Iodine is one of my favorite supplements for women’s health (just behind magnesium and zinc).
I prescribe iodine for breast pain, ovarian cysts, ovulation pain, and PMS, and I prescribe it even when there is no thyroid problem. In fact, I am more cautious with iodine when there is a thyroid problem because iodine can be dangerous for the thyroid.
Benefits beyond thyroid
Iodine is required for the health of many parts of the body, including the brain, immune system, prostate gland, ovaries, uterus, and breasts. In fact, more than 70 percent of the body’s iodine is concentrated in those tissues—and not in the thyroid. Iodine is in those tissues because it plays a key role in immune function, detoxification, and mitochondrial regulation.
Iodine also affects ovulation and estrogen.
Iodine promotes ovulation
There’s more iodine in the ovaries than any other organ except the thyroid. Sufficient iodine promotes healthy ovulation. It also reduces ovulation pain, prevents ovarian cysts, and boosts progesterone (because ovulation is how you make progesterone). Read Road Map to Progesterone.
If you suffer any of these conditions, then you likely need a small dose of iodine. That is true even if you have autoimmune thyroid disease (Hashimoto’s). I don’t agree that thyroid disease means you must avoid all iodine. But if you have Hashimoto’s, you need to stay low with the dose. See below and talk to your doctor.
👉 Tip: The term “ovarian cyst” refers to abnormally large cysts or functional cysts. It does not refer to the multiple small follicles of polycystic ovary syndrome becuse those are not cysts. Read Maybe It’s Not PCOS.
Best forms of iodine
There are three main forms of supplementation: potassium iodide (KI), molecular iodine (I2), and seaweed which contains a mix of KI, I2, and iodate (IO3-).
There is no topic in natural medicine more controversial than the dosing of iodine.
On the one hand, conventional medicine is very conservative. The RDA is 150 mcg (0.15 mg) with an upper tolerable limit of 1,100 mcg (1.1 mg). Thyroid experts argue that doses greater than 500 mcg (0.5 mg) can trigger autoimmune thyroid disease, and doses greater than 225 mcg (0.25 mg) are not safe for pregnant women.
On the other hand, practitioners like David Brownstein advocate for mega-doses up to 50,000 mcg (50 mg) per day. That is 100 times (10,000 percent) greater than what your doctor considers safe.
I usually prescribe in the 300 – 3000 mcg (0.3 – 3 mg) range, but only after first testing for thyroid autoimmunity (see below).
Random “urinary iodine” is the most common test. It’s not a perfect test and is primarily recommended for population studies, not individual assessment. Read Controversies in urinary iodine determinations. Deficiency is defined as less than 100 mcg/L (after adjustment for creatinine). To make the test more reliable, I ask my patients to test in the morning and to avoid iodine-containing supplements, foods, or thyroid medication for 24 hours prior.
A 24-hour urine test is more accurate, but is still not perfect and is a chore to do.
There is something called an iodine challenge test but I don’t trust its accuracy. Also, it involves giving a single dose of 50,000 mcg (50 mg) to a patient, which is arguably not safe (especially for anyone with autoimmune thyroid disease).
Thyroid antibodies (thyroid autoantibodies, anti-thyroid antibodies, anti-TPO antibodies) is the single most important test to do before supplementing. It is a marker of underlying autoimmune thyroid disease and can predict if supplementation is likely to trigger full-blown thyroid disease (Hashimoto’s). You can still take some iodine with autoimmune thyroid disease (remember, you need it for your breasts and ovaries!), but you probably want to stay at a low dose like 250 mcg (0.25 mg).
Breast tenderness is a reliable symptom of deficiency. I find it more useful than any test.