Lugol's Iodine Solution: History, Tradition and the Research of Dr David Brownstein and Dr Guy Abraham
Lugol's iodine is one of the oldest continuously used preparations in medicine. Formulated in 1829 by the French physician Jean Guillaume Auguste Lugol, it has been part of mainstream clinical practice, traditional use and self-care for nearly two centuries. In more recent decades, two researchers - Dr David Brownstein and Dr Guy Abraham - have written extensively about iodine sufficiency and the role they believe Lugol's plays in supporting it. This article covers the history of the preparation itself, the work of both researchers, and where to find the formulation they referenced.
What is Lugol's iodine?
Lugol's solution is an aqueous preparation containing elemental iodine and potassium iodide, dissolved in water. The standard formula established by Lugol in the 19th century combines both forms: elemental iodine (I2) and potassium iodide (KI). The potassium iodide serves partly as a solubilising agent, making the iodine miscible in water, and partly as a separate source of iodide - a chemically distinct form.
The two percentage strengths available from Health Leads - 5% and 12% - refer to the iodine content by volume. The 5% solution contains approximately 6.25mg of total iodine per drop (combining both elemental iodine and iodide), while the 12% solution contains a higher concentration per drop. Both are the same preparation at different strengths.
Lugol's was listed in the British Pharmacopoeia from the 19th century into the mid-20th century, used in thyroid preparation before surgery, for wound antisepsis, and in a range of clinical applications. In the United States it was used extensively in conventional medical practice up to and through the Second World War.
Iodine and the body: a brief background
Iodine is an essential trace mineral - the body cannot synthesise it and must obtain it through diet or supplementation. Its best-understood role is in thyroid hormone production: the thyroid gland incorporates iodine into the hormones thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, energy, and development. The established UK reference nutrient intake (RNI) is 150 micrograms (mcg) per day for adults.
However, iodine is present in tissues beyond the thyroid - including the breast, prostate, ovaries, and gastric mucosa - and researchers have debated whether the thyroid-focused RNI reflects the requirements of the whole body. This debate is at the core of the work of both Dr Brownstein and Dr Abraham.
Who was Dr Guy Abraham?
Dr Guy E. Abraham is a former professor of obstetrics, gynaecology and endocrinology at the UCLA School of Medicine. He left academic practice to found Optimox Corporation, a supplement research and manufacturing company, and in 1997 he launched what he called the Iodine Project - a research initiative investigating the hypothesis that the current recommended daily intake of iodine was significantly below what the body required for whole-body sufficiency.
Abraham's central argument, set out across a series of papers published from 2002 onwards, was that the body as a whole - not just the thyroid - retains iodine across multiple tissues, and that the amount of iodine needed to achieve sufficiency across all those tissues is far higher than the 150mcg RNI suggests. He developed what he called the iodine-loading test: administering a 50mg dose of Lugol's and measuring how much iodine was excreted in urine over the following 24 hours. In Abraham's framework, excreting 90% or more of the dose indicated sufficiency; excreting less indicated the body was retaining iodine because tissue levels were depleted.
Abraham coined the term medical iodophobia to describe what he characterised as the medical profession's post-war reluctance to use iodine at the doses historically employed. He argued that physicians before the Second World War routinely used Lugol's at doses of 6mg to 37mg per day - well above the RNI - and that this practice was abandoned not on safety grounds but as a result of the introduction of synthetic thyroid medications, which made iodine supplementation commercially less interesting.
He worked closely with two other physicians - Dr Jorge Flechas and Dr David Brownstein - who independently began testing and using higher-dose Lugol's in clinical practice and reported their observations.
Who is Dr David Brownstein?
Dr David Brownstein is a board-certified family physician and Medical Director of the Center for Holistic Medicine in West Bloomfield, Michigan. He has practised integrative and holistic medicine since the 1990s and has written a series of books on nutritional approaches to health.
His most directly relevant title is Iodine: Why You Need It, Why You Can't Live Without It, first published in 2004 and now in its fifth edition. In it, Brownstein describes his clinical observations from testing iodine levels in patients attending his practice, and the role he believes iodine plays in supporting thyroid function, breast health, and overall wellbeing.
In his own words, from Iodine: Why You Need It, Why You Can't Live Without It (5th edition):
After testing over 5,000 patients, I found that approximately 96% were low in inorganic iodine.
He attributed this widespread deficiency in part to changes in the food supply - specifically the replacement of iodine with bromine as a dough conditioner in commercial bread production in the 1960s. Iodine and bromine compete for the same receptors in the body; bromine, in Brownstein's view, not only failed to deliver iodine's benefits but actively displaced it from tissues.
