Question explored with the scientific record
Iodine liquid
The short version: liquid iodine preparations can push the thyroid into either hyperthyroidism or hypothyroidism, depending on the person's baseline thyroid health and the dose, and the evidence for benefit as a general health supplement is thin.
The evidence here is a collection of case reports and small clinical studies showing that iodine exposure from topical antiseptics, medications, and contrast agents can trigger thyroid dysfunction. A newborn with an omphalocele developed hypothyroidism from povidone-iodine absorbed through the skin during surgical prep [1]. Five adults developed hyperthyroidism after exposure to Betadine, iodo-niacin, amiodarone, or contrast dye [16]. A 33-year-old woman went into thyrotoxicosis after a hysterosalpingography procedure [18]. In a population of Saharawi refugee women with very high iodine in their drinking water, 22% had goiter and 46% had anemia [24]. The mechanism is clear: excess iodine overwhelms the thyroid's autoregulation, especially in people with pre-existing nodules, autoimmune thyroiditis, or iodine deficiency. The mouse studies show that high iodine suppresses DNA repair enzyme MTH1 and causes oxidative DNA damage in thyroid cells [22], and that it disrupts placental deiodinase activity and fetal gene expression [21].
The evidence does not come from manufacturer-funded trials—these are independent clinical reports. But the evidence base is narrow: case series and observational studies, not randomized controlled trials of liquid iodine as a supplement. There is no long-term safety data on daily oral iodine drops or tablets in healthy people. The dose-response is steep and individual. The table below shows the range of thyroid outcomes from the cases in the evidence.
| Iodine exposure source | Thyroid outcome | Population |
|---|---|---|
| Topical povidone-iodine (newborn) | Hypothyroidism | Neonate with omphalocele [1] |
| Betadine, iodo-niacin, amiodarone, contrast | Hyperthyroidism | Adults with/without pre-existing thyroid disease [16] |
| Hysterosalpingography contrast | Hyperthyroidism | 33-year-old woman, previously euthyroid [18] |
| High-iodine drinking water | Goiter (22%), anemia (46%) | Saharawi refugee women [24] |
My call: liquid iodine preparations carry a real and documented risk of thyroid dysfunction that varies unpredictably by individual. The evidence does not support routine use as a health supplement.
Sources examined 29
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Hypothyroidism caused by topical povidone-iodine in a newborn with omphalocele
This case report discusses a newborn with omphalocele who developed physiologic hypothyroidism due to the systemic absorption of povidone-iodine used during surgical preparations.
DOI: 10.1016/s0022-3468(88)80207-0 -
Analysis of angiotensins I, II, III, and iodinated derivatives by high-performance liquid chromatography
This study presents a method for the separation and analysis of angiotensins I, II, and III, as well as their iodinated derivatives, using high-performance liquid chromatography, demonstrating distinct retention times for each peptide.
DOI: 10.1016/0003-2697(81)90292-x -
Methods for measuring iodine in urine and serum
This study evaluates various methods for measuring iodine levels in urine and serum, highlighting the ammonium persulfate oxidation method as a safe and effective alternative to traditional techniques.
DOI: 10.1055/s-0029-1212054 -
Determination of iodine value of palm oil based on triglyceride composition
This study presents a method for determining the iodine value of palm oil based on its triglyceride composition using high-performance liquid chromatography (HPLC), demonstrating a strong predictive capability with high coefficients of determination.
