Doctor's Best L-Theanine with Suntheanine 150mg 90 Veggie Caps

L-Theanine with Suntheanine® for Calm Focus & Stress Relief

Doctor's Best L-Theanine features Suntheanine® — the only pure L-isomer form of theanine, produced via a patented enzymatic process that mirrors how it naturally occurs in green tea. L-Theanine promotes a relaxed, calm mental state without causing drowsiness, making it ideal for stress relief, focus and supporting quality sleep.

Key Benefits

• Suntheanine® — clinically studied pure L-theanine, not a cheaper DL-theanine blend
• Promotes calm alertness — relaxed without sedation
• Supports healthy stress response and nervous system balance
• Can be combined with caffeine for focused energy without jitteriness

How to Use

Take 1–2 capsules once or twice daily, or as directed by a healthcare professional. Can be taken with or without caffeine. For sleep support, take 1–2 capsules 30 minutes before bed.

Frequently Asked Questions

What does L-theanine feel like?
Most people describe it as “calm but clear” — like the feeling of sitting quietly with a cup of green tea. No drowsiness, no sedation, just a gentle quieting of mental noise.

Can I take L-theanine with coffee?
Yes — L-theanine and caffeine are a well-known combination. Theanine smooths out caffeine’s jittery edge while preserving its focus and energy benefits.

What is the difference between Suntheanine® and generic L-theanine?
Suntheanine® is pure L-isomer theanine — the same form found naturally in green tea. Generic brands often use DL-theanine (a 50/50 mix with an inactive isomer). Suntheanine® is more effective per dose.

Is L-theanine safe for daily use?
Yes — it is well-tolerated for daily long-term use with no known dependency or withdrawal.