Brownstein also referenced data from the US National Health and Nutrition Examination Survey (NHANES) showing that iodine levels in the US population fell by approximately 50% between the 1970s and the early 2000s - a period corresponding to the shift away from iodine in bread. He argued this population-level decline in dietary iodine, combined with widespread exposure to bromine and other halides, had created a degree of deficiency that the RNI was not designed to address.
On the question of dose, Brownstein was explicit that he used Lugol's at levels higher than the RNI - typically starting at 6.25mg per day (one drop of 5% Lugol's) and working upwards under physician supervision, ranging from 6mg to 50mg daily depending on the individual. He did not recommend self-prescribing at higher doses and consistently emphasised that clinical use of higher-dose iodine should be supervised by a practitioner familiar with iodine physiology.
He also noted that a co-factor protocol - including selenium, magnesium, and B vitamins - was important alongside iodine supplementation to support the pathways through which the thyroid processes and activates iodine.
Where Abraham and Brownstein diverge slightly
Abraham and Brownstein shared the core premise - that iodine deficiency is widespread and that the RNI significantly underestimates whole-body requirements - but came at it from slightly different angles.
Abraham was primarily a researcher and biochemist. His contribution was the theoretical framework (whole-body iodine sufficiency), the loading test methodology, and the published papers providing a scientific basis for the clinical observations. He was the originator of the Iodine Project and provided the intellectual scaffolding on which clinical practitioners like Brownstein could build.
Brownstein was primarily a clinician. His contribution was the clinical observation record - patients tested and followed in practice - and the lay-accessible writing that brought these ideas to a general audience. His books are widely read in the integrative health community in both the US and the UK.
Brownstein has also been more publicly visible: he appeared in several documentary films on iodine and held regular educational conferences. It is worth noting that in 2020 he received a warning letter from the US Federal Trade Commission regarding claims made about COVID-19 treatments - those claims were unrelated to iodine or nutritional supplementation, and do not bear on his research or clinical writing specifically about iodine.
What does this mean for Lugol's iodine use?
The debate about iodine dosing sits firmly in the grey area between established medicine and integrative practice. The official UK position is that 150mcg per day is the recommended intake for adults; the EFSA authorised health claim for iodine relates to its contribution to normal thyroid function and normal energy-yielding metabolism.
The position of Brownstein and Abraham - that whole-body iodine sufficiency may require substantially more than this, and that Lugol's solution is an appropriate vehicle for achieving it - is not endorsed by UK or EU regulatory bodies and has not been established in large-scale clinical trials.
What is documented is that Lugol's iodine was used extensively in conventional medicine for more than a century, that iodine as a mineral is essential for thyroid hormone production, and that both researchers cited a body of historical and observational data in support of their position. Their work is reported here as a matter of record, not as endorsement.
Anyone considering iodine supplementation - particularly at levels above the UK RNI - should consult their GP or a qualified healthcare professional. Iodine supplementation is not appropriate for everyone: individuals with hyperthyroidism or Hashimoto's thyroiditis should take particular care, and anyone on thyroid medication should discuss iodine supplementation with their prescribing physician before beginning.
Lugol's iodine at Health Leads UK
We stock Lugol's iodine in both concentrations discussed by Brownstein and Abraham:
Lugol's Iodine 5% Solution - the more commonly used starting-point concentration. Each drop contains approximately 6.25mg of combined iodine and iodide. This is the strength most commonly referenced in introductory iodine protocols.
Lugol's Iodine 12% Solution - a higher-concentration formulation for those already familiar with Lugol's use. Available in 30ml and 100ml bottles. Each drop contains approximately 15mg of combined iodine and iodide.
Both solutions contain only iodine and potassium iodide in purified water - no added preservatives, flavourings or carriers.
Brownstein noted in his clinical writing that selenium and magnesium are important co-factors for iodine metabolism. We also stock Selenium 200mcg (L-Selenomethionine) and a range of magnesium formulations for those following a broader nutritional protocol.
A note on use
Lugol's iodine is a supplement, not a medicine, and is sold as such. It should not be used as a substitute for medical treatment. The doses described in the research of Brownstein and Abraham - typically 6.25mg to 50mg per day - are considerably higher than the UK RNI of 150mcg and are not endorsed by UK or European health authorities.
If you are new to Lugol's iodine, starting with the 5% solution and a low dose (one drop per day) is the conventional approach in the integrative community. Progression in dose, if undertaken, should be done gradually and under appropriate guidance.
Food supplements should not be used as a substitute for a varied diet and healthy lifestyle.