What Causes Hair Loss in Women?
Medically reviewed on March 8, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
While it’s not life-threatening, hair loss or hair thinning can be a trying ordeal for anyone. It can hurt your self-esteem and make you feel self-conscious, preventing you from going out and enjoying your life to its fullest. Social stigmas for hair loss still abound, which applies even more to women.
Hair loss is typically more common among men, but it can still affect women. Estimates suggest that about 50 percent of women experience some form of noticeable hair loss [1]. Hair loss can come in a few different forms in women. Learn more about the causes of female hair loss below and our available hormone test.
Understanding the Hair Growth Cycle
The average person sheds about 50 to 100 hairs per day. That can sound alarming, but that is a perfectly normal part of the hair growth cycle [1]. Your hair comprises two distinct structures. The follicle is the part that is rooted into your scalp. The “living” part of your hair lies at the base of each follicle. The second structure is the shaft, which is the part of the hair that you see, touch, and style daily [2].
Your hair grows about 0.3 to 0.4 millimeters per day. First is the anagen phase, which is the active growth phase. Cells in the root of the hair grow and divide rapidly, pushing up through the follicle. The catagen phase is the transition phase where active growth stops, and the hair is firmly attached to the root. During the telogen phase, your hair is at rest without active change. Hairs in this phase are known as “club hairs” and have completely stopped growing. Hairs toward the end of the telogen phase get shed and are replaced with new hairs [2].
The hairs on your scalp are all at different stages of this cycle, some shedding and others growing or transitioning.
Types of Hair Loss in Women
Hair loss is generally easy to spot, though it can be slow. If you notice your hair part widening, discover bald patches or thinning hair spots, or seem to have a lot more hair shedding in the shower, you may be experiencing hair loss.
Hair loss, scientifically known as alopecia, occurs in various forms, each with its specific causes.
Anagen effluvium
With anagen effluvium, hair loss occurs during the hair growth period. This typically occurs from using poisonous or toxic medications to a growing hair follicle, like chemotherapy or radiation therapy [1].
This form of hair loss is usually temporary. Hair typically grows back once the medication stops [1].
Telogen effluvium
On the other hand, telogen effluvium occurs at the end of the hair growth cycle. Telogen effluvium is characterized by many hair follicles reaching the telogen phase simultaneously, resulting in more hair falling out, forming bald patches throughout the scalp. A sudden traumatic, stressful event typically causes telogen effluvium [3].
Telogen effluvium is also usually temporary. Counseling support to manage stress and address the trauma can help [3].
Alopecia areata
Alopecia areata is a form of hair loss caused by an autoimmune disease affecting the skin. With this disease, the immune system mistakenly attacks the body’s hair follicles, causing damage to the follicles that prevent hair growth. This results in patchy bald spots on the scalp and potentially other body parts [4].
Traction alopecia
How you wear your hair can potentially contribute to hair loss in the form of traction alopecia. Hairstyles that pull at the scalp, like tight braids, ponytails, or cornrows, can cause stress to your follicles and scalp. Over time, as you continue to wear these hairstyles, you begin to pull hair out and cause damage to the hair follicle. Left untreated, you can potentially scar your scalp, resulting in permanent hair loss [5].
This process usually takes years. Along with hair loss, you may experience redness, irritation, and general tenderness in the scalp. More severe forms can result in blisters and red spots. This is also one of the few forms of hair loss among women that contribute to a receding hairline [5].
Androgenetic Alopecia
The most common form of hair loss among all genders is androgenetic alopecia, better known as male or female pattern baldness. Androgenetic alopecia affects about one-third of women in the United States [6].
In men, androgenetic alopecia typically starts at the top of the head (the crown) and the hairline. The hairline recedes while the hair on the crown begins to thin. The two eventually meet, resulting in the characteristic U-shaped band of hair around the sides and back of the head [6].
In women, androgenetic alopecia is a bit more subtle and comprehensive. Instead of any particular area balding or a receding hairline, female pattern baldness appears as thinning hair throughout the entire scalp [6].
What Causes Androgenetic Alopecia?
Androgenetic alopecia is caused primarily by hormonal imbalances, specifically elevated levels of dihydrotestosterone (DHT). DHT is an androgen, meaning male sex hormone, that has a similar structure to testosterone. An enzyme known as 5-alpha reductase converts testosterone into DHT [6].
An increase in DHT causes higher concentrations of androgen throughout the body. DHT causes hair follicles to shrink in the scalp, which cuts off oxygen and nutrients to the scalp. Shrunken hair follicles develop shorter anagen phases and extended telogen phases, resulting in more hair shedding without any hair regrowth [6].
An increase in androgens can come from various sources. You may have an underlying endocrine condition that contributes to excess androgen secretion. Most women also naturally produce less estrogen and more testosterone as they age [6].
While DHT and androgens are the main culprits for hair loss in women, genetics can play a role in the process. Specifically, genetics can contribute to sensitivity to androgen hormones resulting in hair loss. A woman without a genetic predisposition to this androgen sensitivity may maintain a full head of hair regardless of androgen levels [6].
If you experience hair loss and believe hormonal imbalances may cause it, consider getting your hormone levels tested. The Everlywell Women’s Health Test measures 10 key hormones involved with your overall health.
Treating Hair Loss
Some types of hair loss are temporary and may go away on their own, and for many other forms of hair loss, treatments are available to support hair growth. The most popular form of treatment for all types of hair loss is minoxidil. Initially developed as a treatment for high blood pressure, minoxidil is a topical treatment found to increase blood flow to the scalp. More blood to the scalp equates to more oxygen and nutrients to the hair follicles, which may help to support hair growth [6].
For androgenetic alopecia, women may also consider anti-androgen medication. This medication works by inhibiting the production of androgens, like testosterone and DHT, reducing their effects on the scalp. However, anti-androgen medications can come with some side effects, so consult your doctor [6].
Avoid hairstyles that require pulling your hair or otherwise stressing your scalp in terms of practical methods. Avoid products containing harsh chemicals that can damage your scalp or follicles.
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References
1. Hair Loss in Women. Cleveland Clinic. URL. Accessed March 8, 2022.
2. Physiology, Hair. StatPearls [Internet]. URL. Accessed March 8, 2022.
3. Telogen Effluvium. Harvard Health. URL. Accessed March 8, 2022.
4. Alopecia Areata. Cleveland Clinic. URL. Accessed March 8, 2022.
5. Billero V, Miteva M. Traction alopecia: the root of the problem. Clin Cosmet Investig Dermatol. 2018;11:149-159. Published 2018 Apr 6.
6. Treating female pattern hair loss. Harvard Health. URL. Accessed March 8, 2022.