Iodine is a trace mineral which is primarily used for thyroid hormone production and is necessary for appropriate development and growth.
Our body contains between 20 to 30 milligrams of iodine. Of this, about three-quarters is in the thyroid. This is because iodine makes up the thyroid hormones. T4 and T3 are named as such because of the tyrosine amino acid, and then four or three iodine molecules. The rest of the iodine is scattered throughout the body as every single cell uses it.
Iodine has been called “the thermostat of the human body” and is well regarded for its effects on the metabolism through the action of the thyroid.
What it Does and its Benefits
- Critical for normal growth and development
- Necessary for mental development
- Assists all hormone production
- Needed for use of dietary cholesterol
- Maintains optimal energy levels
- Helps your teeth, nails and hair stay healthy
- Anticarcinogenic properties
- Enhances immune function
- Necessary for proper thyroid function
- Supports metabolism
Signs and Symptoms of Deficiency
Goiter is the classical deficiency disease of a lack of iodine. This shows an enlarged thyroid gland, swelling the neck, as it works to compensate for the lack of hormone production.
Other symptoms that can occur with or without goiter include weight gain, fatigue, constipation, brittle hair, anemia, depression and frustration. A low body temperature may also indicate deficiency.
While deficiency causing goiter is rare, sub-clinical deficiency of iodine is widespread. According to Dr. David Brownstein, probably the foremost expert on the topic, 96% of people are actually deficient in this mineral.
Iodine deficiency may also be a contributing factor to ADHD and reproductive cysts and fibroids. Some doctors have found these can be reversed with regular iodine supplementation.

Hypothyroidism can be caused by a lack of iodine, though that isn’t always the case. If insufficient iodine isn’t had the body can’t make T4 which is the starting place of the thyroid hormones. However, many hypothyroid people have sufficient T4, they just have trouble converting it to the more bioactive T3. If you have blood test numbers you may be able to see if iodine will help you or not, but if you don’t then I would say it’s at least worth experimenting with.
Signs of Excess
Too much iodine can result in hyperthyroidism. Exactly what is too much seems to vary greatly among different people.
It is cautioned that anyone with Hashimoto’s diseases, or autoimmune thyroiditis, should avoid iodine supplementation because it can cause worsen problems. However, there is some evidence that there may still be iodine deficiency in hyperthyroidism, it just needs to be used in combination with co-factors like selenium. It’s possible that just taking iodine alone, without all the necessary co-factors, could exacerbate symptoms.
Some other symptoms of too much iodine include rash, headache, difficulty breathing and a metallic taste in your mouth.
It can also cause what is known as “iodide goiter”. Like a homeopathic proving, too much can cause similar symptoms to what lack of it causes. This was noted in people in Japan eating copious amounts of seaweeds.
Causes of Deficiency
Depending on where you live, the food may have more or less iodine as soil variations differ significantly. The Midwest of the US is poor in iodine, and earned the nickname of the “Goiter belt”. Many mountainous regions throughout the world also have low amounts of iodine in the soil.
Probably the biggest part of the problem, in why so many people are sub-clinically deficient, is that the iodine receptors in the body will take up other halogens in its place, including bromine, chlorine, fluorine, radioactive iodine, and the –ide variations of these. These halogens are fairly widespread in tap water, baked goods, vegetable oils and more. Basically most of our processed food supply.
If there has been a lot of exposure to these things then it can take some time and regular supplementation of iodine to put the iodine back in the cells where it is needed, forcing these halogens out.
And if your hormones and cells are using these other toxic minerals instead, they will not function optimally. Note that the reproductive organs seem to concentrate iodine or these toxic imposters.
Because the iodine can displace these, heavy iodine supplementation can lead to side effects once these start circulating in your body. It is best to start small, work your way up and also support your detoxification pathways when doing so.
Goitrogens, as found in cruciferous vegetables and the rest of the Brassica genus, as well as soy, spinach, strawberries, peaches, peanuts, sweet potatoes, pears and some other foods, can inhibit the uptake of iodine. The good news is that cooking typically inactivates these goitrogens. Unless you have a known thyroid issue or are doing huge amounts of raw foods of this sort, I wouldn’t be too concerned about goitrogens.
How Much Do You Need?
The RDI is 150 mcg. Optimal ranges are higher. Within standard medical practice it is often considered 150-300 mcg.
In some cases people take much higher amounts, up to 15 mg per day. This amount can only really be reached through supplementation or with heavy seaweed use. Some research points to Japanese women consuming up to 13.8 mg of iodine per day, though more common is the 1 to 3 mg range.
Some say that large amounts are necessary. Others say this is dangerous. I’m not sure what the correct answer is, but it appears to be more than the RDI, but probably less than a huge amount. I will say that I advise for any supplemental amounts more than 1 mg, should only be done for a limited time.
