---
product_id: 1864778
title: "Doctor's Best L-Theanine Contains Suntheanine, Helps Reduce Stress & Sleep, Non-GMO, Gluten Free, Vegan, 150 mg (DRB-00197), 90 Count"
brand: "doctor's best"
price: "₩63265"
currency: KRW
in_stock: true
reviews_count: 8
category: "Doctor's Best"
url: https://www.desertcart.kr/products/1864778-doctors-best-l-theanine-contains-suntheanine-helps-reduce-stress-sleep
store_origin: KR
region: South Korea
---

# Supports focus & alpha brain waves Non-GMO, Vegan & Gluten-Free 150 mg Suntheanine L-Theanine Doctor's Best L-Theanine Contains Suntheanine, Helps Reduce Stress & Sleep, Non-GMO, Gluten Free, Vegan, 150 mg (DRB-00197), 90 Count

**Brand:** doctor's best
**Price:** ₩63265
**Availability:** ✅ In Stock

## Summary

> 🧘‍♂️ Unlock calm focus and stress-free productivity—naturally.

## Quick Answers

- **What is this?** Doctor's Best L-Theanine Contains Suntheanine, Helps Reduce Stress & Sleep, Non-GMO, Gluten Free, Vegan, 150 mg (DRB-00197), 90 Count by doctor's best
- **How much does it cost?** ₩63265 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.kr](https://www.desertcart.kr/products/1864778-doctors-best-l-theanine-contains-suntheanine-helps-reduce-stress-sleep)

## Best For

- doctor's best enthusiasts

## Why This Product

- Trusted doctor's best brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Calm Focus, No Jitters:** Experience smooth mental clarity without the caffeine crash or drowsiness.
- • **Safe Nighttime Support:** Non-hormonal aid that promotes restful sleep without morning grogginess.
- • **Clean & Conscious Formula:** Non-GMO, vegan, and gluten-free—because your wellness routine deserves purity.
- • **Patented Suntheanine Power:** 150 mg of clinically studied L-Theanine for proven relaxation and cognitive support.
- • **Stress Relief Meets Productivity:** Stay calm under pressure while enhancing memory, attention, and focus.

## Overview

Doctor's Best L-Theanine delivers 150 mg of patented Suntheanine, a natural amino acid derived from green tea, designed to promote relaxation, reduce stress, and enhance cognitive focus without causing drowsiness. This non-GMO, vegan, and gluten-free supplement supports alpha brain wave activity for improved mental clarity and restful sleep, making it an ideal daily aid for busy professionals seeking balanced calm and productivity.

## Description

At Doctor’s Best, we understand that stress can be an unwelcome guest. That is why our specialized formula features a pure form of L-theanine that is renowned for promoting relaxation, managing stress, and sharpening focus for a more balanced state of mind.*

Review: Very good NON-hormonal OTC supplement that promotes relaxation at bedtime. - I find this particular formulation of L-Theanine to be a very good adjunct to help me fall asleep and stay asleep. This formula by the Doctor's Best brand has "Suntheanine," which is a patented form of the amino acid L-Theanine known to promote relaxation. I've taken this formula steadily for about a year at bedtime with only good results as part of an overall sleep hygiene routine that also includes listening to a Calm sleep story on the app in my phone, next to my bed. Also why I like this particular formulation is that it has just 150 mg of the Suntheanine/L-theanine in it, which is less than most other formulas on the market. IMO, less of something often translates to "more." I don't know how long it stays in the system, but probably not for very long, because I wake up normally, with no leftover drowsiness. Another reason why I like this supplement is because it's NON-hormonal. Some folks use melatonin to promote sleep, but I've always avoided that, since melatonin is a hormone, and from what I understand, it's not meant to be used long-term. For me, this has performed as a safe and effective over-the-counter sleep aid. As of December 2025, it was still reasonably priced.
Review: Smooth focus without jitters - This supplement really helps with calm focus. I take it in the morning with coffee and it removes any nervous edge from caffeine. Clean product, no aftertaste, works exactly as expected.

## Features

- DOCTOR’S BEST L-THEANINE CONTAINS SUNTHEANINE: a patented form of the amino acid L-theanine. The amino acid L-theanine, that can be found in green tea, is the ingredient that gives tea drinking its calming effects
- RELAXATION AND FOCUS SUPPORT: L-Theanine supports relaxation and a sense of calm without causing drowsiness or loss of focus. This amino acid found naturally in tea helps support healthy stress response, focus and memory
- COGNITIVE ENHANCEMENT: amino acid found in tea that is considered a natural cognitive enhancer, improving memory, focus, and attention span by promoting a calming effect while maintaining alertness
- FOCUS & MENTAL CLARITY: helps to improve alpha brain wave activity, supporting focus, attention, and cognitive performance. Ideal for staying calm under pressure at work or at home
- NATURALLY CALMING: calm and stay sharp with help from 150 mg of natural L-theanine; has been shown to help with relaxation and stress relief without making you sleepy. It helps you stay calm and mentally balanced all day

