Have there been any links between Mirena IUDs and hair thinning or falling out? I am experiencing this and am certain it’s from Mirena use. Thank you for any information you can provide or point me to.

— Jessie from Canada

[Have a question about women’s health? Ask Dr. Gunter yourself.]

Short Take

Hair thinning can have many causes. It is possible that a Mirena Interuterine System (IUS) may play a role, as hair loss is seen in approximately 0.33 percent of women who use one. However, more information and testing may be indicated before concluding the Mirena or other hormonal IUD has a role.

Tell Me More

Hair goes through phases where it is growing (the anogen phase) and resting (the telogen phase). During the resting phase, hair falls out and the follicle becomes dormant. After a period of time, the hair follicle becomes active again and begins another cycle of growth and rest. It is normal to lose between 50 and 100 hairs a day as part of this cycle.

Sometimes a life event, such as stress, medical conditions, certain medications and, most notably for women, hormonal changes postpartum, can trigger an event called telum effluvatum, basically a mass rest phase. During this time, more hair than normal gets the “go to sleep signal” and women will notice significantly more hair loss than normal. The hair loss can be very dramatic, even affecting more than 50 percent of hair follicles. Medical conditions or events that can trigger this kind of hair loss include iron deficiency, thyroid disorders, extreme diets and even surgery. If you take certain supplements they too could have a role, so that should be considered as well during an evaluation about hair loss.