Can a tea bag only be used once?

From the perspective of nutrient absorption, it is best to brew a tea bag only once, and not more than three times for loose tea.

Tea bags are relatively common in life. Since tea bags are secondary processing, the ideal way to treat tea bags is to brew them only once. However, repeated brewing of tea leaves will also gradually leach some insoluble harmful substances, such as very small amounts of residual pesticides.