Letrozole is an oral medication primarily used to treat hormone-receptor-positive breast cancer in postmenopausal women. It influences the body’s hormonal balance. Often prescribed long-term, sometimes for five years or more, it helps prevent cancer recurrence or manage advanced disease.
Is Hair Loss a Side Effect?
Hair thinning is a potential side effect of letrozole. Clinical studies report hair loss or thinning (alopecia) in approximately 3.4% to 6.2% of women using the medication. While complete hair loss is uncommon, broader surveys suggest rates as high as 20% to 30% for aromatase inhibitors generally. The experience of hair thinning can vary significantly among individuals.
This hair thinning is typically mild to moderate. Most reported instances were not classified as severe, and it is generally milder compared to hair loss often associated with chemotherapy.
How Letrozole Affects Hair Growth
Letrozole is a non-steroidal aromatase inhibitor. It blocks the enzyme aromatase, which converts androgens into estrogens in the body. Since certain breast cancers are stimulated by estrogen, reducing the body’s estrogen levels helps slow or stop the growth of these cancer cells.
Estrogen helps maintain healthy hair follicles and extends the hair’s growth (anagen) phase. When letrozole reduces estrogen, this protective effect diminishes. Decreased estrogen can cause more hair follicles to prematurely enter the resting (telogen) phase, resulting in diffuse hair thinning rather than localized baldness.
Strategies for Managing Hair Thinning
Managing hair thinning with letrozole involves gentle care and professional consultation. A gentle hair care routine minimizes stress on existing hair. This includes avoiding harsh chemical treatments, excessive heat styling, and tight hairstyles. Using mild shampoos and conditioners, and patting hair dry, can also reduce damage.
Nutritional support is also considered. Supplementing the diet with hair-supporting vitamins and minerals, such as Vitamin C and Omega-3 fatty acids, may be beneficial. Topical treatments like minoxidil, an FDA-approved hair growth medication, can be discussed with a healthcare provider. Consulting an oncologist or dermatologist is important to determine suitable strategies and rule out other causes of hair loss.
Other Common Letrozole Side Effects
Beyond hair thinning, letrozole can cause other side effects, many related to reduced estrogen levels. Common side effects include hot flashes and joint pain (aromatase-inhibitor associated arthralgia). Over a quarter of individuals in clinical trials reported joint pain, and about 10% experienced muscle pain.
Other reported side effects include fatigue, headaches, dizziness, increased cholesterol levels, swelling in extremities, or mood changes. Discuss any concerns or bothersome side effects with your healthcare provider.