Serum Iodine low, is this a clue?


Senior Member
I wanted to give a different perspective of the thyroid. I've had TSH, T4, T3, RT3, Free T3, T3 Uptake, Free T4, and Thyroid antibodies done. My free t3 is a "little" low but in the middle of the range. I clearly have some degree of HPA-axis dysfunction, yet there it is clear my thyroid is under performing, regardless.

Test Low Normal High Reference Range Units
Iodine, Serum Or Plasma 40.6 40.0-92.0 ug/L

While 40.6 is "normal," we know what normal really means when it's at the very bottom of the range. Although, I'm not sure if serum iodine is the "gold standard" for iodine testing.

I've been eating 10 eggs a day, and taking a multivitamin with 150 mcg of iodine in it. Yet, my levels are still low. Theoretically, I'm taking in 500-600 mcg of iodine a day. Now, I know there are two schools of thought when it comes to iodine; 1. taking allot of iodine is good, 2. taking allot of iodine is bad. I realize this is a simplistic perspective, and excess iodine can cause hypothyroidism.

Another thing I have come across is that selenium is sort of like a rate limiting factor for iodine intake. It is protective of the thyroid gland, and has been shown to reverse hypothyroidism and hashimoto's.

“A survey of the literature suggests that Hashimoto’s is largely unaffected by iodine intake. However, the literature may be distorted by three circumstances under which iodine increases may harm, and iodine restriction help Hashimoto’s patients:

1. Selenium deficiency causes an intolerance of high iodine.

2. Iodine intake via seaweed is accompanied by thyrotoxic metals and halides.

3. Sudden increases in iodine can induce a reactive hypothyroidism.

All three of these negatives can be avoided by supplementing selenium along with iodine, using potassium iodide rather than seaweed as the source of iodine, and increasing iodine intake gradually.” endquote Renato Iwakura.

It seems like the safest approach with iodine is to start low, 150 mcg in the form of potassium iodide/iodine, along with 200 mcg of selenium, and then gradually increase iodine until you can feel your body temperature increasing and hypo symptoms going away. I'm starting to feel the warmth again slowly, although I'm still fluctuating. Selenium should be 200-400 mcg, but not above 400 mcg. Iodine is more variable but it looks like 1000 mcg should be as high as one should go.
New Mexico
There are a couple books to read. 1) The Iodine Crisis: What You Don't Know About Iodine Can Wreck Your Life by Lynne Farrow. 2) Iodine: Why You Need It, Why You Can't Live Without It by David Brownstein.

They recommend the 24 hour loading test. You take a 50 mg (that is 50,000 mcg) pill of roughly half iodine and half iodide and then collect your urine for 24 hours. Then they measure how much iodine you peed out. If you are deficient then you won't pee out much but if your body is "full" then you should pee out 50 mg. Read the books to learn more about the test.