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What Causes Sudden Hair Loss in Men?

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Steph Coelho

Published 04/20/2021

Updated 07/26/2024

Suddenly seeing handfuls of hair swirling in the shower drain can be stressful. And if it’s happening to you, you’re probably wondering what causes sudden hair loss in men. There are many reasons this could happen, and luckily, many are temporary.

Regardless of why you’re losing hair, you’re not alone. Hair loss is a common concern for many men.

Gradual hair loss due to androgenetic alopecia (AKA male pattern baldness) affects up to 50 percent of men by the time they turn 50. But this type of hair loss comes on slowly, meaning you’ll likely have time to notice the signs of balding.

On the other hand, rapid hair loss happens quickly and isn’t usually the result of male pattern hair loss. Read on to learn about rapid hair loss causes in men, plus what you can do to prevent hair loss and stimulate hair regrowth.

Shedding is a natural part of the hair growth cycle — it’s normal to lose between 50 to 100 hairs a day, according to the American Academy of Dermatology (AAD).

You’ll know you’re experiencing hair loss when you see much more hair than usual in your comb, pillow, or shower.

As we mentioned, male pattern baldness is a common cause of hair loss and causes permanent hair loss around the hairline, crown, or entire scalp.

But if you’re experiencing sudden hair loss, you may actually be experiencing a different type of baldness. Various factors, including medical conditions, can cause rapid hair loss, but male pattern baldness usually doesn’t.

The good news is that some common causes of rapid hair loss cause temporary hair shedding, meaning your hair will gradually grow back after treating the underlying issue.

Below, we break down hair loss causes that could lead to your hair rapidly falling out.

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Male Pattern Baldness (Androgenetic Alopecia)

What causes hair loss in men? Male pattern baldness, also called androgenetic alopecia, is the most common culprit.

This type of hair loss is usually gradual. You may first notice a receding hairline, then months or even years later, that thinning hair could lead to a bald spot — it’s rarely the type of rapid hair loss that likely brought you here.

Androgenetic alopecia results from a combination of genetic and hormonal factors.

All men have the male steroid hormone known as dihydrotestosterone (DHT). DHT produces male genitalia in fetal development and is responsible for the body hair, facial hair, and deep voice that develop during puberty.

As you get older, DHT can also shorten the hair growth cycle. It attaches to receptors in hair follicles, causing shrinking or hair miniaturization. This ultimately leads to hair thinning and baldness.

As for the genetic factors, some people are more sensitive to the effects of DHT than others — and that level of sensitivity can be passed down through families.

Get the full scoop in our guide to DHT and male hair loss.

Telogen Effluvium

Stress doesn’t directly cause balding, but stress hair loss is real.

Telogen effluvium is a common type of hair loss typically triggered by stress, illness, or any major shock to the system. It occurs when hairs that should be in the growth (anagen) phase suddenly enter into the resting (telogen) phase of the hair growth cycle.

When most of your hair stops growing due to stress or illness, it may fall out all at once. This leads to sudden hair loss and visible diffuse thinning.

Unlike male pattern baldness, which usually causes hair loss around the hairline or crown, hair loss from telogen effluvium typically affects your entire scalp.

Beyond significant stress, like losing a job or the death of a loved one, other factors that can cause telogen effluvium include:

  • Illness, severe infection, or surgery

  • High fever

  • Sudden weight loss, especially of 20 pounds or more

  • Some types of medication, like beta-blockers or anticoagulants

  • Hormonal conditions like hypothyroidism (underactive thyroid)

  • Certain autoimmune disorders, particularly those affecting the thyroid (like Hashimoto’s and Graves’ disease)

Although telogen effluvium hair loss can happen abruptly, it may take several months after the triggering event or illness before you see hair loss.

The good news? Telogen effluvium is temporary and usually resolves after the underlying issue is addressed.

Tinea Capitis (Scalp Ringworm)

Tinea capitis (scalp ringworm) is a type of scalp fungus that causes your skin to become red, itchy, dry, and cracked.

Scalp ringworm could make you shed hair. When this type of infection is severe, it can cause a permanent form of hair loss called scarring alopecia, which appears as one or more bald patches.

Tinea capitis is most common in children and teens but can develop at any age. In addition to affecting the scalp, it may spread to your eyebrows and eyelashes.

Since it’s a fungal infection, tinea capitis is typically treated with oral antifungal medications and antifungal shampoo.

