack of metabolic support triggers a condition called trichodystrophy, causing hair to appear exceptionally dry, coarse, straw-like, and brittle. It also frequently causes a dry, flaky scalp.

Cortisol (The Stress Hormone): When you experience chronic stress, your adrenal glands flood your system with cortisol.

The Result: Without proper keratin structure and blood flow, the newly emerged hair lacks a smooth outer cuticle, causing it to lose moisture rapidly and feel rough and dehydrated.

When Do These Shifts Happen?

Puberty: The initial surge of estrogen and androgens can remodel childhood straight hair into adult curls almost overnight.

Pregnancy & Postpartum: The massive spike in estrogen during pregnancy, followed by a steep drop a few months after delivery, changes hair protein structure, permanently altering postpartum curl patterns.

Menopause: Plummeting estrogen and progesterone cause the scalp to dry out, causing curls to either lose their definition and flatten, or straight hair to unexpectedly wave. Hormones directly regulate the sebaceous glands (the oil glands attached to your hair follicles) and the cellular metabolism required to build strong, hydrated hair strands. When these hormones fluctuate or drop, your scalp reduces its natural oil production, leaving your hair parched and prone to breakage.

Steps to Help Your Hair

If a hormone shift is drying out your hair, standard surface conditioners might not feel like enough. You can support your hair health by:

Deep Moisturizing: Use topical oils like jojoba oil or argan oil, which closely mimic the molecular structure of natural human sebum to coat and protect dry strands. We recommend a good quality hair masque or hair serum.

Lower Wash Frequency: Wash your hair less often to preserve whatever limited oils your scalp is currently producing.

Seek a Medical Panel: Request a blood test from your doctor to check your TSH (Thyroid Stimulating Hormone), Free T3, Free T4, and Estradiol levels to address the root cause.

Balanced Diet: Nutrients like iron, zinc, biotin, and vitamins A, C, D, and E support hair growth.

Gentle Hair Care: Avoid harsh treatments and excessive heat styling that can weaken hair.

Manage Stress: Techniques such as meditation, exercise, and adequate sleep help regulate cortisol levels.