What is Hypothalamic Amenorrhea?
By Kelsey Chadwick, MS RDN
May 23rd 2025
Hypothalamic amenorrhea is a term you might hear a lot during eating disorder recovery. Let’s break it down: “amenorrhea” means the absence of a period, and “hypothalamic” refers to the hypothalamus — basically the brain’s control center. This part of the brain manages a bunch of important functions like body temperature, thirst, sleep, hunger, sex drive, and mood. It also plays a big role in reproduction by producing hormones that help regulate your menstrual cycle.
There are two types of amenorrhea:
Primary amenorrhea is when someone hasn’t started their period by age 16 or within five years of starting puberty.
Secondary amenorrhea is when someone who used to have regular periods stops getting them for more than three months.
When your body is under stress — whether from not eating enough, intense exercise, poor nutrition, or emotional strain — the hypothalamus can go into “survival mode.” This means it may shut down less essential functions, like menstruation, to focus on keeping you alive. That’s one reason people with eating disorders often stop getting their period.
According to the American Society of Reproductive Medicine, hypothalamic amenorrhea affects about 17.4 million women worldwide — including around 1.62 million women aged 18–44 in the U.S.
One hormone that plays a major role here is estrogen. Estrogen is one of the primary female sex hormones and is essential for a healthy menstrual cycle. But it also helps keep bones strong by supporting calcium absorption. When estrogen levels drop too low — as they often do in hypothalamic amenorrhea — bone health can suffer, increasing the risk of fractures or osteoporosis.
Some people think that going on birth control can “kick-start” their period again, but unfortunately, that’s not true. Oral contraceptives don’t actually fix the underlying issue or protect your bones. As Dr. Jennifer Gaudiani puts it in her book, taking the pill in this context is basically just “giving someone a hormone-induced monthly blood loss.”
It’s really important to work with your treatment team — including a doctor and a registered dietitian — to address the root causes of hypothalamic amenorrhea and monitor your bone health along the way.
Another common misconception is confusing hypothalamic amenorrhea with polycystic ovary syndrome (PCOS). While both involve hormone imbalances and can affect menstruation, they’re very different. PCOS is a condition where the ovaries produce too many androgens (a type of hormone usually linked with male traits), which throws off your reproductive hormones in a different way.
It’s also important to remember that menstrual health doesn’t always line up with body size. Some people with a “normal” BMI might lose their period, while others who are underweight might still get theirs. Genetics can play a big role here, so it’s not always predictable.
To diagnose hypothalamic amenorrhea, your healthcare provider will first rule out other possible causes for missed periods, like thyroid or adrenal issues. They’ll likely do a physical and pelvic exam, and run blood tests to check hormone levels like estrogen, prolactin, FSH (follicle-stimulating hormone), and LH (luteinizing hormone).
As for treatment? Getting support for your eating disorder is absolutely key. Recovery — including proper nutrition and weight restoration — is an essential step toward restoring your period and protecting your long-term health. Working with your healthcare team, including a registered dietitian, to formulate a nutrition recovery plan is essential.
Sources
Pettersson F, Fries H and Nillius SJ. Epidemiology of secondary amenorrhea: I. Incidence and prevalence rates. American journal of obstetrics and gynecology. 1973;117:80–86.
Gaudiani, Jennifer L. Sick Enough: A Guide to the Medical Complications of Eating Disorders. Routledge, 2019.