How much can low ferritin affect how tired you feel?

July 29, 2021 10:30 PM

If I have a low(ish) ferritin level but normal iron, TIBC, and transferrin saturation, could the ferritin level still be causing my fatigue?

For months, I've felt really tired every afternoon and usually have to take a nap for an hour or two. I've also had a lot of trouble getting out of bed in the morning -- I wake up enough to turn off my (multiple) phone alarms and then fall back asleep. (I even have an alarm that I can't turn off until I do several math problems.) Then I end up waking up at 9:00 or 9:30 instead of 7:00 or 8:00 as I intended. I've never these problems to this extent, and it's really affecting my life. (My sleep habits and eating habits haven't changed a ton during the pandemic, I haven't gotten COVID (i.e., long COVID isn't a factor), and I haven't gained weight. I don't think this is related to depression/anxiety.)

When I had a physical earlier this year and told my doctor about being so tired every day, she ordered the normal annual bloodwork plus B12, Vitamin D, and ferritin. My TSH was fine, CBC was fine, B12 was fine, Vit D was 33 ng/mL (low end of normal), and my ferritin was 12 ng/mL (also low end of normal). I take 1000 IU of Vit D daily and also take B12 daily.

My ferritin has never been tested before. If my iron, TIBC, and transferrin saturation were all normal, could my ferritin level make me this tired every day?

More info: I'm a woman and a vegetarian (not vegan).

I will be talking to my doctor, but I'm hoping to hear from other people with low/low-ish ferritin with otherwise normal lab results. I'm just so tired of being tired...

posted by trillian to Health & Fitness (15 answers total)

It sounds like at the very least you should try setting your alarm for 9. You clearly need more sleep right now, regardless of whether that’s temporary or whatever else is going on.
posted by iamkimiam at 11:01 PM on July 29, 2021

Both VitD and ferritin can impact energy.
posted by DarlingBri at 11:53 PM on July 29, 2021

Hell yes, low ferritin (iron stores) can make you tired.dizzy, lethargic, forgetful, brain fog, the whole lot. This was me (a vegetarian woman) and until a new doctor in my early 20s tested my ferritin levels I had so much fatigue I wanted to curl up in a ball and die. I felt so awful and had to drag myself everywhere, and still run out of energy before I did anything. B-12 injections (not pills, or brewers yeast or patches) and later on Iron infusions changed my life. I’d hightail it to a compassionate and doctor who actually listens to you and have them do a compete work up including ferritin levels, which are not normally included in regular bloodwork. Also...if you have any kind of heavy period going on, it would be worth it to get a gyn visit in there too.
posted by Champagne Supernova at 11:58 PM on July 29, 2021

I have many chronic health issues, so diagnosing fatigue can be difficult for me since it comes in waves. However. I had low ferritin a while back. Low vitamin D at one point but not while having that issue. Normal other labs.

I can't supplement orally and there's a chance even if I could I wouldn't absorb it (hence why it was probably low in the first place as I was no longer menstruating). So I got 2 short iron infusions. I was napping sometimes for 4 hours a day. And that improved within months.

Talk with your doctor about supplementing. There are different types. But also explore other options. Also explore why it may have been low (nutrition, menstruation, etc)
posted by Crystalinne at 2:39 AM on July 30, 2021

Yes. In my opinion, the lower limit of normal (11 in most labs) is way too low. It should be at least twice that.
posted by basalganglia at 2:43 AM on July 30, 2021

Oh my god 1,000 times yes. It was really hard for me to convince my GP the cause of my fatigue was low iron (Your numbers are ‘normal!’) Eventually the numbers dropped below ‘normal’, I was able to access transfusions and they turned my fatigue around 100%. The haematologist I saw told me that ‘normal’ and ‘optimal’ are very different and that she likes to see numbers much higher. You might try saying you’d like to see if a transfusion helps just to eliminate low ferretin as a possible cause of your fatigue. If you have an infusion and you’re still exhausted, well, it wasn’t the ferretin.
posted by t0astie at 4:10 AM on July 30, 2021

I asked something similar recently, as I've had ongoing fatigue issues since being diagnosed with anaemia in 2019, except my haemoglobin is now back in the normal range but my ferritin and iron saturation are still on the low end of normal, and I'm still experiencing fatigue even though the doctors I've seen lately have been like "la la la, your haemoglobin is fine, so you're fine! maybe you have ME/CFS or mental health problems, neither of which we can really help with!" (I had a mental health evaluation off the back of this conversation and, as I could have told them without them bothering, they found no compelling psychiatric reason why I'd be experiencing this degree of fatigue).

And I completely agree that the bottom end of the "normal" ferritin range, particularly for women/people perceived as women, is absurdly low - I can't find the link now but I read something while I was deep in compulsive research on this topic which implied that iron deficiency is so common and chronic to so many people that the bottom end of the "normal" range was made artificially low by how low the samples across test populations were in many cases - I also found some papers suggesting that the data that informed those reference ranges wasn't particularly solid and that they haven't really been re-examined for a long time. Garbage reference ranges make for garbage treatment and mean that lots of people who might benefit from treatment never get offered it because they're "fine" according to the reference range.

