Is L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo-? Is L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- safe for nursing mother and child? Does L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- extracts into breast milk? Does L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- has any long term or short term side effects on infants? Can L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- influence milk supply or can L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- decrease milk supply in lactating mothers?

Synthetic preparation of human thyroid hormone T3 used in the treatment of hypothyroidism. Since the last update, we have not found published data on its excretion in breast milk. T3 is a natural component of breast milk, found in small concentrations that may or may not depend on plasma levels (Zhang 2013, Oberkotter 1989, Jansson 1983, Mizuta 1983, Sato 1979). Its concentration in breast milk is much higher than that of levothyroxine (T4), which is usually undetectable (Jansson 1983, Sato 1979). Until there is more published data on this drug in relation to breastfeeding, safer known alternatives (levothyroxine) may be preferable, especially during the neonatal period and in case of prematurity. Associations which are experts in thyroid diseases recommend treatment with levothyroxine in breastfeeding mothers affected by hypothyroidism (Alexander 2017).

L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- (T3) is a normal component of human milk. If replacement doses of L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- are required by the mother, it is not necessarily a reason to discontinue breastfeeding. However, because no information is available on the use of exogenous L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- during breastfeeding, an alternate drug may be preferred. The American Thyroid Association recommends that subclinical and overt hypothyroidism should be treated with levothyroxine in lactating women seeking to breastfeed.[1] L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- dosage requirement may be increased in the postpartum period compared to prepregnancy requirements patients with Hashimoto's thyroiditis.[2]

Relevant published information was not found as of the revision date. However, the thyroid hormone content of human milk from the mothers of very preterm infants appears not to be sufficient to affect the infants thyroid status.[10]

Adequate thyroid hormone serum levels are required for normal lactation. Replacing deficient thyroid levels should improve milk production caused by hypothyroidism. Supraphysiologic doses of L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo- would not be expected to further improve lactation.