Nutritional Deficiencies

Hair follicle cells are the most rapidly dividing cells in the body, so growing hair requires lots of energy.

If you’re not getting enough energy from food, your body won’t have the fuel it needs to grow hair.

A consistently poor diet or a condition like iron deficiency anemia could trigger hair fall.

Vitamin deficiencies that may cause hair loss include:

  • Iron

  • Ferritin

  • Niacin

  • Zinc

  • Fatty acids

  • Selenium

  • Vitamin D

  • Vitamin A

  • Vitamin E

  • Folic acid

  • Amino acids

  • Biotin

We should note a biotin deficiency is rare — most people get enough of the B vitamin from the foods they eat.

If you’re rapidly losing hair, taking action as soon as possible may help prevent further hair loss.

Since hair loss has several possible causes, it’s best to talk to an expert to figure out the likely cause of your hair loss.

Here are a few potential next steps:

  • Talk to your healthcare provider. Can hair loss be a sign of something serious? In some cases, yes. If you think your hair loss may be related to an underlying health issue, reach out to your primary care provider for assistance.

  • Contact a dermatologist. Dermatologists specialize in skin and hair conditions, including scalp issues like hair loss. If you’re losing hair rapidly, a dermatologist can examine your scalp and provide a diagnosis.

  • Consider hair loss treatments online. If you’d rather skip an in-person visit, you can talk to a healthcare provider online about treatments for hair loss.

A healthcare professional can help identify what’s causing your rapid hair loss, whether it’s stress, nutrition, or something else.

They may perform blood tests to see if a hormonal imbalance is causing excessive hair loss, check if you have thyroid disease, or screen for other autoimmune conditions.

Your provider can also tell you if medication side effects could be contributing to hair loss.

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Fortunately, there are things you can do to slow or reverse rapid hair loss and male pattern baldness.

Based on the cause of your hair loss, your healthcare provider may suggest one or several of the following treatment options.

Treat Underlying Conditions

When it comes to treating rapid hair loss, it’s important to understand the problem before finding the solution. This could mean assessing your daily stressors or exploring whether an illness or medication may be causing hair loss.

Illnesses that cause hair loss include:

  • Certain fungal infections

  • Trichotillomania (TTM), an impulse disorder that causes hair pulling

  • Autoimmune diseases (especially those affecting the thyroid) that cause alopecia areata

  • Eating disorders that cause nutritional deficiencies

  • Skin disorders that cause excessive scratching of the scalp

Medications that may cause hair loss include:

  • Chemotherapy drugs

  • Beta-blockers

  • Statins

  • Certain blood thinners

  • Certain antidepressants

Talk to your healthcare provider if you have (or think you may have) any of the above conditions, and let them know if you’re taking any medication. Once you get a diagnosis, you can get the proper treatment.

Finasteride

Finasteride (also known by its brand name, Propecia®) is a prescription treatment proven to slow hair loss and stimulate new hair growth.

Remember DHT, the hormone partially responsible for male pattern baldness? Finasteride reduces the amount of dihydrotestosterone in the body.

Along with minoxidil, it’s one of the only treatments approved by the Food and Drug Administration (FDA) for hair loss.

Minoxidil

Minoxidil (also sold as Rogaine®) is proven effective for treating hair loss. This treatment is sold over the counter as minoxidil foam or liquid minoxidil solution, both of which are easy to apply.

If you had a previous reaction to the liquid option, the foam could be a better choice, as it doesn’t contain propylene glycol. Either way, only apply minoxidil to areas of the scalp with hair loss.

Topical Finasteride & Minoxidil Spray

Using a topical combination of topical finasteride & minoxidil spray may produce better results than using either medication alone. That’s because finasteride and minoxidil have the same goal but work in different ways.

Finasteride blocks DHT, and minoxidil is a vasodilator. This means it brings blood flow to the scalp along with nutrients and oxygen, moving hair follicles into the active growth phase of the hair growth cycle.

Habits and Lifestyle Changes

Making some lifestyle changes may help treat rapid hair loss — or at least make hair appear fuller while you wait for your hair to grow back in.

Here’s what you can try:

  • Take your vitamins. Supplements like biotin gummies can be beneficial for people with deficiencies. Hair is primarily made up of keratin, and biotin helps the body produce this protein.

