Lactoferrin's primary hormonal relevance is through iron metabolism — thyroid peroxidase (the enzyme producing thyroid hormones T3 and T4) is iron-dependent. Iron deficiency impairs thyroid hormone synthesis. Lactoferrin's iron regulation may support thyroid function in iron-deficient individuals. No significant estrogenic, androgenic, or cortisol-modifying activity has been documented at therapeutic doses.

Does lactoferrin affect thyroid antibodies in Hashimoto's?

No documented direct effect on thyroid antibodies (TPO-Ab, TG-Ab). The anti-inflammatory effects might theoretically reduce autoimmune inflammatory activity, but no Hashimoto's-specific data exists.

Can women with hormone-sensitive cancers (ER+ breast cancer) use lactoferrin?

Lactoferrin has no estrogenic activity. Oncology consultation is always recommended for individuals with hormone-sensitive cancers considering any new supplement, but lactoferrin specifically has no documented estrogenic concern.