For some people, unwanted facial hair may affect self-esteem and cause embarrassment. Although facial hair growth isn’t a common side effect of tamoxifen (sold under the brand name Soltamox), some MyBCTeam members have noticed this side effect. One member asked, “Is anyone experiencing increased growth of facial hair since taking tamoxifen?”

Continue reading to learn more about how tamoxifen may cause increased facial hair growth.

How Does Tamoxifen Work?

Tamoxifen is a hormonal therapy used to treat or prevent breast cancer in people with hormone receptor-positive breast cancer. Tamoxifen is a selective estrogen receptor modulator — it binds to estrogen receptors and blocks estrogen from signaling cancer cells to grow and divide. In this way, tamoxifen can slow or stop cancer cell growth.

Tamoxifen can have different effects in different parts of the body. In breast tissue, tamoxifen blocks estrogen. However, in other parts of the body, such as the uterus and bones, tamoxifen can act like this hormone.

Tamoxifen Side Effects

You won’t find excess hair growth in the list of side effects of tamoxifen. In fact, 1 percent to 10 percent of people taking tamoxifen experience the opposite side effect — hair loss or hair thinning. Other common side effects of tamoxifen include:

• Hot flashes (also called hot flushes)
• Sweating
• Edema (swelling) in your hands and feet
• Tiredness and weakness
• Vaginal discharge or dryness
• Rash
• Depression
• Joint pain

Serious side effects include uterine changes, blood clots, and liver problems. You should talk to your doctor right away if you notice any of the following symptoms:

• Vaginal bleeding
• Shortness of breath
• Vision changes
• Chest pain
• Confusion
• Yellowish-looking skin or eyes

What Causes Excess Facial Hair Growth?

Excess hair growth — also called hirsutism — affects up to 40 percent of women and people assigned female at birth, according to Cleveland Clinic. Hirsutism can cause longer, thicker, darker hairs to grow in areas that they normally wouldn’t, such as the face, chest, back, or abdomen.

Hirsutism usually occurs with higher-than-normal levels of androgens, a group of sex hormones that affect puberty and physical maturity. Although people of all genders make androgens, males usually make more than females, according to Cleveland Clinic. For females, an extra high level of androgen hormones can prompt growth in the hair follicles on the face.

Several possible factors can lead to unwanted facial hair growth, but sometimes the cause is unknown.

Medical Conditions

Medical conditions that cause high levels of androgen hormones, such as polycystic ovarian syndrome or androgen-secreting tumors, are known to cause hirsutism.

Other medical conditions that can sometimes cause hirsutism include:

• Thyroid problems
• Cushing syndrome
• Hormone imbalance

Menopause

Hirsutism can occur after menopause, when the ovaries stop making as much estrogen as they normally would. Lower estrogen levels can disrupt the balance of hormones in your body. If your androgen hormone levels don’t fall, your body may react the same as if they were too high. This is known as relative hyperandrogenism.

Breast cancer treatment can cause menopause to start early. Along with hormonal treatments like tamoxifen, chemotherapy may have side effects similar to symptoms of menopause. People who were undergoing hormone replacement therapy (HRT) before being diagnosed with breast cancer must stop HRT, which may also lead to menopause symptoms.

Medications

Many medications can also cause excess hair growth. These include:

• Clomiphene (Clomid)
• Cyclosporine (Neoral, Gengraf, Sandimmune)
• Danazol (Danocrine)
• Medroxyprogesterone (Provera)
• Phenytoin (Dilantin)
• Prednisone (Deltasone)

How Does Tamoxifen Cause Facial Hair Growth?

Taking tamoxifen can lead to excess facial hair growth because of the effects on estrogen. By blocking estrogen receptors, tamoxifen could cause relative hyperandrogenism in a similar way to menopause.

Facial hair caused by tamoxifen isn’t commonly reported in medical journals. One case report in the Journal of Drugs in Dermatology described a woman who began growing unwanted hair on her face, arms, and shoulders in the first eight weeks after starting tamoxifen. The unwanted hair improved after tamoxifen was stopped.

Tips for Managing Facial Hair Growth

Tamoxifen can help reduce your risk of breast cancer by up to 50 percent. It’s important to find ways to manage bothersome side effects so you can continue to get the benefit of taking tamoxifen. As one MyBCTeam member shared, “I wouldn’t stop the tamoxifen for the little side effects. The pros definitely outweigh the cons for me.”

If you notice unwanted facial hair growth, it’s important to discuss treatment options with your cancer care team. The hair growth could be a sign of another underlying condition. Your doctor may refer you to a dermatologist, who specializes in treating skin, hair, and nail conditions.

Weight Loss

If you’re overweight, losing weight may help lower the androgen levels in your body. This might in turn improve unwanted facial hair growth.

At-Home Hair Removal

Home treatments for hair removal include the following:

• Shaving — Using a razor to cut the hair at the surface of the skin
• Waxing — Applying wax and then quickly removing it to pull hairs out of the skin
• Chemical depilatories (such as Nair) — Dissolving the hair with a cream or lotion
• Threading — Pulling out hair using two twisted threads
• Prescription creams — Preventing hair growth with the active ingredient eflornithine (Vaniqa, Eflora)

You should seek medical advice before using any at-home treatments for hair removal. Some of these approaches can damage the skin, which may be risky for breast cancer survivors who have an increased risk of infection. Examples of damage may include cutting yourself while shaving or skin irritation caused by waxing or creams. Additionally, people who take tamoxifen can experience skin changes such as dryness and rashes, which can increase the risk of injury.

MyBCTeam members have used some at-home hair removal methods. One shared, “I have been plucking using tweezers, but it’s never-ending and getting worse.”

“My facial hair has gotten worse on tamoxifen, too,” another member said. “I have to get it waxed. Yes, it may hurt, but I got used to it.”

In-Office Treatments

A more permanent form of hair removal is available at a dermatologist’s office. Hair follicles can be destroyed with procedures such as laser hair removal (using a beam of light) and electrolysis (using an electric current).

Not everyone is a good candidate for these treatments. You should discuss the options with a board-certified dermatologist to see which might be right for you.

MyBCTeam members have had success with laser hair removal. One member shared, “I opted to have laser hair removal. It was good on the hairs that worked, but it doesn’t work on gray hairs!!! Tragic.”

Another member shared, “I have continued with laser hair removal and can say I’m really pleased with the results.”

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 64,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you experienced facial hair growth while taking tamoxifen? What strategies have you tried to help manage unwanted hair growth? Share your experiences in the comments below, or start a conversation by posting on your Activities page.