My advice is to make sure you take a sufficient amount of iodine supplement so that your body doesn’t uptake the halogens in its place. And it may be worth a period of supplementation to replace the halogens in your body with the iodine that should be there instead.
You can come to know how much iodine you need by finding what is too much, causing a speeding of metabolism and excessive heat generation that comes with it. Back off from this amount and use less.
Different Types
There is iodine (I2) and there is iodide (I-). Both of these are needed for optimal functioning and play different roles in the body. One of the differences is that iodide must be transported into the cells, while iodine simply diffuses into cells. Any supplementation should cover both.
Radioactive iodine (I-131) coming from nuclear accidents is a potential danger. In these cases large supplemental amounts of iodine are taken, most notably as potassium iodide. This way the body doesn’t uptake the radioactive form into its cells as it already has too much available.
Where to get it in diet?
Iodine deficiency leading to goiter is very rare in developed world. It used to be much more common, but this was halted with the iodizing of salt so that one teaspoon of table salt contained almost 400 micrograms of iodine. This salt is used in many processed foods even if you don’t use much table salt.
It is important to note that this salt only contains the iodide form. And probably more important, this salt is best avoided for other reasons, for its lack of other minerals, and the various chemicals and toxins added to it. But because many people do avoid salt for these and other reasons, like hypertension, they are at a greater risk of lack of iodine. Thus, goiter has begun to come back in the US.
It’s important to note that sea salt, Himalayan salt and other more natural forms of salt have only very trace amounts of iodine, much less so than this iodized salt and are not a good source of it.
So where do you get it? Plant based diets tend to have less iodine as it’s found more often in animal foods. They still have some, assuming it is in the soil they grow from in the first place.

Pasture-raised eggs contain more iodine than their commercial version
Dairy products, eggs, fish, shellfish and meat tend to have fair amounts of iodine. In general, healthier versions of these have more. For instance, pasture raised eggs are good sources of iodine. Eating these foods you’ll like reach the RDI but maybe not optimal or therapeutic amounts.
Of note here are all seaweeds which are good sources of iodine, but some are way better than others. For instance, this information mostly from the Maine Coast Sea Vegetables, rates the following based on a seven gram serving of each seaweed:
- Alaria 1162 mcg
- Bladderwrack 3262 mcg
- Dulse 1169 mcg
- Kelp 3170 mcg
- Irish Moss 2796 mcg
- Laver 98 mcg
- Nori 147 mcg
- Sea Lettuce 27 mcg
Thus, bladderwrack, kelp and irish moss come out as our all-star specific mineral superfoods here. Of these, kelp is most often used for this purpose.
It is important to note that about 90% of iodine is excreted in the urine so you need a regular daily supply of this trace mineral.
Supplements
One option is to supplement iodine with powdered kelp. As we’ve seen it is one of the richest seaweeds and is easy to find. Kelp supplements are a very cheap option and can last a long time. Just be sure to get kelp harvested from a pristine place. The great thing is this also supplies other trace minerals.
One of the best iodine supplements Lugol’s solution or Lugol’s iodine, named after the French physician J.G.A. Lugol. This is a mixture of potassium iodide and elemental iodine suspended in solution.
A tablet form of potassium iodide and elemental iodine supplement is available as Iodaral ®. In my opinion the liquid form will absorb better and doesn’t contain fillers.
Another form that has gained popularity was recommend by Edgar Cayce in many of his health readings. This electrified atomic iodine or “Atomidine” was said to be easier for the body to assimilate.
“Within a few weeks…the system will be changed, and also the vibrations through the glandular forces that control the lymph circulation in alimentary canal as well as organs of the pelvis…the Atomidine acts as a gland purifier—causing especially the thyroids and the glands of the stomach, particularly the pyloric portion of the stomach and throughout the duodenum, to change in the form of secretions thrown off—and this affects directly the circulation (3104-1).”
Ratios or Interactions with Other Minerals and Nutrients
Iodine supplements should be taken with enough selenium, typically 200-400mcg per day. This mineral is also necessary for thyroid function.
For best absorption and utilization of iodine you’ll also want magnesium, many other trace minerals, vitamins A, B-complex, D and E, plus the essential fatty acids. So basically everything!
On the flip side, iodine helps with the assimilation and utilization of calcium, phosphorous and silica.
Other Special Notes
Painting your testicles with iodine. Yes, you read that right. This protocol, which involves the use of other nutrients as well to help support detoxification, is meant to specifically displace the toxic halogens that seem to have an affinity for reproductive tissues. By doing this you place the proper iodine back in its place which then will support steroid hormone production. More details are found in Upgrade Your Testosterone.
It’s also been noted that women’s breasts and reproductive tract tend to accumulate iodine, and thus these halogens in their place, possibly having some causal link to breast cancer, ovarian cysts and more. Ingesting as well as topical applications of iodine may be suitable here too. Other people place it over the thyroid on the throat. Be forewarned, this will burn, but it might be worth it, for getting iodine into the places your body needs most.