  • Use hair-thickening shampoo. Our over-the-counter volumizing shampoo and volumizing conditioner for men contain a blend of biotin, caffeine, and linden berry extract to lift hair from the roots so it looks fuller and feels stronger.

  • Explore saw palmetto. Saw palmetto is a plant extract that may reduce DHT uptake by the hair follicle and slow hormone-related hair loss like androgenetic alopecia (sometimes called androgenic alopecia). Our thickening shampoo with saw palmetto is an easy way to incorporate this ingredient into your everyday routine.

  • Go easy on your scalp. If you wear tight hairstyles like braids or ponytails, you may experience a type of temporary hair loss called traction alopecia. Giving your scalp a break from tight styles can help reduce patchy hair loss.

Hair loss treatments, delivered

What causes rapid hair loss? Here’s a quick recap:

  • Rapid hair loss can happen for many reasons. Besides hereditary male pattern baldness, rapid hair loss might occur due to nutritional deficiencies, certain illnesses, side effects of medications, or stress.

  • It’s crucial to seek medical advice as soon as possible. A healthcare professional can identify the root cause of your hair loss and make hair loss prevention recommendations. While rapid shedding is usually temporary, you may want to ask your provider about medical treatment options like hair transplants for more severe hair loss.

  • Consider FDA-approved hair loss treatments. You can protect your hair and stimulate regrowth with hair loss medication, such as minoxidil or finasteride. You can also try taking hair loss vitamins or using products designed to make your hair look fuller.

One of the best ways to avoid rapid hair loss is to catch it early.

Our guide to the early signs of hair loss goes into detail about what you might notice if you’re starting to lose your hair.

14 Sources

  1. AAD. (n.d.).Do you have hair loss or hair shedding? Retrieved from https://www.aad.org/public/diseases/hair-loss/insider/shedding
  2. Ho, C., Sood, T., Zito, P. (2022, Oct). Androgenetic Alopecia. StatPearls Internet. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK430924/
  3. Kinter K., Anekar A. (2023, March). Biochemistry, Dihydrotestosterone- StatPearls Internet. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK557634/
  4. Hughes EC, Saleh D. Telogen Effluvium. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320655/
  5. Popa, A., Carsote, M., Cretoiu, D., Dumitrascu M.C., Nistor, C.E., Sandru F. (2023, Feb). Study of the Thyroid Profile of Patients with Alopecia. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9918246/
  6. Aboud, A., Crane, J. (2023, Aug). Tinea Capitis. StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK536909/
  7. Guo, E., Katta, R. (2017, Jan.) Diet and hair loss: effects of nutrient deficiency and supplement use. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315033/
  8. Saleh, D., Nassereddin, A., Cook, C. (2023, Aug). Anagen Effluvium. StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482293/
  9. AAD. (n.d.) Thyroid disease: A checklist of skin, hair and nail changes. Retrieved from https://www.aad.org/public/diseases/a-z/thyroid-disease-skin-changes
  10. Lee, W.S., Juhasz M., Mobasher P., Ekelem C., Mesinkovska N. (2018). A Systematic Review of Topical Finasteride in the Treatment of Androgenetic Alopecia in Men and Women. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6609098/
  11. Zito, P.M., Bistas, K.G., Syed K. (2022, Aug. 25). Finasteride- StatPearls. NCBI Bookshelf. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK513329/
  12. Badri, T., Nessel, T., Kumar, D. (2023). Minoxidil-StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482378/.
  13. Murugusundram, S. (2009). Serenoa Repens: Does It Have Any Role in the Management of Androgenetic Alopecia? Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2840915/
  14. AAD. (n.d.) Hair loss: Who gets and causes. Retrieved from https://www.aad.org/public/diseases/hair-loss/causes/18-causes
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Knox Beasley, MD

Dr. Knox Beasley is a board certified dermatologist specializing in hair loss. He completed his undergraduate studies at the United States Military Academy at West Point, NY, and subsequently attended medical school at Tulane University School of Medicine in New Orleans, LA. 

Dr. Beasley first began doing telemedicine during his dermatology residency in 2013 with the military, helping to diagnose dermatologic conditions in soldiers all over the world. 

Dr. Beasley is board certified by the American Board of Dermatology, and is a Fellow of the American Academy of Dermatology.

Originally from Nashville, TN, Dr. Beasley currently lives in North Carolina and enjoys spending time outdoors (with sunscreen of course) with his wife and two children in his spare time. 

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