L-Theanine for Fat Loss

Minimal research sheds light on L-theanine’s potential to suppress weight gain.

• Regulating fat accumulation. Theanine has been shown to suppress weight gain and fat accumulation in animals.

Overview

Theanine is an amino acid found in plants and fungi in a variety of forms, the most common of which is L-theanine. Its structural similarity to the neurotransmitters glutamine and glutamate seems to be responsible for a number of nootropic effects:

• Reducing stress and anxiety
• Promoting relaxation & sleep
• Improving focus

L-theanine has been growing in popularity since its discovery as one of the main components of green tea (Camilla sinensis).¹ Indeed, L-theanine is the main ingredient responsible for the feeling of calm focus frequently associated with tea consumption. Theanine has also been purported to stabilize blood pressure, boost immune function during exercise, and possibly even promote weight loss.²

How L-Theanine Might Help With Fat Loss

Regulating fat digestion and absorption

Although the precise mechanism is unknown, theanine has been reported to help manage weight in animals.⁴ Moreover, as one of the principal active ingredients in green tea, it’s possible that it is partially responsible for green tea’s fat loss bio-activities, including limiting digestion and absorption of fat, enhancing metabolism, and lowering levels of free fatty acids and glucose, both of which are linked to obesity.^{5 6}

L-Theanine Benefits & Uses for Fat Loss

Using theanine supplements for promoting weight loss is a relatively new development, and one that is currently only backed by a few animal studies. Having said that, theanine supplementation is popular for a number of uses that may help facilitate a healthy weight, namely: ⁷

• Enhancing mood, focus and overall cognitive function
• Reducing anxiety
• Making it easier to fall asleep and improving sleep quality
• Combating cardiovascular complications

Research

Animal Research

Animal research has suggests that theanine may be capable of suppressing weight gain and help with obesity.

Theanine (0.03% of diet) may suppress weight gain and fat accumulation

In this study, female mice were fed a variety of diets containing 2% green tea powder or 0.3% catechins, 0.05% caffeine, and 0.03% theanine (individually and in combination) for 16 weeks. Theanine (both separately and with the other compounds) was found to limit body weight increase and the amount of adipose tissue (stored fat) in the body, as well as reduce levels of triglycerides (TG) and fatty acids in the blood.

• The study concluded that “caffeine and theanine were responsible for the suppressive effect of green tea powder (GTP) on body weight increase and fat accumulation. Moreover, it was shown that catechins and caffeine were synergistic in anti-obesity activities.”⁸

Theanine-enriched green tea may have anti-obesity effects

In this study, mice were fed a normal diet, a high-fat diet (HFD), HFD with green tea (GT) containing high levels of theanine, or HFD with catechins. At the end of the investigation, the HFD with GT diet was shown to mitigate the fat accumulating consequences of obesity induced by the HFD. In other words, theanine-rich green tea had anti-obesity effects.

• The study concluded that “obese mice showed changes associated with abnormal lipid and energy metabolism, which were alleviated by GT intake, indicating the mechanism underlying the anti-obesity effects of GT.”⁹

Human Research

There are currently no clinical studies directly examining the impact of isolated theanine on fat loss. As a critical ingredient in green tea’s composition, however, theanine may plausibly be found to promote fat-burning activities in future studies. (See clinical research backing green tea as a fat burner).

Dosage for Fat Loss

• Research studies generally use from 200 – 400 mg of L-theanine
• Typical supplements come in 50 – 100 mg capsules, taken 1 – 4 times daily