Is *This* Why You’re So Tired?
How often are you not just tired but brain-dead, bone-weary, please-don’t-ask-me-to-move exhausted? Except your doctor says everything looks good because your thyroid, hemoglobin, blood pressure, and cholesterol tests all come back normal?
That kind of tired is not normal, says Angela Weyand, MD, a pediatric hematologist and associate professor at the University of Michigan. One of Weyand’s clinical interests is in iron deficiency, the symptoms of which include extreme fatigue, weakness, headache, lightheadedness, cold hands and feet, and “unusual cravings,” among others.
Sound familiar? You have lots of company. In July 2023, Weyand and her team released a study that found the overall prevalence of iron deficiency was about 40 percent in young menstruating individuals.
“Iron is the most common nutrient deficiency in the world, but it does tend to affect menstruating people more frequently,” says Weyand. Men, for the most part, take in and hold on to enough iron, but if you’re bleeding monthly, that’s one route to iron deficiency. Recent shifts in women’s reproductive timelines play a role, too. “We have earlier [onset of periods],” says Weyand, “a later age of menopause, and fewer pregnancies, so individuals are spending a greater proportion of their lives losing blood than before.”
That’s a problem because iron is a critical element in the production of red blood cells, and extreme iron deficiency presents as anemia. People are most at risk for iron deficiency and iron deficiency anemia during growth stages, like early childhood, adolescence, and pregnancy.
But Weyand has seen many teen and adult patients struggle mightily with symptoms their referring physician hadn’t realized were probably due to a less extreme iron deficiency. That’s partly because the symptoms are non-specific and could signal other issues. It’s also due to how physicians typically screen for iron deficiency: Historically, a hemoglobin test is ordered, which does not measure iron but does tell you if someone is anemic. Iron deficiency is just one of many possible causes of anemia, and even though it’s the most common cause, many patients with iron deficiency are missed by focusing on hemoglobin alone.
Also, more recent research suggests that one’s ferritin level might be a better indicator (ferritin shows how much iron is stored in the body). Problem is, there’s no consensus around what “normal” is. The World Health Organization sets its healthy range from 15 to 150 μg/l. But the lower limit varies significantly between labs and institutions and, in some instances, drops into the single digits. Weyand also notes that these intervals are based on the levels of “healthy” women volunteers. But a lot of these “healthy” women are iron-deficient themselves.
This frustration is one reason Weyand has become an advocate for getting people tested. (Check her out on X, formerly Twitter, @acweyand.) She is also working to change the diagnostic standard for iron deficiency, in large part because the condition doesn’t just cause crazy exhaustion.
There’s data on iron deficiency and restless leg syndrome, a condition women are more prone to, says Weyand. “Also, a lot of people are [now] talking about iron in your brain, because it’s a known factor for making things like serotonin and dopamine, which are involved with mood. I am not saying that everyone who has depression just needs iron, but there is probably a subset of patients that, if we corrected their iron, wouldn’t even need other things.”
Another aspect concerns menopausal women: Conventional wisdom suggests that they don’t lose iron, because they no longer have periods. But as Weyand points out, if their ferritin levels have been at 11 or 12 or 15 μg/l their whole lives and remain so, then they’re still going to be walking around wrung-out, freezing, lightheaded, and possibly drawn to chewing ice—one of those unusual cravings (some people crave chalk and even dirt) and a potential sign of iron deficiency.
Technically, these women are normal—and in menopause, physicians would likely be more concerned if patients had too much iron (because an excess is toxic) or internal bleeding (low iron levels can be a sign of colon cancer). “Don’t get me wrong,” says Weyand. “People need screening for colon cancer.” But for those who’ve had these symptoms, it might be worth having a conversation with your doctor and testing your ferritin levels, something Weyand says is not often done.
The situation is changing, however: In 2023, the International Federation of Gynecology and Obstetrics announced that women should be regularly tested for iron deficiency throughout their lives. There is also ongoing research to change the recommended minimum levels of ferritin, which would encourage treatment. That will take time, as some patients say they feel fine at 15 μg/l and others are a train wreck unless it’s over 50 μg/l.
Still, the good news is that iron deficiency is treatable: Doctors may recommend an over-the-counter iron supplement. (For patients who experience gastrointestinal issues like constipation or diarrhea, a common side effect of oral iron, they may suggest a prescription that takes that into account.) Weyand also prescribes iron via IV, which can wipe out a deficit, in some individuals and using certain formulations, in one fell swoop. She says this is the best route if doctors have identified and addressed the underlying issue, whether that’s heavy periods, a missing element in diet, or other issue (otherwise the deficiency will recur).
Another reason it’s important to talk to your doctor before taking supplements: In the U.S., about one in 300 non-Hispanic white people are carriers of a rogue gene that causes a condition called hereditary hemochromatosis, a.k.a. iron overload disorder. The rates are lower in other races and ethnicities. Some of the symptoms can be similar to someone suffering from low iron, but the long-term health consequences are serious. A blood test will determine if you’re one of the more than one million Americans affected.
Weyand sees a lot of adolescent patients who thought their exhaustion was due to high-pressure high school—they had no idea they didn’t need to be that tired. She’s also heard from adults on social media who message her saying, “It’s weird that I go into the doctor and say, ‘Well, I follow this hematologist on Twitter…’” But when they get the treatment they need, they DM back: “I feel like a new person!”
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