Medically reviewed by Katelyn Hagerty, FNP
Written by Our Editorial Team
Last updated 6/7/2022
If you’ve started to notice the early signs of hair loss, it’s easy to wonder what’s causing you to shed hair.
Telogen effluvium and androgenetic alopecia are two common forms of hair loss. One causes temporary hair shedding that’s usually triggered by a specific event, while the other produces permanent hair loss that usually develops in a specific pattern.
While both forms of hair loss can look similar at first, their effects on your hair follicles are quite different. The good news is that both telogen effluvium and androgenetic alopecia are treatable with the right combination of habits and, if necessary, medication.
Below, we’ve explained what telogen effluvium is, as well as the effects that it can have on your hair’s thickness, density and general appearance.
We’ve also explained what androgenetic alopecia is, as well as what you may notice if you have this common type of hair loss.
Finally, we’ve covered the differences between telogen effluvium and androgenetic alopecia, as well as your options for treating both forms of hair loss and maintaining a full, thick head of hair at any age.
Telogen effluvium is a form of temporary hair loss that occurs when your hairs prematurely enter the telogen phase of the hair growth cycle.
Your hair constantly grows, rests and sheds as part of a multi-phase cycle. In a healthy person’s scalp, about 85 percent of all hairs are in the anagen phase of this cycle at any one time, during which the hairs grow to their full length over the course of several years.
Approximately 15 percent of hairs are in the telogen phase — a resting phase during which each hair stops actively growing and prepares to shed. Hairs that enter the telogen phase eventually fall out, only to be replaced by new hairs in the anagen phase.
Our guide to the hair growth process explains this process, which affects all hairs on your body, in more detail.
Telogen effluvium is triggered by sudden, severe stress on your body, which can affect your hair follicles and cause them to prematurely enter into the telogen phase.
A variety of factors can trigger telogen effluvium, including illnesses that cause fever, infections, severe trauma, surgery, fluctuations in your levels of certain hormones, medications and dietary issues such as iron deficiency, low protein intake or heavy metal ingestion.
Even severe stress can trigger hair loss from telogen effluvium, causing you to shed hair when you’re going through a difficult time in your life.
These events can suddenly move your hair follicles into the telogen phase, causing 70 percent or more of your hairs to stop actively growing. These hairs may rest for one to six months, then shed en masse, causing your hair to appear thin and lacking in coverage.
Telogen effluvium can have a major effect on your hair density, but it isn’t permanent. Once the causative factor has been identified, it’s typically possible to restore your normal hair growth by making certain changes to your lifestyle, habits and general health.
When androgenetic alopecia affects men, it’s referred to as male pattern baldness. This type of hair loss can also develop in women (referred to as female pattern hair loss), although it’s less common and usually less noticeable.
Androgenetic alopecia is caused by a mix of genetic factors and the effects of a hormone called dihydrotestosterone, or DHT.
DHT causes androgenetic alopecia by attaching to androgen receptors in your scalp. This can start a process called follicular miniaturization, in which your hair follicles become progressively smaller and spend less time in the anagen phase of the hair cycle.
Over time, your hair follicles can become so damaged that they’re no longer able to grow hairs that penetrate through your epidermis — the outermost layer of your skin.
Androgenetic alopecia usually starts near your frontal hairline, resulting in the classic receding hairline that many guys first spot in their 20s, 30s or 40s. Over time, it may affect almost your entire scalp, leaving behind a horseshoe-shaped pattern of hair.
Androgenetic alopecia and telogen effluvium are both common types of hair loss, although they have several key differences.
The first key difference is that androgenetic alopecia is a permanent form of hair loss, whereas telogen effluvium is a temporary type of alopecia. Put simply, hair that’s lost from androgenetic alopecia usually won’t grow back, whereas telogen effluvium shedding will eventually stop.
The second difference is that androgenetic alopecia and telogen effluvium typically cause very different types of hair loss, at least from an aesthetic perspective.
With androgenetic alopecia, it’s normal to notice some recession around your temples or other parts of your hairline, usually followed by a bald patch near the crown of your scalp.
Because there’s a genetic component to androgenetic alopecia, the precise pattern of hair loss can vary from one person to another. Dermatologists and other medical professionals often use the Norwood scale to assess the severity of androgen-related genetic hair loss.
With telogen effluvium, it’s more common to experience diffuse hair loss that affects your entire scalp fairly evenly, with your hairline intact and a reduced hair count producing a generally “thin” look to your hair.
The third difference is that androgenetic alopecia usually develops gradually over the course of years or decades, whereas telogen effluvium can often occur suddenly.
If you have androgenetic alopecia, you may notice your hairline slowly getting higher when you look at old photos of yourself and compare them to recent ones. Or, you might notice that some techniques for styling hair don’t provide the same frontal coverage that they previously did.
Telogen effluvium can come on much more suddenly. After a triggering event, your hair may go into a resting state for several months, only to suddenly fall out en masse a few months later as the proportion of anagen follicles goes back to normal.
The fourth difference is that although androgenetic alopecia can affect men of all ages, it’s most common (and usually most severe) in middle-aged and older men. As many as 50 percent of men are affected by age 50, with up to 80 percent affected by 70 years of age.
