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Hair Loss, Going Beyond Biotin

One of the most frustrating things for me to hear when helping patients address hair loss is "but I'm taking biotin". Like anything else when it comes to health, there is no one pill, one nutrient or one solution fix to hair loss. To effectively address hair loss we have to understand 1) how it grows and 2) what's causing it to fall out.

Hair, the basic facts

Hair grows 0.35mm per day[i] or 1.2cm per month and typically takes 6-12 months to complete a re-growth cycle. During this 6-12months a hair follicle goes through 3 phases[ii]:

  • Anagen: Growth phase lasting several years where the hair follicle works to produce the hair fiber.

  • Catagen: Transitional phase lasting a few weeks. During this phase, the hair follicle regresses and the base of the hair strand shrinks.

  • Telogen: Resting phase, where the hair follicle is dormant and no growth occurs. This can last up to 1 year. 10-15% of our hair is in this resting state at any given time.

Hair loss, common causes


Androgenetic or androgenic alopecia, is hair loss caused by a genetic tendency for hair follicles to be hyper-responsive to sex hormones, or for hormonal imbalance to affect hair follicles. Excessive hormonal stimulation of hair follicle tends to shorten its growth phase, and lead to thinner shorter hair follicles [iii].

This typically occurs in 50% of men by age 50 causing "male pattern baldness" where hair loss occurs at the top of and at the corners of the forehead. In women androgenic alopecia is very common and often appears as a widening hair part and general hair thinning.


Nutrients such as protein, vitamins and minerals are required for hair follicles to properly function[iv]. The two most common type of hair loss are androgenetic alopecia and telogen effluvium both of which have been associated with low vitamin D and/or low iron levels. Interestingly some studies show too much vitamin A or selenium can contribute to hair loss[v], so not all vitamins in large doses are beneficial.


Stem cells in the hair follicle are what help to regenerate hair cells. During the telogen (resting) phase these stem cells are inactive and recent research in mice show that certain stress hormones prolong the telogen phase inhibiting hair re-growth[vi]. Additional research shows that prolonged or severe stress can stop the growth phase pushing hair follicles prematurely into the telogen phase and exacerbate hair loss[vii].

Signs of stress related hair loss, known as “telogen effluvium” include:

  • Abrupt onset of hair loss occurring about 3 months following a major stressful event.

  • Generalized hair loss

  • Temporary hair loss, that can last month to years.

Other possible contributors to telogen effluvium include certain medications, severe illness (recent research shows COVID can trigger hair loss[viii]) and giving birth.


Known as “alopecia areata” this is hair loss caused by the immune system mistakenly attacking healthy hair follicles. Unlike hair loss caused by hormones, nutrient deficiencies or stress, alopecia areata causes significant hair loss in a specific area causing visible bald spots.

Alopecia areata seems to be more likely if you have a family member who has this condition, or if you have a history of eczema, thyroid disease, vitiligo, asthma and/or hay fever. Like other autoimmune diseases, low vitamin D levels are also suspected to be associated with alopecia areata.

Determining the root cause of your hair loss

When looking at the possible causes of hair loss, your doctor or ND may ask about:

  • Pattern of your hair loss (local or generalized)

  • Whether its falling from the root or breaking mid-shaft

  • Recent illness and medical history

  • Diet

  • Menstrual cycles

  • Sleep habits and stress levels

In addition, they may want to run lab tests which may include:

  • CBC (Complete Blood Count)

  • Ferritin

  • B12

  • Vitamin D

  • Thyroid hormones

  • Sex hormones

  • Stress hormones

Hair loss can be worrisome and confusing to address. If hair loss is stressing you out, schedule an appointment to understand what's causing or contributing to your hair loss and how it can be helped.

In health,



[i]Murphrey MB, Agarwal S, Zito PM. Anatomy, Hair. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: [ii]Hoover E, Alhajj M, Flores JL. Physiology, Hair. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: [iii]Ho CH, Sood T, Zito PM. Androgenetic Alopecia. [Updated 2022 Aug 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: [iv]Aksoy GG. Diffüz saç dökülmeleri; besinsel eksikler ve destekler/Diffuse alopecia; nutritional factors and supplements. Türkderm: Türk Deri Hastalıkları ve Frengi Arşivi= Turkderm: Turkish Archives of Dermatology and Venereology. 2014;48:45. [v]Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019 Mar;9(1):51-70. doi: 10.1007/s13555-018-0278-6. Epub 2018 Dec 13. PMID: 30547302; PMCID: PMC6380979. [vi]Choi S, Zhang B, Ma S, Gonzalez-Celeiro M, Stein D, Jin X, Kim ST, Kang YL, Besnard A, Rezza A, Grisanti L, Buenrostro JD, Rendl M, Nahrendorf M, Sahay A, Hsu YC. Corticosterone inhibits GAS6 to govern hair follicle stem-cell quiescence. Nature. 2021 Apr;592(7854):428-432. doi: 10.1038/s41586-021-03417-2. Epub 2021 Mar 31. PMID: 33790465; PMCID: PMC8923613. [vii]Arck, P.C. et al. (2003) Stress inhibits hair growth in mice by induction of premature catagen development and deleterious perifollicular inflammatory events via neuropeptide substance P-dependent pathways, The American Journal of Pathology. Elsevier. Available at:

[viii]Seyfi S, Alijanpour R, Aryanian Z, Ezoji K, Mahmoudi M. Prevalence of telogen effluvium hair loss in COVID-19 patients and its relationship with disease severity. J Med Life. 2022 May;15(5):631-634. doi: 10.25122/jml-2021-0380. PMID: 35815081; PMCID: PMC9262270.]


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