Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for IODINE are as follows:
More evidence is needed to rate the effectiveness of iodine for these uses.
ADULTS
BY MOUTH:
ON THE SKIN:
CHILDREN
BY MOUTH:
AS EYE DROPS:
The National Institute of Medicine has set Adequate Intake (AI) of iodine for infants: 0 to 6 months, 110 mcg/day; 7 to 12 months, 130 mcg/day.
For children and adults, Recommended Dietary Amounts (RDA) have been set: children 1 to 8 years, 90 mcg/day; 9 to 13 years, 120 mcg/day; people age 14 and older, 150 mcg/day. For pregnant women, the RDA is 220 mcg/day, and breastfeeding women, 290 mcg/day.
Tolerable Upper Intake Levels (UL), the highest level of intake that is not likely to cause unwanted side effects, for iodine intake have been set: children 1 to 3 years, 200 mcg/day; 4 to 8 years, 300 mcg/day; 9 to 13 years, 600 mcg/day; 14 to 18 years (including pregnancy and breastfeeding), 900 mcg/day. For adults older than age 19 including pregnant and breastfeeding women, the Tolerable Upper Intake Level is 1100 mcg/day.
Iodine can cause side effects in some people. Common side effects include nausea and stomach pain, runny nose, headache, metallic taste, and diarrhea.
In sensitive people, iodine can cause side effects including swelling of the lips and face (angioedema), severe bleeding and bruising, fever, joint pain, lymph node enlargement, hives, and death. However, such sensitivity is very rare.
Large amounts or long-term use of iodine are POSSIBLY UNSAFE. Adults should avoid prolonged use of doses higher than 1100 mcg per day (the upper tolerable limit, UL) without proper medical supervision. In children, doses should not exceed 200 mcg per day for children 1 to 3 years old, 300 mcg per day for children 4 to 8 years old, 600 mcg per day for children 9 to 13 years old, and 900 mcg per day for adolescents. These are the upper tolerable limits (UL).
In both children and adults, there is concern that higher intake can increase the risk of side effects such as thyroid problems. Iodine in larger amounts can cause metallic taste, soreness of teeth and gums, burning in mouth and throat, increased saliva, throat inflammation, stomach upset, diarrhea, wasting, depression, skin problems, and many other side effects.
When iodine is used directly on the skin, it can cause skin irritation, stains, allergic reactions, and other side effects. Be careful not to bandage or tightly cover areas that have been treated with iodine to avoid iodine burn.
Pregnancy and breast-feeding: Iodine needs increase during pregnancy. Iodine is LIKELY SAFE when taken by mouth in recommended amounts or when applied to the skin appropriately using an approved product (2% solution). Iodine is POSSIBLY UNSAFE when taken by mouth in high doses. Do not take more than 1100 mcg of iodine per day if you are over 18 years old; do not take more than 900 mcg of iodine per day if you are 14 to 18 years old. Higher intake has been shown to cause thyroid problems in the newborn in some cases.
Autoimmune thyroid disease: People with autoimmune thyroid disease may be especially sensitive to the harmful side effects of iodine.
A type of rash called dermatitis herpetiformis: Taking iodine can cause worsening of this rash.
Thyroid disorders, such as too little thyroid function (hypothyroidism), an enlarged thyroid gland (goiter), or a thyroid tumor: Prolonged use or high doses of iodine might make these conditions worse.
Some of these medications include methenamine mandelate (Methimazole), methimazole (Tapazole), potassium iodide (Thyro-Block), and others.
Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), lisinopril (Prinivil, Zestril), ramipril (Altace), and others.
The ARBs include losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro), candesartan (Atacand), telmisartan (Micardis), and eprosartan (Teveten).
Some “water pills” that increase potassium in the body include spironolactone (Aldactone), triamterene (Dyrenium), and amiloride (Midamor).