The effect of iodine in patients using povidone-iodine mouth wash on thyroid function


  • Gowri Shankar Murugesan Department of Otorhinolaryngology and Head and Neck Surgery, Government Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
  • Manju Priya Venkat Department of Otorhinolaryngology and Head and Neck Surgery, Government Stanley Medical College and Hospital, Chennai, Tamil Nadu, India



Povidone-iodine, Thyroid function, Thyroid stimulating hormone


Background: Thyroid gland is a key part of endocrine system and it performs its functions via two most important thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid gland is mainly regulated by thyroid-stimulating hormone (TSH). Povidone-iodine (polyvinylpyrrolidone-iodine, PVP-I) mouthwash is commonly used to treat infections of the oral cavity and oropharynx and iodine released from PVP-I can interfere with thyroid function. In this study the effect of brief treatment with povidone-iodine mouth wash on thyroid function was assessed. The aim of the present study was to assess whether iodine is absorbed through oral transmucosal route and interfere with TSH in serum.

Methods: Fifty one patients with acute and chronic pharyngitis and tonsillitis were recruited and out of which forty-seven patients were treated with 20 ml of PVP-I mouthwash twice daily for 3 weeks and blood was collected from the respective patients before and after treatment with PVP-I. Serum thyroid stimulating hormone concentration was measured from the collected blood samples of the patients.

Results: In the present study there was a small increase in serum TSH concentration during the therapy with PVP-I but the concentration determined was within the normal range.

Conclusions: Based on the results of this study we conclude that the use of PVP-I for a brief period transiently increase TSH value and prolonged use should be avoided in people with an increased risk of thyroid dysfunction and other autoimmune disorders.


Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014;10(3):136-4

Rousset B, Dupuy C, Miot F, Dumont J. Thyroid hormone synthesis and secretion. In: Feingold KR, Anawalt B, Boyce A, eds. South Dartmouth: Endotext, MDText. com, Inc; 2015.

Mariotti S, Beck-Peccoz P. Physiology of the hypothalamic-pituitary-thyroid axis. In: Feingold KR, Anawalt B, Boyce A, eds. South Dartmouth: Endotext, MDText. com, Inc; 2016.

Wolff J. Excess iodide inhibits the thyroid by multiple mechanisms. Adv Exp Med Biol. 1989;261:211-44.

Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-induced hypothyroidism. Thyroid. 2001;11(5):501-10.

Sato K, Ohmori T, Shiratori K, Yamazaki K, Yamada E, Kimura H, et al. Povidone iodine-induced overt hypothyroidism in a patient with prolonged habitual gargling: urinary excretion of iodine after gargling in normal subjects. Intern Med. 2007;46(7):391-5.

Leung AM, Braverman LE. Iodine-induced thyroid dysfunction. Curr Opin Endocrinol Diabetes Obes. 2012;19(5):414-9.

Katagiri R, Yuan X, Kobayashi S, Sasaki S. Effect of excess iodine intake on thyroid diseases in different populations: A systematic review and meta-analyses including observational studies. PLoS One. 2017;12(3):e0173722.

Lachapelle JM, Castel O, Casado AF, Leroy B, Micali G, Tennstedt D et al. Antiseptics in the era of bacterial resistance: a focus on povidone iodine. Clin Pract. 2013;10(5):579.

Chung HR. Iodine and thyroid function. Ann Pediatr Endocrinol Metab. 2014;19(1):8-12.

Kohler S, Senn O, Saleh L, Wass JAH, Schmid CH. Timing of thyroxine dose adjustment in hypothyroid patients: when are TSH levels stable?. J Thyroid Disord Ther. 2014;3(3):1000161.

Pirahanchi Y, Jialal I. Physiology, Thyroid Stimulating Hormone (TSH). In: Stevenson RL, Pratt H, ed. Treasure Island. StatPearls Publishing; 2019.

Ader AW, Paul TL, Reinhardt W, Safran M, Pino SAM, Mcarthur W, et al. Effect of mouth rinsing with two polyvinylpyrrolidone-iodine mixtures on iodine absorption and thyroid function. J Clin Endocrinol Metab. 1988;66(3):632-5.

Nobukuni K, Hayakawa N, Namba R, Ihara Y, Sato K, Takada H, et al. The influence of long-term treatment with povidone-iodine on thyroid function. Dermatol. 1997;195(S2):69-72.

Nobukuni K, Kawahara S. Thyroid function in nurses: the influence of povidone-iodine hand washing and gargling. Dermatol. 2002;204(S1):99-102.

Findik RB, Yilmaz G, Celik HT, Yilmaz FM, Hamurcu U, Karakaya J. Effect of povidone iodine on thyroid functions and urine iodine levels in caesarean operations. J Matern Neonatal Med. 2014;27(10):1020-2.

Tomoda C, Kitano H, Uruno T, Takamura Y, Ito Y, Miya A, et al. Transcutaneous iodine absorption in adult patients with thyroid cancer disinfected with povidone-iodine at operation. Thyroid. 2005;15(6):600-3.






Original Research Articles