Theanine

Also known as: L-Theanine

 

 

Safety Rating: 

LIKELY HARMFUL

  • None

NOT ENOUGH INFO 

  • Breastfeeding
  • Pregnancy
  • Children (exception age 8-12)
  • Elderly (65+)

POSSIBLY UNSAFE

  • None

POSSIBLY SAFE 

up to 400 mg daily

  • Children age 8-12: up to 6 weeks
  • General population: up to 8 weeks

LIKELY SAFE

  • None

 

For explanations of what these safety ratings mean, click here.

Potential Side effects

 

Headache 

Sleepiness

 

 

Overview

 

What is it? Theanine is an amino acid found in tea and some mushrooms. 

Why is it used? Theanine is often found in supplements that claim to reduce stress/anxiety or improve brain function.

What’s the harm? Theanine is LIKELY SAFE in quantities found in food and has been used with minimal side effects by healthy adults in some studies. However, there is NOT ENOUGH INFO available about use during pregnancy and breast-feeding, so it should be avoided in those cases.

 

 

Interactions with health conditions

 

Blood pressure: According to animal studies, Theanine might lower blood pressure, and this may be more severe if combined with blood pressure lowering medications. If blood pressure drops severely, that can cause or worsen dizziness. This is especially concerning for elderly patients, because dizziness could increase their risk of falling, possibly causing serious injuries like broken hips.


Low energy: Theanine may cause sleepiness.

 

 

Drug Interactions

 

Blood pressure medications: According to animal studies, Theanine might lower blood pressure. If blood pressure drops severely, that can cause or worsen dizziness. This is especially concerning for elderly patients, because dizziness could increase their risk of falling, possibly causing serious injuries like broken hips.


Stimulants: Theanine may reduce the stimulant effect of some drugs. Stimulant drugs are often used for ADHD and weight loss.

 

 

Interactions with herbs/supplements

 

Blood pressure: According to animal studies, Theanine might lower blood pressure, and this may be more severe if combined with other ingredients that lower blood pressure. If blood pressure drops severely, that can cause or worsen dizziness. This is especially concerning for elderly patients, because dizziness could increase their risk of falling, possibly causing serious injuries like broken hips.

Caffeine: Theanine can reduce the stimulant effect of caffeine.

 

 

Interactions with foods:

 

Caffeinated beverages such as coffee and tea may have a reduced stimulant effect when combined with Theanine.

 

 

Interactions with lab tests: None Known

 

References

  1. *Natural Medicines. (2019, March 11). L-Theanine [Monograph]. Natural Standard Professional Monograph. Retrieved from: https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=1053
     

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