My doc says my Free T3 is a bit low but it's nothing to worry about.
I also have anemia, at 12.3. Again, she says not to worry much about it... probably because she sensed I'm a bit stressful and anxious/depressed, some conditions I've googled that are associated with a low free t3.
P.S.: I lost a lot of weight in the past several months.
EDIT: Saw something online:
Generally a low free T3 is associated with hypothyroidism. In most of the cases the very first sign of a disease related to the thyroid is indicated by the TSH abnormal levels.
However, many of the patients experience the symptoms of this type of disease even if the test results come with a normal TSH. Hypothyroidism is taken into consideration even if TSH levels are normal but T3 is lower. Thus, normal TSH low T3 can still indicated a thyroid related problem. Low TSH and high T4 and T3 suggest hyperthyroidism.
Low T3 levels are almost always linked to thyroid related illnesses, mostly hypothyroidism, conditions that are manageable and treatable with specific medication, under the endocrinologists’ observation.
If I lost weight though, it shouldn't be hypothiroid...
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You might consider supplementing with selenium, as a deficiency of which leads to a poor conversion of t4 to t3.
I have the same issue. Low T3 (slightly below range), normal TSH, normal T4. Endocrinologist said I was fine and there is nothing to worry about. I'm not so sure, but maybe she is right.
I have heard that low-carb can prevent efficient conversion from T4 to T3. I don't have time at the moment to dig something up, but it's out there.
What you're experiencing is indicative of Hashimoto's which is an autoimmune disease (as Jon mentioned). There is a ton of information online about it, but in a nutshell, there are elevated levels of antibodies (white blood cells) that "kill" the proteins in your thyroid. This is what leads to Hypothyroidism. What can also happen is that the thyroid can "sputter" back to life and go into HYPERthyroidism which may have been why the dramatic weight loss happened before. Definitely talk to your doctor about getting your antibodies/white blood cell count checked. Good luck.
If your T4 is normal and your T3 is low, this is indicative of the liver not converting T4 into T3. T4 is produced by the thyroid and TSH is produced by the brain.
As far as your weight loss, sometimes people can go from being hyperthyroid to hypothyroid with an autoimmunity condition.
My hair was shedding for 3 months and the tricologist after giving me a blood test said my FreeT3 was low. I was on medication 10 mcgs per day and it stopped. My GP has now taken me off the medication and I feel very depressed and have muscle pain. Should I carry on with the medication as I have had another blood test 2 months after I started and it has risen to normal.
If your eating VLC, T3 may fall as your body conserves glucose.
I'm hypothyroid and my T3 was low doing about 30gms carbs a day and I felt like crap. I upped starch to about 80 gms per day and T3 normalized and I feel much better. Still relatively LC but not VLC. I didn't gain any weight either.
My thyroid was a little off last year and I was told it was no big deal. My doctor did refer me to a endocrinologist and then they found I have Graves disease. Feeling a lot better since I've been on treatment. I suggest asking for a referral out to one also... can't hurt. As for the iron, again... go see a specialist. If they can't figure out where it is coming from then they need to send you to someone who can especially if your feeling really tired and losing weight. Something is not right, your body is telling you that loud and clear. Listen to it!
If you're having problem absorbing minerals - like iron, you need to be tested for celiac or gluten intolerance. If you have either of these you can't absorb minerals well, and without minerals your thyroid can't work.
Actually, severe dieting will lower your T3, and worse convert some of your T4 into rT3. This is your body's way of making sure you don't starve - lower the metabolism. When you are already on thyroid meds, some smart doctors will increase T3 (Cytomel) during severe dieting. I'm not sure how and when the body corrects the balance, if simply raising calories is enough?