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Iodine Study #21

The Iodine/Iodide Loading Test

Important Information

This test is used to assess whole body sufficiency for the essential element iodine. It is recommended prior to and following 3 months on orthoiodosupplementation.


Orthoiodosupplementation is the daily amount of the essential element iodine needed for whole body sufficiency (1). Whole body sufficiency for iodine is assessed by an iodine/iodide loading test (2). The test consists of ingesting 4 tablets of a solid dosage form of Lugol (Iodoral®), containing a total of 50 mg iodine/iodide. Then urinary iodide levels are measured in the following 24 hr collection. The iodine/iodide loading test is based on the concept that the normally functioning human body has a mechanism to retain ingested iodine until whole body sufficiency for iodine is achieved. During orthoiodosupplementation, a negative feedback mechanism is triggered that progressively adjusts the excretion of iodine to balance the intake. As the body iodine content increases, the percent of the iodine load retained decreases with a concomitant increase in the amount of iodide excreted in the 24 hr urine collection. When whole body sufficiency for iodine is achieved, the absorbed iodine/iodide is quantitatively excreted as iodide in the urine (1- 3). In the U.S. population, the percent of iodine load excreted in the 24 hr urine collection prior to orthoiodosupplementation averages 40% in more than 7,000 loading tests performed at the FFP Laboratories.

After 3 months of supplementation with 50 mg iodine/iodide/day, (4 tablets of Iodoral®) most non-obese subjects not exposed to excess goitrogens achieved whole body iodine sufficiency, arbitrarily defined as 90% or more of the iodine load excreted in the 24 hr urine collections (2,4). Adult subjects retained approximately 1.5 gm of iodine when they reach sufficiency (3). A repeat loading test following 3 months on orthoiodosupplementation is recommended. The goal of orthoiodosupplementation is not the treatment of disease, but the supply of optimal amounts of an essential nutrient for whole body sufficiency and for optimal mental and physical performances. Whole body sufficiency for iodine correlates well with overall wellbeing, and some subjects could tell when they achieved sufficiency even before knowing the results of the test. Iodine sufficiency was associated with a sense of overall wellbeing, lifting of a brain fog, feeling warmer in cold environments, increased energy, needing less sleep, achieving more in less time, experiencing regular bowel movements and improved skin complexion (2). Whole body iodine deficiency, based on the concept of orthoiodosupplementation, may play an important role in several clinical conditions (5). Hundreds of physicians and other health care providers are now using the loading test and implementing orthoiodosupplementation in their practice, using a tablet form of Lugol (Iodoral®). A very good correlation between the results of the loading test and clinical response of their patients to iodine supplementation was reported (6,7). For consistency and reproducibility of results, the same Lugol tablets are used in the loading test and in the orthoiodosupplementation program.

Procedure for the loading test

A good lab to perform the iodine/iodide loading test is Doctor's Data, Inc. in St. Charles, IL. They supply their own protocol for details on collection of urine samples, pooling samples for 24 hr. and sending a 2 ounce aliquot to the Laboratory for analysis. We recommend this general outline:

  1. Have patient stop ingesting iodine 24 to 48 hours before the test if post- supplementation.
  2. Discard first morning void;
  3. Take 4 tablets of Iodoral®;
  4. Start collection of urine, following instructions from the Lab that supplied you with the Kit;
  5. The first void on the following morning should be included in the urine collection;
  6. If total urine volume is above 3 liters, follow instructions supplied with the Kit.

Doctor's Data, Inc.
3755 Illinois Avenue
St. Charles, IL 60174-2420
Phone: 630 377-8139
Toll Free: 800 323-2784
Fax: 630 587-7860


  1. Abraham, G.E., Flechas, J.D., Hakala, J.C., Orthoiodosupplementation: Iodine Sufficiency of the Whole Human Body. The Original Internist, 9:30-41, 2002.
  2. Abraham, G.E., The safe and effective implementation of orthoiodosupplementation in medical practice. The Original Internist, 11:17-36, 2004.
  3. Abraham, G.E., The concept of orthoiodosupplementation and its clinical implications. The Original Internist, 11:29-38, 2004.
  4. Abraham, G.E., The historical background of the iodine project. The Original Internist, 12(2):57-66, 2005.
  5. Abraham, G.E., Iodine: The Universal Nutrient.Townsend Letter, 269:85-88, 2005
  6. Flechas, J.D., Orthoiodosupplementation in a primary care practice. The Original Internist, 12(2):89-96, 2005.
  7. Brownstein, D., Clinical experience with inorganic, non-radioactive iodine/iodide. The Original Internist, 12(3):105-108, 2005.