Most forum users use Lugol's, Iodoral, or nascent Iodine (also called detoxified iodine or Atomidine). Please scroll to the end to read the post on Iodine vs. Iodide.
Formulation: Iodine 5% + Potassium Iodide (KI) 10% in distilled water. Traditionally used over the last 100 years. Stains badly, unpleasant taste, can cause gastric irritation. Can be used orally or applied to skin (painting). A "drop" is 6.5mg and two drops = approximately 12.5 mg (5 mg iodine, 7.5 mg iodide) or equal to 1 tab Iodoral. Due to recent FDA changes, Lugol's is now available in a lesser formulation..
The tablet form of Lugol's (5%). [Formulation: 5 mg iodine + 7.5 mg potassium Iodide + colloidal silicon excipient + thin film of pharmaceutical glaze.] 1 tablet = 2 drops Lugol's = 12.5 mg iodine (5 mg iodine + 7.5 mg potassium iodide). Convenient, clean, easy to measure. More expensive than Lugol's
Atomidine One of the Edgar Cayce iodines. 1 drop (0.06 mL) = 600 mcg iodine (from Iodine Trichloride).
This form is given to protect people from radiation fallout.
Potassium Iodide (KI) Potassium Iodide is a basic salt made of potassium and iodine. Its symbol is KI (K = Potassium, I = Iodine). It is a commonly available supplement and comes in various strengths; e.g., 225 mcg, 32.5 mg, 65 mg. The Iodide form is believed to be particularly useful for the thyroid. It is not the supplement of choice for the breast since the breast prefers “iodine” not “iodide.”
Not fot oral use. Good for painting or adding to bath water.
Not for oral use, contains alcohol. Could be used for painting.
Most elements don't occur alone in their elemental forms in nature, but rather are combined with others, common exceptions being gold, silver, copper, Elements in the first two columns on the left of the periodic table are metals, including sodium, potassium, rubidium, cesium, lihium, magnesium, calcium, strontium. But these are active metals, they like to give away an negatively charged electron and in so doing, themselves become positive ions, and are called "cations" . Meeeeoooooowww. (insert Cat Scratch Fever video here)
Elements of the halogen family in the penultimate right column on the other side of the periodic table, such as individual iodine atoms, are deficient in electrons and want to absorb one. When they absorb one, they become negatively charged ions, and are called "anions". They are so lonely, they will even pair up with one another and share some of their electrons, just so they can each have more electrons. This is why fluorine, chlorine, bromine and iodine exist as diatomic molecules, with two atoms comprising each molecule.
Now to answer the question.
There are two common forms of iodine. One is diatomic iodine, with two atoms comprising an I2 molecule. The other form is iodide anion, which has received an electron from another atom in the world. It could be a potassium atom. If you put potassium and iodine together, the potassium will give its electron to iodine and form a positively-charged potassium cation and a negatively-charged iodide anion, and you will have potassium iodide. When you do this, sparks fly, and I mean literally. Sodium chloride, which is table salt , is analogous.
Iodine exists in another form, which is called tri-iodide anion. This is made by combining one iodide anion with one diatomic iodine molecule. The resulting anion carries a single negative charge and has three iodine atoms attached to one another in substantially linear configuration. To balance the charge, a cation must be present, such as potassium.
When Lugol's is made, an aqueous soluiton of Potassium Iodide (LI) is prepared by dissolving KI in water, say ten grams KI in 85 grams water. Then, once dissolved, five grams of iodine crystals are added to the Potassium Iodide solution. The diatomic iodine adds to the iodide ions in the KI solution to form potassium tri-iodide, which is what Lugol's solution REALLY is.
Tri-iodide is stable, but when diluted it disproportionates back to iodide ions and elemental iodine. So, by ingesting diluted Lugol's iodine, a test subject will be provided with both iodied and elemental iodine.
The elemental iodine itself can react with water to form hydriodic acid and hypoiodous acid, and with potassium present there will be a complex mixture present, but one need not be too concerned with the equilibria associated with these. Suffice it, that Lugol's solution is REALLY a solution of potassium tri-iodide, which contains both iodide ions and elemental iodine, in a married form.
Studies have shown that elemental iodine seems to have benefits that iodide alone does not, I believe it was Ghent and Hill, while working in the Mimetix study.
from "Iodine, Why You Need It, Why You Can't Live Without It" David Brownstein, MD
"It was thought that the intestinal tract could easily convert iodine to iodide, but research has shown this is not true. Different tissues of the body respond to different forms of iodine. The thyroid gland primarily utilizes ioDIDE....the breasts, on the other hand, primarily utilize ioDINE....
Because different tissues concentrate different forms of iodine, using a supplement that contains both iodine and iodide is preferable to using a supplement that contains only one form, As mentioned above, the breasts concentrate iodine. The prostate gland concentrates iodine. The thyroid gland and the skin primarily concentrate iodide. Other tissues, including the kidneys, spleen, liver, blood, salivary glands and intestines can concentrate either form. With different tissues responding to different forms of iodine, it would make common sense that a greater therapeutic benefit from iodine will be achieved by using a COMBINATION OF IODINE AND IODIDE. My clinical experience has proven, beyond a doubt, that a combination of IODINE/IODIDE (e.g., Lugol's or Iodoral) is much more effective than an iodide only supplement(e.g., SSKI and most other liquid iodide formulations)."