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Good info.I have been following Mark Wilson’s protocol using Lugols 2% iodine The method is 3 drops under your tongue 1st thing in the morning and at noon with food and then at night I coat my testicles with 3 more drops. I am hoping to get Mr Woody to arise in the mornings like he used to.Been doing this for about 5 days so may be too soon to expect too much.
My question is has anyone else tried this protocol and how long was it before you saw results,thanks.
Best testing method for iodine deficiency and/or surplus.
I appreciate the information everyone has shared here. Does anyone know the most practical and accurate way to find out if I am iodine deficient.
Thanks
There is a urine test that can be done in a lab, but there is also one that can be done at home; it’s less reliable, though:
Get an orange iodine tincture and paint about 3-inch square on your stomach or the inside of a thigh before going to bed. If the color is still the same in the morning, your levels should be OK. If no color remains, you’re most likely deficient in iodine. Do NOT take this tincture orally – it’s poisonous to eat.
p.s.- I also take a couple of drops under the tongue sublingually of a product called Atomidine (sp?). I get it at the better health food store. If you read Brownstein’s books on how IMPORTANT IODINE is, you will appreciate getting enough of it
Thanks for sharing Alex.
Very informative article on Iodine.I’m going to look into “Atomidide”which Casey mentioned.Sounds very interesting.I’ve tried many kinds,Lugols seems to work best for me.As we are all different,I suggest experimenting for each person with each herb or mineral in order to find what works best.I’ve been using myself as a test for over 40 years to find which works best for me.You guys have great products and information.Bruce
I could not agree with that article. Many misleading chapterts here.
Yuo need much more Iodine than RDA. Women need almost 100x RDA. Men 2-4 times less than women. Check stats for breast cancer for Japan women and other coutries.
When you called D. Brownstein, You should mention G. Abraham too
You can’t get iodine from food, if the soil is depleted.
You always need selenium when iodine is taken. When you are selenium deficient you can develop Hashimoto. In many cases Hashimoto will ease when one get gluten free/ in many others when one will get their selenium.
When you have hyperthyroid, you have much severe iodine deficiency. Take mouch more iodine, then introduce lithium and you can recover in over 90% of the cases.Always the right dose is important. Chech for Dr. Jonathan Wright work. Too little is too little, too much is too much and enough is enough
Some organs like iodine, some like iodide. So better to take soething that has both.
Some good points here.
You do need more than RDA, which holds true for most minerals and vitamins. RDA is just what you need for basic survival and it’s not gonna provide you with additional benefits or prevent anything.
Breast cancer is less common in Japan, but there are other factors in play except Iodine deficiency (diet, lifestyle and the fact that Japanese couldn’t use birth control pills until 1999.)
Good point on iodine depleted soil and interesting thoughts on Hashimoto and hyperthyroidism. I’ll definitely check out Dr. Jonathan Wright.
Also just want to point out that it doesn’t seem you read the whole article because we seemed to agree on many of the points you made and they were covered in there.
Great article, Logan. Eminently readable and informative. Agree with Cjack on merits of French Grey/Celtic sea salt, although we still retain some Himalayan Pink in the house for entertainment table use. As for Nascent versus Lugols, perhaps Mark Wilson would care to comment. I believe he has an opinion on this.
Hey man, great article! I would say thought that Nascent Iodine is way better than Lugols and more readily available by the body.
I really loved reading this article thanks
Logan,
Thank you – good info on an element that, I have read, many of us are deficient in. Especially with bromine replacing iodine in bread some decades ago.
Richard
You might want to take a further look at Himalayan (pink) salt – it really isn’t very healthy (all propaganda) and INCREASES the redux potential when put in solution (aka water, like the 70% water if the human body). Thus it oxidizes in the body, ie akin to causing your body to rust.
I’ve seen the independant test for this and REMOVED anything with it in my home years ago. However, a salt that does help is the French Grey sea salt. You may know of one of the highly publicized version of this – namely Celtic Sea Salt.
FYI
I did some searching and this site backed up your claim on celtic sea salt, but there was no mention of himalayan salt being bad for you.
http://authoritynutrition.com/different-types-of-salt/
It’s not bad for you per se, but it lacks sufficient amount of Iodine that table salt provides.
I can vouch for the IODINE protocol. I paint my privates diluted with little bit of water to avoid the sting of Lugols..I also paint my inner thighs with it. At first the yellow tinge disappeared almost instantly because I was that deficient. Now I do it as a maintenance routine once a week. I dont care for sushi or seaweed and dont trust the seaweed in the oceans as non-radioactive, so I take a separate a Triple Iodine supplement too about 3X a week. Radioactive iodine is still in the air from the Japanese reactor meltdown and who knows what other country is releasing radioactive iodine into the air secretly.