Normally, humans shed 50-100 hairs daily. Hair loss – or alopecia – occurs when the balance of the hair growth and shedding cycles is disrupted. Alopecia is a common medical condition affecting people of all sexes and ages. Although alopecia is a medical condition more generally associated with men, it is estimated that over 50% of women experience it, too. In 2015, the United States spent nearly 2.5 billion dollars on alopecia. Especially for women, hair loss can have significant psycho-emotional impacts, so getting to its root cause, treating, and reversing it is important. (15) 

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What Are the Stages of Hair Growth?

Humans have approximately five million hair follicles on their bodies and over one million follicles on their heads. Hair follicles are pores in the skin that surround the root and strand of a hair. Within the follicle, hair grows in a cyclical nature, which can be divided into three phases: anagen (growth), catagen (transition), and telogen (rest). (13) 

Understanding the hair growth cycle is important for various hair-related concerns, including hair loss and hair care, as it provides insight into the natural processes that govern hair growth and shedding. 

Anagen Phase

The anagen phase is the active growth phase of hair. During this stage, hair follicles are actively producing new cells that form the hair strand. Under normal circumstances, about 90% of follicles are in this phase simultaneously. This phase can last anywhere from two to seven years; the length of the anagen phase largely determines the length of an individual's hair. Hair grows approximately one centimeter per month. (5, 16) 

Catagen Phase

The catagen phase is a transitional phase that follows the anagen phase. During this short phase, which lasts about two to three weeks, the hair follicle shrinks and detaches from the blood supply. Only a small percentage of hair follicles, about 1%, are in the catagen phase at any given time. (5, 16) 

Telogen Phase

The telogen phase is a resting phase that follows the catagen phase that lasts approximately three to four months. The hair strand is fully formed during this stage but not actively growing. The old hair strand remains in the follicle while a new hair grows beneath it. At the end of the telogen phase, the old hair is shed, and the new hair takes its place. About 10-15% of your hair is in the telogen phase at any time. (16) 

What Causes Hair Loss in Women?

Hair loss in women can be caused by a variety of factors, both genetic and non-genetic. It's important to note that while some degree of hair loss is expected as people age, excessive or sudden hair loss may indicate an underlying issue. Here are some common causes of hair loss in women:

Hormonal Imbalances

Female pattern hair loss (FPHL), also known as androgenetic alopecia, is one of the most common causes of hair loss in women. It is characterized by gradual hair thinning at the crown of the head and a widening part. Hair follicles become smaller over time, resulting in finer, shorter, and less pigmented hairs. Genetics and androgenic hormones play a significant role in FPHL. (10) 

Hormonal changes during menopause are associated with shrinking of the hair follicle, hair loss, and hair thinning. As estrogen and progesterone levels fall, there is a relative rise in androgenic hormones (specifically dihydrotestosterone), which shrink the hair follicle and shorten the hair growth cycle. (7, 15) 

Postpartum hair loss is a common and temporary condition many women experience several months after giving birth. It occurs due to hormonal changes during and after pregnancy. During pregnancy, increased levels of hormones, particularly estrogen, can lead to a prolonged growth phase for hair. This results in thicker and fuller hair during pregnancy. However, hormone levels drop rapidly after childbirth, which can trigger the hair to enter the resting phase and fall out a few months later. (22) 

Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can lead to hair loss.

Nutrient Deficiencies

Iron deficiency is common in women with hair loss. Iron is vital for producing hemoglobin, which carries oxygen to your body's cells, including the hair follicles. Hair growth can be impaired when your body lacks iron, leading to hair thinning and shedding. (2, 6) 

Zinc is essential for the development and maintenance of healthy hair follicles. Brittle, dry hair and alopecia are common symptoms of zinc deficiency (2). 

B vitamins are essential cofactors for enzymes involved in energy metabolism and protein synthesis. Deficiencies in B vitamins riboflavin, biotin, folate, and vitamin B12 have been associated with hair loss. (2) 

Vitamin D modulates the growth and differentiation of keratinocytes. Vitamin D also acts as an immunomodulator; in this role, it is suspected that deficiency contributes to an increased risk of alopecia areata, an autoimmune form of hair loss. (2) 

Stress

Physical or emotional stress can disrupt the hair growth cycle, leading to hair loss. This type of hair loss is often temporary and is called telogen effluvium. 

Excessive pulling on the hair, as seen in tight hairstyles, can lead to a type of hair loss called traction alopecia (15). 

Exposure to harsh chemicals, such as those used in hair dyes, and overuse of hair treatments, such as excessive heat styling or perms, can also cause damage to the hair, leading to hair breakage and shedding (15). 