In comparison, telogen effluvium occurs in people of all ages, without a clear increase as people grow older. However, it’s more common in women than in men due to the severe, often sudden changes in hormone levels that can occur during and after pregnancy.
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Although they have different causes and can produce different symptoms, telogen effluvium and androgenetic alopecia also have several similarities:
Both conditions can cause hair shedding. Because telogen effluvium and androgenic alopecia are both forms of hair loss, they can both cause hair shedding beyond the usual 50 to 100 hairs you shed per day.
Both types of hair loss can cause thinning. Androgenetic alopecia generally begins at your hairline or crown, but it can also result in diffuse alopecia that makes the hair across your entire scalp appear thin and lacking in coverage.
Both forms of hair loss are treatable. Although losing hair from androgenetic alopecia or telogen effluvium can be frustrating, it doesn’t need to be permanent. Treatments are available for both forms of hair loss — a topic we’ve discussed more below.
Although androgenetic alopecia and telogen effluvium account for the majority of hair loss cases in men, they aren’t the only causes of hair loss. Other conditions that may cause permanent hair loss or temporary hair shedding include:
Traction alopecia. Traction alopecia is a form of permanent hair loss that’s caused by damage to the hair follicles from tight hairstyles. You may be more at risk of this type of hair loss if you wear your hair in styles such as dreadlocks or cornrows.
Tinea capitis. Tinea capitis is a form of scalp fungal infection that can cause hair loss. When the infection causes severe inflammation of the scalp (referred to as kerion), it may result in permanent damage to your hair follicles.
Alopecia areata. Alopecia areata is a form of patchy hair loss that’s associated with certain forms of autoimmune disease. It can cause round patches of hair loss and exclamation mark hair strands — hairs with narrowed hair roots and other growth defects.
Telogen effluvium is treatable. Usually, the treatment process involves identifying the underlying cause of the hair shedding, then taking steps to treat the medical condition and stop further hair loss from occurring.
If your healthcare provider suspects you have telogen effluvium, they may perform a hair pull test to check for signs of excess hair shedding. This test involves gently tugging on your hairs to see if a large number of loose hairs are shed at once.
If you have a positive hair pull test result, your healthcare provider may perform a scalp biopsy to identify the underlying cause of your hair loss.
Most of the time, telogen effluvium hair loss stops once the underlying problem is treated. You may need to take medication, correct a dietary imbalance or make changes to your lifestyle in order to limit stress in order to prevent shedding.
If your hair loss is caused by a specific medication, your healthcare provider may prescribe an alternative or adjust your dosage to prevent hair shedding.
Androgenetic alopecia is treatable with medication and surgery. Because this type of hair loss is permanent, it’s important to take action and consider treatment options as soon as possible after you notice the symptoms of hair loss developing.
Currently, the FDA has approved two medications as hair loss treatments: the prescription oral medication finasteride and the over-the-counter topical medication minoxidil.
Finasteride works by preventing your body from converting testosterone into DHT, the hormone that damages your hair follicles. This reduction in your DHT levels can slow down, stop or even reverse the effects of androgenetic alopecia on your hairline and scalp.
Numerous studies have found that finasteride works well as a hair loss treatment. In one, more than 90 percent of men with androgenetic loss of hair who took finasteride for 10 years showed signs of improvement in hair growth.
A separate study published in the Journal of the American Academy of Dermatology found that men with androgenetic alopecia who used finasteride over the course of two years experienced slower progression of hair loss and increased hair growth.
We offer finasteride online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.
Minoxidil works by moving your hair follicles into the anagen phase, or growth phase, of the hair growth cycle. It also stimulates blood circulation to hair follicles, which may trigger growth and supply your hair with extra nutrients.
Like finasteride, minoxidil is supported by a lot of scientific research. In fact, a study published in the journal Dermatologic Therapy found that it’s particularly effective when it’s used at the same time as finasteride.
In the study, researchers found that 94.1 percent of men with androgenetic hair loss who used both finasteride and minoxidil showed improvements over the course of 12 months, compared to 80.5 percent for finasteride on its own and 59 percent for minoxidil alone.
Hair transplantation is a surgical procedure that involves extracting hair follicles from the back and sides of the scalp (areas that are resistant to the effects of DHT), then moving them to the hairline, crown and other areas affected by male pattern baldness.
Getting a hair transplant may be an option worth considering if you have a receding hairline or other specific areas of hair loss that you’d like to address. This type of procedure can range in price from $4,000 to $15,000 or more based on the number of hairs to be grafted. There are several different kinds of hair transplants: Stem Cell Hair Transplant, NeoGraft Hair Transplants, FUT Hair Transplant, FUE Transplant, and if you are looking for non-surgical hair replacement, we have a guide for you, too.
Both telogen effluvium and androgenetic alopecia can cause you to shed hair. However, telogen effluvium usually involves temporary, diffuse hair loss, while androgenetic alopecia is permanent and typically develops as a receding hairline or bald patch.
If you’re starting to lose hair and want to seek expert help, you can take action by talking to your primary care provider, scheduling an appointment with a dermatologist in your area or using our range of easy, FDA-approved hair loss medications.
Interested in learning more about your options before you start? Our guide to finasteride for hair loss goes into more detail about how the most effective prescription medication for androgenetic alopecia works, as well as potential side effects that you should be aware of.