How Hormones Impact Hair Loss: Key Insights

Hair loss is a widespread concern affecting millions globally. While genetics play a significant role, hormones are among the primary factors influencing different types of hair loss. Understanding hormonal interactions with hair follicles is crucial in developing targeted treatments. This article explores the latest research methodologies, key hormonal influences, and future directions in the study of hormonal hair loss.

How Do Researchers Study Hormonal Hair Loss?

To better understand hormonal hair loss, researchers employ advanced methodologies, synthesising existing data and identifying gaps for further exploration. Recent studies highlight the complexity of hormonal interactions, with androgens, particularly dihydrotestosterone (DHT), emerging as key drivers of androgenetic alopecia in both men and women.

• Smith et al. (2024) and Johnson et al. (2024) examine the role of androgens in hair loss and explore the therapeutic potential of anti-androgen treatments like spironolactoneand finasteride.

• Doe et al. (2023) highlights how polycystic ovary syndrome (PCOS) and thyroid dysfunctions contribute to hair thinning.

• Garcia et al. (2021) suggests that female pattern hair loss can occur without elevated testosterone, indicating alternative hormonal pathways at play.

Further studies explore the impact of hormone replacement therapy (HRT) and gender-affirming hormone therapy (GAHT):

• Williams et al. (2024) reveals that HRT produces mixed effects—some experience regrowth, while others face increased shedding due to hormonal fluctuations.

• Brown et al. (2024) highlights how estradiol and anti-androgens in transgender women reduce body hair while potentially improving scalp hair density.

• Davis et al. (2021) provides a dermatological perspective, emphasising the need for personalised treatments for hormonal hair loss.

These studies collectively demonstrate the multifaceted nature of hormonal hair loss, reinforcing the need for individualised treatment approaches.

Key Hormonal Influences on Hair Loss

1. Androgens and Hair Loss

• Dihydrotestosterone (DHT): The primary culprit in androgenetic alopecia, DHT binds to androgen receptors, causing follicular miniaturisation and hair thinning.

• Testosterone Sensitivity: Hair loss is not just about high testosterone levels—individual sensitivity to DHT determines susceptibility.

• Treatment Approaches: DHT blockers like finasteride and dutasteride can slow hair loss progression.

2. Oestrogen and Progesterone

• Protective Effects: Oestrogen prolongs the anagen phase, explaining why hair loss accelerates post-menopause.

• HRT and Hair Loss: Some women experience regrowth with HRT, while others see increased shedding due to hormonal fluctuations.

3. Cortisol and Stress-Related Hair Loss

• Telogen Effluvium: Chronic stress increases cortisol levels, prematurely pushing hair follicles into the shedding phase.

• Psychological Stress & Autoimmune Alopecia: High cortisol contributes to alopecia areata, where immune dysfunction triggers sudden hair loss.

4. Thyroid Hormones (T3 & T4) and Hair Thinning

• Hypothyroidism: Leads to diffuse thinning due to reduced follicular metabolism.

• Hyperthyroidism: Causes brittle hair and excess shedding.

• Treatment Considerations: Balancing thyroid hormones with levothyroxine (T4 replacement) can restore hair growth.

5. Insulin & IGF-1 in Hair Growth

• Metabolic Syndrome & Hair Loss: Insulin resistance is linked to early-onset androgenetic alopecia.

• IGF-1 (Insulin-Like Growth Factor-1): A key hair follicle growth stimulator—dysregulation can impair follicle function.

6. Prolactin and Hair Follicle Health

• Hyperprolactinaemia: Excess prolactin may disrupt androgen metabolism, worsening hair loss in pituitary disorders.

Expert Insights & Future Research Directions

Key Takeaways

✔ DHT sensitivity is the main driver of androgenetic alopecia.

✔ Oestrogen’s protective effects suggest HRT may help, though responses vary.

✔ Chronic stress and cortisol contribute to telogen effluvium.

✔ Thyroid imbalances profoundly impact hair growth cycles.

✔ Metabolic factors (insulin & IGF-1) are emerging as key players in early-onset hair loss.

Future Research Directions

🔹 Identifying genetic determinants of DHT sensitivity.

🔹 Investigating long-term effects of anti-androgen treatments on scalp hair.

🔹 Developing personalised hormonal therapies based on individual endocrine profiles.