"Iron deficiency without anaemia" might be a useful search term, I found papers like this one from that search term, although it's significantly harder to find studies and information about iron deficiency without anaemia compared to iron deficiency anaemia. I also found a bunch of medical tables suggesting that ferritin below 30ng/l can be indicative of iron deficiency, with or without anaemia, which would definitely put me in that range too (mine was around 25ng/l last time I got tested). Other papers that might be of interest: Cambridge 2017 (conclusion: treating non-anaemic iron deficiency might help with fatigue), BMJ 2017 (conclusion: treating non-anaemic iron deficiency seems to help with subjective feelings of fatigue but has less of an effect on objective capacity measures).

Unfortunately, the medical profession doesn't seem to have reliably and uniformly caught up with this information, and many doctors are just absurdly wedded to those garbage reference ranges. I'm in the UK, and access to treatment also seems to depend on where you live - I found a clinic in Oxford (where, sadly, I don't live) accepting referrals for iron infusions from anyone with ferritin below 100ng/l (literally 75ng/l higher than mine was at last testing!) or transferrin saturation below 20% (mine was 16% at last testing) regardless of haemoglobin scores - and yet the GP I spoke to last said she couldn't even justify prescribing me more iron tablets, let alone an infusion, based on my haemoglobin being back in the normal range.

Basically, it seems like it's a crapshoot whether anyone will take this seriously and it totally depends on how well-informed your doctor is. It's also galling that I have the capacity to read medical papers on this topic and come to my own conclusions, but nearly every doctor I've ever met has treated me as though I have the mental capacity of a child just because I'm not a doctor and they are. I've basically given up on getting any joy out of the NHS where I live on this topic, and have been trying to make lifestyle modifications to help deal with/improve the fatigue. I've considered getting a private infusion, but that costs around £800 and I can't quite bring myself to spend £800 on something that may or may not actually help with the problem.

Finally, one thing to consider is the overall bizarre & stressful circumstances of the last few years. I've heard of lots of people who've never experienced fatigue before suddenly experiencing pretty intense fatigue in the last year, regardless of their bloodwork and underlying health status. I've been wondering how much my own fatigue is linked to these two low blood scores that I'm fixating on because I like to understand cause and effect and identify solvable problems, and how much of it is just straight-up burnout, an understandable physical reaction from my body after I've spent a year and a half trying to make it perform as normal during extremely abnormal times. It's a much less satisfying, medicalised and treatable explanation, and the part of my brain that just wants to know what is wrong and fix it doesn't like that kind of explanation, but I feel like I can't brush it aside as a possibility.
posted by terretu at 4:25 AM on July 30, 2021

Those numbers are low. I had similar numbers, addressed them, and now I've got more energy.

I started taking a D supplement and then moved to California, where the sun is abundant. I can feel the difference.

I started taking a Floravital supplement and that helped. Right now I'm trying to eat 2-3 cups of lentils/day with some sort of vitamin C to help it actually digest (lemon, tomato, etc), and that seems to be working for me, too.
posted by aniola at 7:24 AM on July 30, 2021

Yes it absolutely could and did for me. I had no success and a lot of stomach issues with vegetarian supplements, but heme iron supplements turned me around over 6 months.
posted by congen at 7:33 AM on July 30, 2021

There has been some re-evaluation on what is fine for TSH levels, decreasing the upper range limit from 5 to 2.5 for many. Something to research if your level was higher than that.
posted by meijusa at 12:24 AM on July 31, 2021

Thank you so much for all the helpful answers (and MeFi Mail)!

I got this message from my doctor through the patient portal after posting this Ask. (She always calls with the results from my bloodwork, but not this time for some reason.)

Blood work looks good except for mildly elevated [unrelated thing]. Please [doctor advice]. [Other unrelated thing] is improved but still minimally high. Can just be observed for now.
Please let me know if you have any other concerns.

So I'll be replying to her about the D and the ferritin...
posted by trillian at 2:17 PM on July 31, 2021

So the doctor's office called and said that my doctor wants me to come in for an appt. today, so at least we'll get to talk about this in person! Fingers crossed she takes me seriously. She's usually great about that.
posted by trillian at 6:56 AM on August 2, 2021

Sometimes when I have low energy, I eat more food with Vit B12, mostly red meat, and it sometimes helps. Supplements exist. I hope the doctor's visit was helpful.
posted by theora55 at 7:39 AM on August 3, 2021

(Continuing to update this in case it helps a future Mefite.)

Well... disappointed with my doctor's appt. She said my (related) bloodwork was all fine and asked if I had shortness of breath at all or if I snore (no, and no) and also asked screening Qs for anxiety/depression. She listened to my lungs and the nurse took my vitals, and that's about it. I asked her about the barely-normal D and ferritin levels (and said I already take 1,000 IU of D daily) and she said it's not why I'm tired -- that they're fine. She also said, "You can take iron if you want." She also said I could get a sleep study done but it would take three months to get one scheduled. Paraphrasing, the message was basically, "Otherwise, I don't know why you're tired."

I called my ob/gyn's office to see if I could get a second opinion, so I'm having the bloodwork sent over.
posted by trillian at 3:49 PM on August 5, 2021

So my ob/gyn replied to my online portal message to say that all my bloodwork looked fine, concluding, "I can't think of anything else except perhaps Lyme testing (which is imperfect) that could be tested for that wasn't already done." Sigh.

If anything helpful develops, I'll post another update for future searching Mefites...
posted by trillian at 5:51 AM on August 19, 2021