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

L-theanine may help with sleep, stress, anxiety, and caffeine-related jitters, but it can also cause sleepiness and unusually vivid dreams. Supplement use should be considered after getting behavioral basics in place, and discussed with a healthcare professional. 1 2

• Sleep: A suggested range is 100–200 mg, taken 30–60 minutes before bed. 3 4
• Caffeine-related jitters: 200–400 mg is described as an effective dose; a lower 100–200 mg amount with coffee or tea is also mentioned. 5 6
• Other possible effects: It may modestly ease anxiety and stress, slightly improve attention and lower blood pressure, and support blood-vessel function and blood flow. 7 8
• Higher amounts: Up to 900 mg per day was described as generally safe, but this is a high dose and may cause substantial sleepiness. 9
• Dream-related caution: Theanine can make dreams vivid or intense. Avoid it if you sleepwalk or experience night terrors; consider leaving it out if vivid dreams disrupt your sleep. 10 11