You should not take green tea extract and iron together. Green tea contains a compound that binds to iron. When consumed together, green tea extract loses its antioxidant potential, and iron absorption is severely reduced [1].
To avoid this, consider taking green tea supplements two hours before or after eating iron-rich foods like meat, poultry, shellfish, beans, tofu, and fortified breakfast cereals.

References
Fan F. S. (2016). Iron deficiency anemia due to excessive green tea drinking. Clinical case reports, 4(11), 1053–1056. https://doi.org/10.1002/ccr3.707
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