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN  | B001OXTGVG |
| Best Sellers Rank | #9,988 in Health & Household ( See Top 100 in Health & Household ) #1,078 in Sales & Deals |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,442) |
| Date First Available  | September 1, 2009 |
| Department  | Health and Beauty>Health and Wellness |
| Is Discontinued By Manufacturer  | No |
| Item model number  | DRB-00197 |
| Manufacturer  | Doctor's Best |
| Product Dimensions  | 2.13 x 2.13 x 3.69 inches; 2.12 ounces |

## Product Details

- **Age Range (Description):** Adult
- **Brand:** Doctor's BEST
- **Diet Type:** Gluten Free
- **Flavor:** Unflavored
- **Item Form:** Capsule
- **Item Weight:** 0.06 Kilograms
- **Item dimensions L x W x H:** 2.13 x 2.13 x 3.69 inches
- **Primary Supplement Type:** multivitamin
- **Product Benefits:** Relaxation
- **Unit Count:** 90 Count

## Images

![Doctor's Best L-Theanine Contains Suntheanine, Helps Reduce Stress & Sleep, Non-GMO, Gluten Free, Vegan, 150 mg (DRB-00197), 90 Count - Image 1](https://m.media-amazon.com/images/I/719zn9vom2L.jpg)

## Questions & Answers

**Q: How do you choose between their Suntheanine and their 5-HTP? Both seem to do the same thing.**
A: 5-HTP is the tryptophan-based intermediate to serotonin which most antidepressants work to increase or support.
It's more specifically targets serotonin, needed for a balanced mood.

Suntheanine, a patented and advanced form of L-Theanine, has a broader range of psychotherapeutic and neuro- cognitive benefits than does 5-HTP.

It works as an anti-anxiety from multiple paths. 1) It supports the levels of gaba to calm the brain 2)It blocks glutamate receptors in the brain from receiving an excitatory neurotrans-mitter 3) It induces Alpha Waves in the brain.

Additionally, as a small molecule powerful antioxidant, it crosses the blood brain barrier to reach neurons directly where it fight oxidation in them. 

This gives it the ability to fight or offer benefit against a wide range of age-related neuro-cognitive conditions such as memory loss, learning impairments, attention deficits, dementia, Alzheimer's etc.

**Q: Has anyone taken Suntheanine by opening the capsules and adding to liquid?  If so, how is the taste?**
A: My daughter, after first asking the doctor if it was safe, decided to try it with her Autistic child.  Since she can't swallow pills, my daughter opens the capsule and places it into applesauce or a similar food.   It still seems effective and my grandchild didn't seem to mind or notice any bad taste.  So, I assume if it can be placed in food, it should be fine to also place it in a liquid.  I hope this has helped you with your questions.

**Q: I see some theanine comes from China. I would prefer one produced in the USA. Does any ingrediant in this come from China?**
A: What is the country of origin for Doctor's Best products?Doctor's Best products are quality tested and manufactured in the United States using highly qualified cGMP manufacturers and raw material ingredients. Doctor's Best sources raw materials from around the world and ingredients are subject to the intense testing and verification regardless of geography of origin.- See more at: http://www.drbvitamins.com/products/suntheanine-l-theanine-150mg/drb-00197#sthash.wAlbJQD6.dpuf

**Q: Does this contain caffiene?**
A: It doesn't state anywhere on the bottle that it contains caffeine. I'm not sure, you will have to investigate further.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Very good NON-hormonal OTC supplement that promotes relaxation at bedtime.
*by M***4 on December 28, 2025*

I find this particular formulation of L-Theanine to be a very good adjunct to help me fall asleep and stay asleep. This formula by the Doctor's Best brand has "Suntheanine," which is a patented form of the amino acid L-Theanine known to promote relaxation. I've taken this formula steadily for about a year at bedtime with only good results as part of an overall sleep hygiene routine that also includes listening to a Calm sleep story on the app in my phone, next to my bed. Also why I like this particular formulation is that it has just 150 mg of the Suntheanine/L-theanine in it, which is less than most other formulas on the market. IMO, less of something often translates to "more." I don't know how long it stays in the system, but probably not for very long, because I wake up normally, with no leftover drowsiness. Another reason why I like this supplement is because it's NON-hormonal. Some folks use melatonin to promote sleep, but I've always avoided that, since melatonin is a hormone, and from what I understand, it's not meant to be used long-term. For me, this has performed as a safe and effective over-the-counter sleep aid. As of December 2025, it was still reasonably priced.

### ⭐⭐⭐⭐⭐ Smooth focus without jitters
*by K***V on September 18, 2025*

This supplement really helps with calm focus. I take it in the morning with coffee and it removes any nervous edge from caffeine. Clean product, no aftertaste, works exactly as expected.

### ⭐⭐⭐⭐⭐ It REALLY works GREAT!!
*by R***L on October 23, 2025*

This works really great for anxiety, calms me right down when I need it. I don't use it often but it sure is good to have it when I need it. It also helps me after a particularly long hard day at work when I'm having a lot of pain because it just relaxes me. I'm very glad it's not a prescription item. Thank you for having it Amazon!

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*Product available on Desertcart South Korea*
*Store origin: KR*
*Last updated: 2026-01-27*