Why does tea make people alert?
First, we must clarify that tea refreshes because it contains caffeine, the substance that excites you. The higher the caffeine content, the more likely it is to stimulate you.
What determines the level of caffeine content?
The caffeine content in tea leaves depends on many factors, such as variety, growing conditions, picking season, picking standards, processing, etc.

The caffeine in tea leaves is relatively stable and does not decrease much during the fermentation process. Many people feel that green tea has higher caffeine because the tea polyphenols in green tea are not oxidized, leaving the caffeine in a free state; while after fermentation, tea polyphenols wrap around the caffeine, reducing irritation to the stomach, but the content does not decrease.
Key points for drinking tea at night:
About 3 minutes after the tea is brewed, most of the caffeine in the tea leaves has already dissolved into the tea water. At this point, the tea has a significant refreshing effect, making people alert. If you fear insomnia, do not drink the first infusion of tea, and especially avoid strong tea.

1. Drink lighter tea. 【Reduce caffeine】
2. Drink tea with a sweeter taste. 【More L-theanine, scientifically proven to be more beneficial for sleep than medicine, with no side effects】
3. Drink more fermented tea.
So how should you choose tea?
Many teas meet the above two requirements.
For example, dark tea 【best to choose Fu brick tea that has been stored for many years】;
For example, Pu-erh 【best to choose aged ancient tree Pu-erh】;
Also, white tea 【best to choose Shou Mei, stored for over three years for oxidation】, and the process does not involve enzyme deactivation, retaining more L-theanine, with a milder and sweeter taste.

Additionally, tolerance to caffeine varies based on habits and constitution. Some people drink tea all day without insomnia; others may experience palpitations, dizziness, or weakness (so-called "tea drunkenness") if they suddenly drink a large amount or on an empty stomach. As for caffeine, with increased frequency and dosage, one's tolerance can improve.