The connection between tamoxifen and hair loss is not well understood. A small percentage of patients who take this drug may experience some thinning of the hair, though it is not certain whether this thinning is caused by tamoxifen or by the conditions the drug is taken to treat. When treatment is no longer needed, a patient can stop taking tamoxifen, and hair loss will generally reverse within a few months or a year.
Healthcare professionals estimate that tamoxifen and hair loss are connected in perhaps 5 percent of patients who take this drug. Of these patients, some may experience total hair loss, while others may see only a slight thinning of the hair. Hair loss is most common with the hair on the head, though hair can fall out or thin on the rest of the body as well.
Hair loss is considered an extremely rare side effect of tamoxifen. In many cases, patients who take tamoxifen may experience hair loss as a result of another condition or treatment they are taking. Tamoxifen may be used to lower the risk of developing breast or other cancer or as part of a treatment plan to fight cancer. When used alongside other treatments, such as radiation or chemotherapy, hair loss is more likely to occur. Though a patient is taking tamoxifen and hair loss is experienced, this does not mean that this particular drug is the cause of a patient's hair loss.
Patients who need to take tamoxifen for a long time and who experience hair loss, whether from the medication or from an another cause, can usually treat the hair loss with over-the-counter medication. In some cases, the hair continues to thin and fall out for the entire time that a patient is taking the medication, which means that the hair loss will need to be treated throughout this time. This side effect is not life-threatening, however, so patients can chose not to treat the hair loss and simply wait out the medication.
Once treatment with tamoxifen is stopped, most patients who experience hair loss see a reversal within a couple of months. Thin hair will usually grow back to the way it was before treatment started, though it is also possible for a patient's hair to grow back thinner or thicker than it was before. In rare cases, patients may experience permanent hair loss, though this is not generally seen as a side effect of tamoxifen.