Contains 4% Iodine crystals (99.9%) and 8% Potassium Iodide (USP Grade) in pure distilled water (0.00 ppm TDS). To calculate total iodine content, add grams of elemental iodine to grams of iodide in potassium iodide. This comes out to 101 mg/mL or about 10% total iodine by weight. If one assumes 20 vertical drops for each millilitre, each drop contains about 5 mg of Iodine. Great for water purification, antiseptic for cuts, disinfectant, a biological stain, saltwater aquariums, radioactive iodine uptake inhibitor, and supplementation. Do not put in the mouth without first diluting in your favourite drink. 
You can put a drop or 2 on your skin and see how quickly the red colour disappears to determine qualitatively how deficient you may be without ingesting it. It is estimated that more than 90% of the USA population is deficient. There are several recommendations online, I have found if the iodine spot disappears in 4 to 8 hours, you are highly deficient, in 24 hours, not as deficient. Be aware only 40% or so of the iodine is absorbed that is rubbed on the skin, some comes off and some vaporizes into the air. A great iodine test for deficiency is the "Iodine Loading" test developed by Dr. Abraham which determines at what point you are excreting the same amount of iodine as you are ingesting. 
Potassium Iodide will oxidize into elemental Iodine when left in heat, light, and/or oxygen, sometimes sublimating completely from a container of iodized salt in as little as a year. Because this decomposition has naturally occurred around us over aeons suggests our bodies are familiar with the negatively charged iodide ion and neutral elemental iodine readily provided by Lugol's Solutions. Our cells have an active transport system in place for iodide into each cell. Elemental iodine diffuses into cells without active transport and there are mechanisms in place to reduce elemental iodine to the iodide as well as the reverse in the cell. 
Dr. Lowe, Dr. Brownstein, Dr. Broda Barnes, Dr. Mark Starr, Dr. Tennant et al, are all certified medical Dr.s that have recommended Lugol's Solution as an excellent source of iodine for both types the body can use (iodide and diatomic iodine).
Lugol's iodine, also known as Lugol's solution, first made in 1829, is a solution of elemental iodine and potassium iodide in water, named after the French physician J.G.A. Lugol. Lugol's iodine solution is often used as an antiseptic and disinfectant, for emergency disinfection of drinking water, and as a reagent for starch detection in routine laboratory and medical tests. These uses are possible since the solution is a source of effectively free elemental iodine, which is readily generated from the equilibration between elemental iodine molecules and triiodide ion in the solution.
Please note that this product is prepared by a Professional Degreed Chemist with 33 years of practical experience and training.
The National Institute of Health (NIH) recommends that adults consume 150 micrograms/day of dietary iodine, this is based on being enough to prevent goitre. The longest living population in the world lives in Japan, where dietary iodine levels of 10-20 milligrams/day are common with no water fluoridation. This is about 100X more iodine than recommended by the NIH. Each drop of 3rdI 5% Lugol's Solution contains about 6.3 milligrams of iodine. 97% of all cancer patients are iodine deficient, and up to 95% of Americans are deficient, however, most of us are loaded with fluoride, a nonessential nutrient that is poisonous in small amounts.
For water purification, use 1-5 drops of 5% Lugol's per litre of water depending on how contaminated the water appears to be and wait 30 minutes @ 50 degrees Fahrenheit for the iodine to work. Can be added to tap water before drinking to allow the body to remove toxic halogens and heavy metals.
For cuts or wounds apply enough 5% Lugol's Solution to completely cover affected area, 5% Lugol's Solution will not sting or burn too much because it is made with pure distilled water with no alcohol. Iodine speeds the healing process and can even cause scars to disappear.
To create a dip for corals and their allies, add 0.75 ml (15-20 drops) of Lugol’s per gallon of purified water in a plastic or glass container, then immerse coral completely for 10 - 12 minutes.
Iodine is a key nutrient used to decalcify the pineal gland thereby increasing melatonin, serotonin, and DMT levels in the brain.
Symptoms of iodine deficiency include, among other things, fatigue, cold hands and feet, brain fog, breast fibroids, gastric reflux, polycystic ovarian syndrome, prostitus and depression.
For protection from radioactive fission by-products, the FDA has approved dosages for adults up to 130mg of KI per day. An equivalent dose using 5% Lugols would be 1 millilitre or about 20 drops.  I can make you 5% if you wish, just request at checkout. 
When fully iodine loaded a woman's breasts contain more iodine than the thyroid gland, highlighting the need for supplementing with iodine levels your body can utilize.