Your Exhaustion Might Not Just Be Your Endometriosis
Clinically reviewed by Dr. Alessia Milano, ND, a licensed naturopathic doctor registered with the College of Naturopaths of Ontario (Reg. #3697). Last reviewed October 2026.
Fatigue is one of the most common complaints among people with endometriosis, and it often gets brushed off as just part of the condition. Chronic pain wears you down. Inflammation drains your energy. Poor sleep from cramping adds up. All of that is real.
But there is another cause that gets missed surprisingly often: low iron.
Why endometriosis and iron deficiency often show up together
There are two main reasons.
1. Blood loss.
Many people with endometriosis have heavy or prolonged periods. Some also have conditions that travel alongside it, like adenomyosis or fibroids, which can make bleeding heavier. Every period means losing blood, and blood carries iron. When you lose more iron each month than food can replace, your stores slowly drain. Because this happens over months or years, the drop is gradual and easy to miss. You adjust to feeling worse without realizing it.
Signs your bleeding may be heavy enough to lower your iron: soaking through a pad or tampon every hour or two, periods lasting longer than seven days, or passing large clots. Any of these is worth raising with your doctor on its own.
2. Inflammation.
Endometriosis is an inflammatory condition. Inflammation itself can reduce iron absorption and the way it’s processed in the body. In studies of people with endometriosis, about half were iron-deficient, and many of them did not have heavy bleeding.
Signs your tiredness might be about iron
Iron deficiency can look a lot like the general fatigue of endometriosis, which is part of why it hides so well. Some signs to watch for:
Exhaustion that does not improve with rest
Getting out of breath on stairs or short walks
A racing or pounding heartbeat
Headaches or dizziness
Brain fog or trouble focusing
Hair shedding more than usual
Cold hands and feet
Restless legs, especially at night
Brittle nails
Why one blood test may not be enough
The usual first test for iron is ferritin, which measures your iron stores. It is a good start, but because of the inflammation that shows up with endometriosis, ferritin can look falsely normal even when your iron is actually low.
For this reason, ask whether your workup can also include a complete blood count and a full iron panel, including transferrin saturation (TSAT). Transferrin saturation shows how much iron is actually available for your body to use, and it can reveal a deficiency that ferritin alone would miss.
What treatment can look like
Replace the iron. Treatment usually begins with iron supplements or increasing iron-rich foods. Pairing iron with vitamin C (such as citrus) can help absorption, while coffee and tea around the same time can reduce it.
Consider an IV option. If tablets upset your stomach, do not raise your iron enough, or if ongoing bleeding and inflammation are getting in the way, iron given through an IV may work better and faster.
Treat the source. If heavy bleeding is draining your iron, the bleeding itself also needs attention. Options to manage heavy periods or endometriosis can help stop the cycle rather than just topping up iron over and over.
You deserve answers, not just "that's normal for you".
People with endometriosis are often told their symptoms are simply part of the disease. Sometimes that is true. But sometimes there is something else going on, and it is treatable.
If you have been dragging yourself through each day and assuming that is just how it has to be, ask about your iron. A few simple blood tests could make a real difference in how you feel.
Ready to make a change?
Book a complimentary 15-minute consultation to learn how naturopathic care can support you in better understanding your symptoms and exploring your next steps.
Be well,
Dr. Jessica Nazareth , ND
Frequently Asked Questions About Endometriosis and Iron Deficiency
Can endometriosis cause iron deficiency?
Endometriosis can be associated with iron deficiency, particularly when heavy or prolonged menstrual bleeding occurs. Inflammation may also affect how the body processes iron. However, not everyone with endometriosis has low iron, which is why appropriate testing is important.
Can I have low iron even if my periods aren't heavy??
Yes. Research has found that iron deficiency can occur in people with endometriosis even without heavy menstrual bleeding. This means that normal or lighter periods don't necessarily rule out low iron, particularly if you're experiencing persistent fatigue or other symptoms.
What are the signs of iron deficiency with endometriosis?
Common symptoms include ongoing exhaustion, dizziness, headaches, brain fog, shortness of breath during physical activity, heart palpitations, and increased hair shedding. Because these symptoms can overlap with endometriosis-related fatigue, bloodwork can help identify whether iron deficiency is contributing.
Can ferritin levels be normal even if my iron is low?
Yes. Ferritin measures stored iron, but inflammation can sometimes increase ferritin levels and make iron deficiency harder to identify. Depending on your symptoms and medical history, your healthcare provider may recommend additional testing, such as transferrin saturation (TSAT).
What blood tests can help identify iron deficiency?
A complete blood count (CBC) and ferritin are common starting points. In certain situations, additional iron studies, including transferrin saturation, may help provide a clearer picture. Your healthcare provider can determine which tests are appropriate based on your symptoms and medical history.
What treatment options are available for iron deficiency?
Treatment typically involves oral iron supplementation and addressing the underlying cause of iron loss. IV iron may be considered when oral supplements aren't tolerated, aren't effective, or aren't adequately absorbed. Managing heavy menstrual bleeding and other contributing factors is also important for preventing iron deficiency from recurring.