Does testosterone cause hair loss?

Key Points

• There are many potential causes of hair loss. But the most common is male (or female) pattern baldness—also known as androgenetic alopecia.
• People with male pattern baldness have a genetic difference. Their hair follicles are more sensitive to a hormone (DHT) that causes hair loss.
• Finasteride (Propecia) and Dutasteride are two prescription hair-loss medications that can prevent or slow down age-related hair loss.

Wondering if there’s a link between hair loss and testosterone levels? The short answer is no—testosterone doesn’t cause hair loss. But the long answer is pretty complex.

Some people have a genetic difference that makes their hair follicles more sensitive to a testosterone offshoot called dihydrotestosterone (DHT). DHT plays an important role in puberty in those assigned male at birth (AMAB).

But after puberty? In people with this genetic difference, DHT can wreak havoc on hair follicles and lead to male (or female) pattern hair loss. In this article, we’ll break down exactly how this happens.

And if you’re looking for a solution for your thinning hair, Dr. B offers convenient prescription hair loss medications.

Understanding hair growth

Hair grows on every part of the body except for the lips, palms and soles of the feet. And hair health is about more than just looks.

Hair plays an important role in temperature regulation, touch sensitivity and protection from irritants. Tiny hairs in the nose and ears help filter air and keep out dust. Our eyebrows and eyelashes protect our eyes from debris, too.

Most humans lose around 100 hairs every day. This usually doesn’t cause a problem since the scalp has more than 100,000 hairs overall. The average hair lasts about two to eight years before falling out.

At any given time, about 90% of your hair strands are in their growth phase. The other 10% are in a resting phase. When the resting phase ends, hair loss occurs and a new hair strand grows in its place. But as you age, the growth phase gets shorter and fewer hairs stay in the growth phase, which can contribute to thinning hair.

Androgenetic alopecia—the most common cause of hair loss

It’s normal to lose some hair loss as you get older.

Androgenetic alopecia (AA) affects more than half of men over 50. A genetic condition, it’s also known as male pattern baldness. This type of hair loss usually starts at the temples and forehead (a receding hairline).

Women can also have age-related hair loss. Female pattern baldness affects one in three women over 70. It usually looks like a bald spot on the top of the head (the crown).

There are many other possible causes of hair loss, including:

• Stress or poor sleep
• Infection or illness, including Covid-19
• Rapid weight loss or poor nutrition
• Childbirth
• Hormones
• Medical conditions like alopecia areata
• Certain medications
• Restrictive or tight hairstyles (also known as traction alopecia)

If you notice thinning hair, bald patches or more hair than usual in the shower drain, talk to your medical provider about potential causes and treatment options.

What causes androgenetic alopecia?

Hair loss is a hereditary condition that affects both men and women. If you have a parent with AA, then you’re more likely to experience hair loss as you age.

The condition is often triggered by specific male hormones called androgens.

Dihydrotestosterone (DHT) is a powerful androgen that’s created when testosterone binds to another enzyme. During puberty, it’s responsible for changes like voice lowering and genital maturation.

DHT also binds to hair follicles and causes the follicle to shrink. This is called follicle miniaturization. As the follicle shrinks, it can shorten the growth phase so hair falls out more quickly. Over time, the growth phase gets shorter and shorter, and the hair follicle itself gets smaller and smaller. Small follicles make it impossible for healthy hair to survive.

Peoplewith AA have hair follicles that are more sensitive to DHT. While the average person might have one hair in the resting phase for every 12 hairs that are growing, people with AA may have only five hairs in the growth phase for every one hair in the resting phase.

So, does testosterone cause hair loss?

In short—no. Testosterone alone is not the cause of hair loss.

Instead, people with AA have increased sensitivity to a testosterone byproduct called DHT. When DHT binds to the hair follicle, it can damage the follicle and lead to thinning hair and baldness.

Both those assigned male at birth (AMAB) and assigned female at birth (AFAB) can develop AA. But since AMAB people have higher levels of testosterone after puberty, they are more likely to develop the condition.

So while testosterone does contribute to hair loss, the true culprit is genetics. If you have a family history of male- or female-pattern baldness, you have a greater chance of developing it, too.

How to treat male pattern baldness

It’s important to take good care of your hair. If you notice thinning hair, talk to your provider. You have a better chance of stopping or slowing down hair loss if you catch it early.

You can support healthy hair growth with these tips:

• Eat a well-balanced diet that includes quality protein sources
• Manage stress and get enough sleep
• Avoid hair products with harsh chemicals
• Minimize heat styling
• Use a soft-bristled brush and brush gently
• Avoid wearing tight or restrictive hairstyles or headgear for long periods
• Review your medications with your provider to see if any may contribute to hair loss

There are medications that can help slow down and prevent age-related hair loss. Medications like Finasteride (Propecia) block DHT formation, which can protect the hair follicle. These medications need to be taken long-term. When you stop using them, hair loss will resume.

Other options for treating hair loss include hair transplants and light therapy.

Need a prescription for hair loss medications? Dr. B offers convenient online consultations for men and those assigned male at birth.

You’ll fill out a short health questionnaire to get started, sharing your symptoms and health history. If appropriate, a licensed provider will send a prescription to your pharmacy of choice. We’ll even help you find the lowest prescription cost at your local pharmacies.

Learn more about how it works or get started today!

Sources

Czech, T., et al. (2022). Characteristics of hair loss after Covid-19: A systematic scoping review. Journal of Cosmetic Dermatology.

Ho, C.H., et al. (2022). Androgenetic alopecia. StatPearls Publishing.

Hughes, E.C., et al. (2023). Telogen effluvium. StatPearls Publishing.

Kische, H., et al. (2017). Sex hormones and hair loss in men from the general population of northeastern Germany. JAMA Dermatology.

MedlinePlus. (2022). Alopecia areata.

MedlinePlus. Hair problems.

MedlinePlus. (2023). Hair loss.

Natarelli, N., et al. (2023). Integrative and mechanistic approach to the hair growth cycle and hair loss. Journal of Clinical Medicine.

Phillips, T. G., et al. (2017). Hair loss: common causes and treatment. American Family Physician.

Pulickal, J.K., et al. (2023). Traction alopecia. StatPearls Publishing.