Mechanism of Action
Ingested iodine is absorbed in the small intestine as iodide, then actively captured by the thyroid gland through a dedicated transporter (the sodium-iodide symporter, a membrane protein that pumps iodide into thyroid cells). The thyroid concentrates iodine at levels 20 to 50 times higher than blood levels.
Inside the gland, iodide is incorporated into a storage protein called thyroglobulin. This process, known as organification, produces the hormones T4 and T3. T4 circulates in the blood and serves as a reservoir. T3, the biologically active form, is produced locally in target tissues by selenium-dependent enzymes (the deiodinases).
T3 then enters the nucleus of target cells. There, it activates the transcription of genes involved in energy production, protein synthesis and tissue maintenance. This gene-regulatory mechanism explains the thyroid's systemic influence across all organs.
Key Benefits
- Strong
Iodine contributes to the normal production of thyroid hormones and normal thyroid function. This effect is confirmed by decades of research on thyroid physiology and the correction of disorders linked to inadequate intake.
- Strong
Iodine contributes to normal cognitive function. Epidemiological data show that insufficient maternal iodine status during pregnancy is associated with lower cognitive scores in children. This link has been observed in several European cohorts.
- Strong
Iodine contributes to normal energy-yielding metabolism. Thyroid hormones regulate resting energy expenditure, and supplementation in individuals with suboptimal intake improves basal metabolic markers.
- Strong
Adequate iodine intake during pregnancy supports fetal neurodevelopment. The ALSPAC study (a British cohort of over 1,000 mothers) showed an association between low maternal iodine status and lower verbal IQ scores in children at age 8.
- Moderate
Iodine contributes to the normal functioning of the nervous system. Thyroid hormones participate in myelination (formation of the protective nerve sheath) and maintenance of nerve conduction velocity in adults.
- Moderate
Iodine contributes to the maintenance of normal skin. Thyroid hormones support epidermal cell renewal and the regulation of skin hydration.
- Emerging
Emerging data suggest a link between optimal iodine status and the preservation of cognitive functions after age 60. Controlled trials remain limited in this population, however.
Dosage & Forms
Several forms of iodine are available in oral supplementation. Potassium iodide (KI) is the pharmaceutical reference, used in most clinical studies and public health programmes. Sodium iodide offers comparable properties but is less common in formulations. Seaweed extracts (kelp, bladderwrack) provide iodine in organic form, with variable content from batch to batch, making dosing less reproducible.
Recommended daily intake is approximately 150 µg for adults. The upper safety limit is set at 600 µg/day in Europe. The dosage in the Singular formula is expressed in µg and adjusted according to each user's nutritional profile. Potassium iodide was selected for its analytical reproducibility and compatibility with the other bioactives in the formula.
In the Singular Formula
Inclusion rationale
Iodine contributes to normal thyroid function, normal cognitive function and normal energy metabolism. An essential constituent of the thyroid hormones T3 (triiodothyronine) and T4 (thyroxine), iodine holds a central position in regulating the basal metabolism of virtually every cell in the body. The thyroid concentrates circulating iodine to synthesize T4, which is then converted to T3 (the active form) by enzymes called deiodinases, whose activity depends on selenium (also present in the formula). This iodine-selenium synergy is essential for optimal thyroid function. Despite table salt iodization in many countries, nutritional surveys reveal that certain populations remain at suboptimal intake, particularly people limiting their consumption of salt, dairy or fish. Thyroid function directly influences thermogenesis, heart rate, cell renewal and cognitive functions. Its progressive decline with age makes monitoring iodine status particularly relevant from a longevity perspective. Potassium iodide form, stable and well absorbed.
Selected form
Potassium iodide (KI), synthesised in Europe. Potassium iodide is the most stable and bioavailable form of iodine in oral supplementation. Its high water solubility (1,440 g/L) ensures homogeneous dispersion in the formula. Iodine contributes to normal thyroid function and normal cognitive function. Quality: vegan, non-GMO, allergen-free, residual solvent-free, Kosher certified.
Formula dosage
0 to 150 µg.
Synergies in the formula
Linked Biomarkers
Safety & Precautions
Iodine in oral supplementation is well tolerated at nutritional doses (up to 150-200 µg/day). The upper safety limit established by European authorities is 600 µg/day for adults. Chronic iodine excess can disrupt thyroid function, particularly in individuals with a pre-existing thyroid vulnerability.
Iodine supplementation is not recommended in cases of uncontrolled hyperthyroidism, active autoimmune thyroiditis or use of thyroid medications (levothyroxine, antithyroid drugs) without prior medical advice. Individuals taking amiodarone or lithium should consult a healthcare professional before supplementing.
During pregnancy and breastfeeding, iodine requirements increase (200-250 µg/day per European recommendations). Any supplementation during these periods should be validated by a healthcare professional. In children and adolescents, intake should be adapted to the age group.
The safety profile of potassium iodide has been documented for over a century. Adverse effects at nutritional doses remain exceptional.
Scientific Studies
| Authors | Year | Type | Journal | |
|---|---|---|---|---|
| Zimmermann MB, Boelaert K | 2015 | Systematic Review | Lancet Diabetes & Endocrinology | View on PubMed |
Iodine deficiency and thyroid disorders Comprehensive review of thyroid disorders linked to insufficient iodine intake, covering global epidemiology, pathophysiological mechanisms and prevention strategies through salt iodisation. | ||||
| Bath SC et al. | 2013 | Cohort Study | The Lancet | View on PubMed |
Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC) British cohort study of over 1,000 mother-child pairs showing that insufficient maternal iodine status in the first trimester is associated with lower verbal IQ and reading comprehension scores in children at age 8-9. | ||||
| Harding KB et al. | 2017 | Meta-analysis | Cochrane Database of Systematic Reviews | View on PubMed |
Iodine supplementation for women during the preconception, pregnancy and postpartum period Cochrane meta-analysis evaluating the efficacy and safety of iodine supplementation in women before, during and after pregnancy. Data confirm improved maternal iodine status. | ||||
| Taylor PN et al. | 2018 | Systematic Review | Nature Reviews Endocrinology | View on PubMed |
Global epidemiology of hyperthyroidism and hypothyroidism Review of the global epidemiology of thyroid dysfunction, documenting the relationship between population iodine status and the prevalence of hypothyroidism and hyperthyroidism. | ||||
| Farebrother J et al. | 2019 | Systematic Review | Annals of the New York Academy of Sciences | View on PubMed |
Excess iodine intake: sources, assessment, and effects on thyroid function Review of excess iodine sources, assessment methods and effects on thyroid function, useful for understanding the safety limits of supplementation. | ||||
| Zimmermann MB | 2009 | Systematic Review | Endocrine Reviews | View on PubMed |
Iodine deficiency Landmark review covering iodine biochemistry, the consequences of insufficient intake on brain development and thyroid, and global salt iodisation programmes. | ||||