9 L-Theanine Benefits That Go Far Beyond Anxiety

Feeling stressed? Do you think you’ll about to get sick? A cup of green tea may be what you need.

Green tea has the most antioxidants of all the tea varieties and a number of/ other health benefits too.

Many of those benefits come from L-Theanine, an amino acid found in black and green tea. L-Theanine benefits include reducing anxiety, along with improving a number of other problems.

Here are a few other ways L-Theanine can help you.

L-Theanine for Weight Loss


Numerous studies have linked L-Theanine to weight loss. One study specifically looked at the various compounds in green tea to see what effect they would have on weight loss.

The study involved a group of mice that were given green tea, caffeine, catechins or theanine for a period of 16 weeks. The mice showed a drop in body weight at the end of the trial period.

Additionally, mice given green tea, catechins or theanine had a decrease in their concentrations of triglycerides and non-esterified fatty acids. The study concluded that caffeine and theanine in green tea had a suppressive effect on increasing body weight and fat accumulation.

That sounds great for the mice, but what about people? Studies in humans have shown a similar result.

One study gave a group of men capsules containing green tea extract. The extract contained L-Theanine, but not caffeine. Half of the men took the green tea pills, the other half took a placebo.

Men taking the green tea extract pills saw a reduction in body fat of 1.63% over the course of the study.

L-Theanine to Boost Concentration

Another L-Theanine benefit is boosting your ability to focus. It’s a water soluble amino acid, which means it passes through the blood-brain barrier within half an hour.

The L-Theanine’s effectiveness as a concentration and focus booster are increased when it’s taken in combination with caffeine. In one study, a group of young adults reported improved accuracy when task-switching as well as higher levels of alertness after taking 97 mg L-theanine and 40 mg caffeine.

A similar study involved 16 volunteers. The study participants were either given 100 mg of L-Theanine, 50 mg of caffeine, a combination of the two or a placebo for four days.

The participants who took both L-Theanine and caffeine demonstrated the greatest amount of improvement in behavior and performance at the end of the study.

L-Theanine to Lower Blood Pressure

About 1/3 of adults in the US have high blood pressure, which is a major problem. Most recently, hypertension (or high blood pressure) was shown to be a risk factor for developing Alzheimer’s disease.

L-Theanine is very effective at lowering blood pressure that it is often recommended that certain people do not take it or that they avoid drinking green tea. If you have a history of low blood pressure, L-Theanine can make the issue worse.

One study involving L-Theanine and caffeine examined the effects the two ingredients had on the blood pressure levels of people in high-stress situations. Some of the adults in the study had higher increases in blood pressure in response to stress than others.

The participants in the high response group had the best results when taking L-Theanine to reduce blood pressure spikes.

The researchers concluded that L-Theanine “significantly inhibited the blood-pressure increases” in that group, much more than caffeine or the placebo.

L-Theanine to Minimize Stress