Functional Medicine Labs to Test for Root Cause of Hair Loss in Women

A standard evaluation for female hair loss should start with a thorough physical exam. Doctors should make note of the patient's hair distribution and density, appearance of the scalp, and perform a hair pull test. The hair pull test is done by grasping approximately 60 hairs close to the skin surface and applying steady traction as you slide your fingers along the length of the hair. A positive test, in which six or more hairs are plucked from the scalp, indicates active hair loss. (20) 

Functional testing can help identify hormonal and nutritional imbalances causing active and pathological hair loss. 

Thyroid Panel

A thyroid panel, consisting of TSH, free T3, and free T4, is a screening tool for hypothyroid and hyperthyroid states. Abnormal levels of TSH and thyroid hormones are diagnostic for thyroid disorders. 

Comprehensive Hormone Panel

A serum hormone panel measures the amount of estrogen, progesterone, and androgenic hormones in circulation to identify imbalances in reproductive hormones contributing to FPHL. Complementary to this panel is a comprehensive hormone panel, such as the DUTCH Plus, which measures sex and adrenal hormonal metabolites in urine and saliva samples to determine how hormones are synthesized and metabolized by the body. Collectively, these two types of hormone tests assist in assessing how endocrine disorders and chronic stress impact hair health and provide providers with valuable information for creating customized treatment plans to address the underlying hormonal issues.

Comprehensive Nutritional Assessment

Nutritional deficiency is a common problem in patients with hair loss. Amino acid, vitamin, and mineral deficiencies have been identified in 11-90% of patients with hair loss. A comprehensive nutritional assessment measures the levels of intra- and extracellular nutrients to screen for nutritional imbalances and guide dietary and supplemental treatment recommendations to optimize the diet.  

If these results indicate the presence of iron deficiency, ordering a complete iron panel and CBC to screen for iron deficiency anemia is recommended. 

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Functional Medicine Treatment for Hair Loss in Women

An effective hair loss treatment protocol targets the underlying cause of hair loss. This means that protocols and treatment options will vary drastically between individuals, depending on the type of hair loss they are experiencing and the external and internal factors contributing to the problem.

Specific to FPHL, topical minoxidil (Rogaine), oral spironolactone, and oral flutamide are effective medications for treating alopecia. However, side effects are reported with these medications, and hair loss often returns after they have been discontinued if the root cause hasn't been corrected. (20) 

Dietary Approaches to Treating Hair Loss in Women

Certain foods have been associated with an increased risk of hair loss. Excess amounts of sebum can lead to inflammation, harming hair and scalp health. Studies have suggested that diets rich in simple carbohydrates, fried foods, and red meat may contribute to hair loss by increasing sebum production. (29) 

As discussed above, hair loss can result from a diet lacking calories, protein, and micronutrients. Conversely, eating a balanced diet with sufficient protein, vitamins, and minerals is essential for hair growth (12). This 2020 study concluded that the Mediterranean diet is rich in protein and anti-inflammatory nutrients that promote hair health and advocated for its use as adjunctive therapy in treating alopecia disorders. 

Supplements & Herbs to Treat and Prevent Hair Loss in Women

Vitamins and minerals play a role in hair follicle development and are necessary for cellular growth. A high-quality multivitamin provides hair-essential nutrients, including vitamin A, vitamin D, vitamin E, and zinc. 

Natural approaches to treating FPHL include using botanical supplements that inhibit 5-alpha-reductase, the enzyme that converts testosterone to dihydrotestosterone. Black cohosh, chaste tree, green tea, licorice, saw palmetto, and spearmint have been shown to have anti-androgenic and DHT-reducing effects (11).  

Complementary and Integrative Medicine

Platelet-rich plasma (PRP) therapy involves drawing a small amount of the patient's blood, which is then processed to isolate the platelet-rich plasma. This plasma is rich in growth factors and proteins that stimulate hair follicles and promote hair growth. The PRP is then injected into the scalp in the areas of hair loss or thinning. PRP promotes the growth of thicker, healthier hair by increasing the activity of hair follicles. Studies show the efficacy of PRP injections for androgenetic alopecia. (18) 

Microneedling involves using a device with fine, tiny needles to create micro-injuries in the scalp. These micro-injuries stimulate the body's natural healing response, including increased blood flow and the production of collagen and growth factors. Topical treatments like minoxidil or PRP can be applied immediately after microneedling to enhance their absorption (8). (18, 25) 

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Summary

An intricate web of factors contributes to female hair loss. A functional medicine approach embraces identifying and addressing underlying imbalances, such as hormone fluctuations or nutrient deficiencies, to effectively promote hair regrowth and restoration. Dietary modifications, nutritional and botanical supplements, and natural medical aesthetic procedures can be used in conjunction with conventional treatment options to treat and prevent hair loss.