DOI: 10.1007/s11746-998-0227-0 -
Preparative reversed-phase high-performance liquid chromatography of iodinated insulin retaining full biological activity
This study demonstrates the successful separation and isolation of monoiodinated insulin variants using reversed-phase high-performance liquid chromatography (RP-HPLC) while retaining their biological activity, addressing previous concerns about the loss of activity during purif…
DOI: 10.1016/s0021-9673(00)90139-0 -
Radical production in the radiolysis of liquid benzene
Iodine scavenging in gamma-radiolysis of liquid benzene reveals biphenyl yield rising from 0.075 to about 0.38 molecules/100 eV at low iodine and then declining as iodine increases while iodobenzene rises, indicating iodine competes with benzene for phenyl radicals and that the …
DOI: 10.1016/s0969-806x(99)00239-x -
Excretion of iodide in 24-h urine as determined by ion-pair reversed-phase liquid chromatography with electrochemical detection
An accessible ion-pair reversed-phase liquid chromatography method with electrochemical detection for iodide in 24-hour urine is developed and validated against neutron activation analysis, enabling routine estimation of daily iodine intake and assessment of iodization programme…
DOI: 10.1016/s0378-4347(00)83099-6 -
Thermotropic liquid crystalline conjugated polymers, poly(cyclohexylphenoxyacetylenes)-synthesis and properties
Thermotropic liquid-crystalline poly(cyclohexylphenoxyacetylenes) are synthesized via rhodium-, iron-, and molybdenum-catalyzed polymerizations, forming high-molecular-weight polymers that exhibit a smectic A phase, show iodine-doping–induced optical changes, and can be magnetic…
DOI: 10.1016/0379-6779(94)03098-q -
PERBANDINGAN AKTIVITAS ANTIOKSIDAN JAHE EMPRIT (Zingiber officinale var Amarum) DAN JAHE MERAH (Zingiber officinale var Rubrum) DALAM SEDIAAN CAIR BERBASIS BAWANG PUTIH DAN KORELASINYA DENGAN KADAR FENOL DAN VITAMIN C
Garlic-based liquid preparations containing emprit ginger and red ginger show antioxidant activity that strongly correlates with total phenol content, with red ginger having higher phenol and antioxidant metrics, while vitamin C shows no consistent correlation.
DOI: 10.33096/jffi.v6i1.464 -
Speciation of Bio‐Available Iodine in Abalone ( Haliotis discus hannai ) by High‐Performance Liquid Chromatography Hyphenated with Inductively Coupled Plasma‐Mass Spectrometry Using an In Vitro Method
This study investigates the bio-available iodine species in abalone (Haliotis discus hannai) using an in vitro dialyzability method combined with high-performance liquid chromatography and inductively coupled plasma-mass spectrometry, revealing that iodide and 3-iodo-L-tyrosine …
DOI: 10.1111/1750-3841.14173 -
Iodine and creatinine testing in urine dried on filter paper
This study presents a novel method for measuring iodine and creatinine levels in urine dried on filter paper, demonstrating its effectiveness for large-scale population studies and individual assessments of iodine deficiency.
DOI: 10.1016/j.aca.2012.12.021 -
Accuracy of Several Cervical Screening Strategies for Early Detection of Cervical Cancer
This meta-analysis evaluates the accuracy of six cervical cancer screening strategies, revealing that liquid-based cytology (LBC) and visual inspection with Lugol iodine (VILI) are among the most effective methods for early detection of cervical cancer.
DOI: 10.1097/igc.0b013e318256e5e4 -
Lignite sulfur transformation during the supercritical water gasification process
Under the studied SCW gasification conditions, sulfur from lignite is distributed primarily into solid and liquid products, with a small gaseous fraction, and H2S is the only sulfur-containing gas detected; the distribution across phases is influenced by temperature and ER, with…
DOI: 10.1016/j.jaap.2015.09.014 -
Separation of biological variant insulin molecules from different species by reversed-phase high-performance liquid chromatography (HPLC)
This study investigates the separation of insulin molecules from different species using reversed-phase high-performance liquid chromatography (HPLC), highlighting the critical conditions for optimal separation and the effects of temperature and solvent composition on elution ti…
DOI: 10.1016/0006-2944(85)90116-4 -
Free Electron Laser-Polymerization of C60 Grown by Liquid-Liquid-Interfacial Precipitation Method
FEL irradiation under high pressure promotes polymerization of LLIP-grown C60, shown by decreased lattice spacing and Raman Ag(2) red-shifts; iodine hole-doping at 7 GPa further enhances polymerization to a single phase.
DOI: 10.1587/transele.e94.c.151 -
Five patients with iodine-induced hyperthyroidism
This study describes five cases of iodine-induced hyperthyroidism in patients exposed to iodine-containing medications, highlighting the condition's occurrence even in iodine-sufficient areas and the need for cautious use of iodine in patients with thyroid disease.
DOI: 10.1016/0002-9343(84)90726-5 -
Iodine-induced hypothyroidism: a clinical and histological study of 28 patients.
This study examines the clinical and histological characteristics of iodine-induced hypothyroidism in 28 patients, revealing significant histological changes in thyroid specimens associated with excess iodine intake.
