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

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  • Product Code: DRB-00197
  • UPC Code: 753950001978
  • Package Quantity: 90 Veggie Caps
  • Dimensions: 4 x 2.1 x 2.1 in, 0.1 lbs (0.05 kg)
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Product Overview


  • Science-Based Nutrition
  • Dietary Supplement
  • Helps Promote Relaxation without Drowsiness
  • Helps Reduce Stress and Tension
  • Vegan

Suntheanine is the premier, patented form of the amino acid L-theanine. Suntheanine is the purest form of L-theanine on the market today. L-theanine is an amino acid derived from green tea that is responsible for the relaxation-inducing effect of tea consumption.

  • Helps promote a relaxed state without drowsiness.
  • Helps ease stress and everyday nervous tension.
  • Helps promotes a healthy mood and alertness.

Suggested Use

Suggested Adult Use: Take 1 capsule daily away from food, or as recommended by a nutritionally-informed physician.

Other Ingredients

Microcrystalline cellulose, modified cellulose (vegetarian capsule)

Non-GMO, gluten-free, vegan


Store in a cool dry place.

Supplement Facts
Serving Size: 1 capsule
Serving Per Container: 90 servings
  Amount Per Serving %Daily Value
Suntheanine L-theanine 150 mg
†Daily Value not established.
iHerb Customer Reviews


Posted by Reviewer1377782 on Jun 30, 2016

I have been suffering the sudden loss of my brother at the age of 69 years old - 2 years older than me, and my nerves have been shattered. I have been unable to cope with anything. Following the shock, my rheumatoid arthritis flared miserably and I was in severe pain for a few weeks. I would wake in the morning and find my heart beating faster than normal. I was not able to breath properly and my anxiety and fear levels were very high. I immediately started taking extra magnesium and G.R.Lanes 'Quiet life ' tablets - 2 in the morning before I got up. Also, before I got up I would take about 150 mg. GABA which slowed my heart rate to normal and I would take a capsule of Tulsi tea powder which gave me a feeling of centred calm. However, while this all brought me down to a near normal state, I still could not bring myself to go to the doctor let alone my usual yearly visit to the Rheumatology department at the hospital. I read about this product as I searched frenetically online for help or for someone else who has suffered in the same way and went to iherb to see if they stocked it and so I bought it. I found my hospital appointment was three days away instead of my usual June date, forgetting that they had changed it. I had a panic attack and planned to make an excuse not to go as my nerves were still extremely bad and I panicked at every opportunity that they chose. On the day of my hospital appointment, my order for suntheanine arrived EARLY - it wasn't due for another three days, so, I took 1 capsule about an hour before I my appointment. As we left home I started to panic but controlled it with breathing and thinking of my brother in Heaven enjoying himself and talking to our parents who have also gone to Heaven, then about half an hour later, as we got nearer the hospital, I realised that I was calm, with a non drowsy calm that I hadn't felt for many months. I felt so normal that I told the doctor about how I felt and what I took to get in this normal state. I got through this traumatic time easily and the feeling of non drugged calm released so much tension that I cried like it was in fashion. I have this each morning now and I am noticing I am able to cope 100% better without taking all those other natural calmers. AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ several million times.

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A great product for stress

Posted by Reviewer2585485 on Jun 24, 2016

I take this product for stress and it is very good. Highly recommended!

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Seems to lower appetite

Posted by 5539113384560379125 on Jun 09, 2016

I've used it for a while, and there were some interesting effects, but they were one-off. One thing that seems to persist is that I'm less hungry, when I take it.

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Pleasantly Surprised!

Posted by Sickness-ELIMINATOR on Jun 03, 2016

I started with 150mg at bedtime, and found it lowers my morning fasting blood sugar! I did not expect this, but discovered it while I was testing frequently. This may be due to the comments I see on the net that theanine can lower cortisol...which is considered a factor in some "dawn phenomenon" patients with insulin resistance/type II diabetes. I don't know if this is really the explanation, but it certainly lowered my morning fasting glucose readings by 30pts or more! During the course of this bottle which is a 90 ct size, our home has had a major stressor, and grief generator, and I have been very upset during this time. So last night I took 300mg instead of the usual 150mg. I slept more soundly, and awakened with a less "heavy heart"...which is what I call my anxiety grief reaction to the acute/temporary stress here. If I feel the return of this anxiety today, I'll take 150mg in the daytime, and another 300mg at bedtime. I am very pleased with this product for myself. But I do think people may vary in their responses. And I think perhaps a higher dose may work for those that are not satisfied with 150mg a day. . . . You can find other products I use on my Page!

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Helps with sleep

Posted by 5206100159286206775 on May 25, 2016

Theanine with Tryptophan helps with sleep on the occasional nights when I'm awake in the middle of the night.

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