It should be noted that you must not drink overnight tea. In addition, the temperature is generally high in summer, so tea should not exceed 12 hour. You can't make tea in a thermos cup to avoid the loss of nutrients.
Berberine and tea cannot be eaten at the same time. Do not drink tea within 2 hours before and after taking berberine. Tea contains about 10% tannin, which is an alkaloid precipitant, and can combine with alkaloids in berberine to form insoluble tannin precipitate, which reduces the efficacy of berberine. Drinking tea on an empty stomach will dilute the gastric juice, leading to a decline in digestive function, resulting in palpitation, dizziness, headache, fatigue and other phenomena.