DOI: 10.1210/jcem.76.2.8432791 -
Hyperthyroidism secondary to hysterosalpingography
This case report describes a 33-year-old euthyroid woman who developed iodine-induced hyperthyroidism following hysterosalpingography, highlighting a rare complication of the procedure.
DOI: 10.1097/MD.0000000000005588 -
Natural course of iodine-induced thyrotoxicosis (Jodbasedow) in endemic goiter area: A 5 year follow-up
This study investigates the natural course of iodine-induced thyrotoxicosis (Jodbasedow) in a population with endemic goiter in Brazil, revealing that while the condition is rare, it can occur in patients with multinodular goiters following iodized oil treatment, with most cases…
DOI: 10.1007/BF03349973 -
131I-Induced Graves’ disease in patients treated for toxic multinodular goitre: systematic review and descriptive analysis
This systematic review investigates the incidence, risk factors, and clinical outcomes of iodine-induced Graves' disease (131I-IGD) in patients treated for toxic multinodular goitre, revealing a low incidence but significant associations with pre-treatment autoimmune markers.
DOI: 10.1007/s40618-018-0827-y -
Effect of excessive iodine exposure on the placental deiodinase activities and Hoxc8 expression during mouse embryogenesis
Excessive iodine exposure in Balb/C mice perturbs maternal thyroid hormone metabolism by inhibiting hepatic/renal D1, reducing placental D2 activity, and downregulating fetal Hoxc8 expression, suggesting a mechanism for iodine-induced skeletal malformations via thyroid hormone r…
DOI: 10.1017/S0007114507691909 -
High iodine induces DNA damage in autoimmune thyroiditis partially by inhibiting the DNA repair protein MTH1
In a mouse model of autoimmune thyroiditis and in primary mouse thyroid follicular epithelial cells, high iodine induces inflammation, apoptosis, and oxidative DNA damage partially by suppressing the DNA repair enzyme MTH1, and restoring MTH1 mitigates these effects.
DOI: 10.1016/j.cellimm.2019.103948 -
Production of Severe Iodine Deficiency in Sheep Using a Prepared Low-Iodine Diet
This study demonstrates that a specially prepared low-iodine diet can induce severe iodine deficiency in sheep, leading to significant reductions in thyroid hormone levels and growth of wool, alongside the development of goitre.
DOI: 10.1071/bi9800053 -
Iodine-induced goitre and high prevalence of anaemia among Saharawi refugee women
High iodine exposure from drinking water among Saharawi refugee women (15–45 years) is linked to very high urinary iodine concentrations, increased thyroid volume with a substantial goitre prevalence, and a notably high anaemia burden, signaling potential iodine-induced thyroid …
DOI: 10.1017/s1368980011002886 -
Low-Iodine Diet for Producing Iodine Deficiency in Rats
This study developed a low-iodine diet for rats that effectively induced severe iodine deficiency without significantly affecting their growth or reproduction, demonstrating the diet's potential for research on iodine deficiency effects.
DOI: 10.1071/bi9800205 -
Radioactive iodine thyroid uptake in patients with amiodarone-iodine-induced thyroid dysfunction
This study investigates the effects of amiodarone, an iodine-rich drug, on thyroid function, revealing that it can induce both hypothyroidism and thyrotoxicosis, with varying radioactive iodine uptake patterns in affected patients.
DOI: 10.1530/acta.0.1190167 -
Are HCV-infected individuals candidates for hepatitis A vaccine?
The study discusses the impact of increased iodine levels on the incidence of iodine deficiency disorders and highlights the potential for iodine-induced hyperthyroidism following supplementation.
DOI: 10.1016/s0140-6736(05)60597-1 -
Inhibitory and Stimulatory Bystander Effects are Differentially Induced by Iodine-125 and Iodine-123
This study investigates the differential bystander effects induced by iodine-125 and iodine-123 in tumor cells, revealing that iodine-125 causes an inhibitory effect while iodine-123 stimulates the proliferation of neighboring cells.
DOI: 10.1667/RR3567.1 -
Iodine Content of Rat Thyroglobulin Affects its Antigenicity in Inducing Lymphocytic Thyroiditis in the BB/Wor Rat
This study investigates the impact of iodine content in rat thyroglobulin on its antigenicity and the subsequent induction of lymphocytic thyroiditis in BB/Wor rats, revealing that normal iodine thyroglobulin induces thyroiditis in susceptible sublines while low iodine thyroglob…
DOI: 10.3109/08916939209004826