What can you tell me about l theanine and about recommended supplement’s

L-theanine may help with sleep, stress and anxiety, and caffeine-related jitters; the suggested amount depends on why you’re taking it.

• For sleep: 100–200 mg about 30–60 minutes before bed may help with the transition to sleep and sleep depth. Some people use 100–400 mg, but vivid dreams can make sleep more disruptive. 1 2
• For caffeine jitters: 200–400 mg may blunt caffeine-related jitteriness and anxiety. Theanine can also reduce alertness, so higher doses may feel overly sedating. 3
• Other reported effects: It may modestly ease anxiety and stress, slightly improve attention, lower blood pressure, and support blood-vessel function and blood flow. 4 5
• Safety and caution: Doses up to 900 mg per day were described as potentially safe, but that high an amount may cause uncomfortable sleepiness. Avoid it before bed if you have night terrors, sleepwalk, or are troubled by very vivid dreams; consider discussing supplementation with a physician. 6 7 8