L-Theanine: A Potential Relaxation Ingredient For Pets

By Julie Thibeau | March 1, 2003

An ingredient that has shown positive results when it comes to relaxing humans may have the same potential in pets.

The high pressure society we live in today has caused many consumers to seek alternative means for reducing their anxiety and stress. However, humans are not the only ones feeling the pressures of daily life as companion animals have their own set of issues to contend with as well. An ingredient ready to fill that niche is L-Theanine, which is an amino acid found in green tea that is noted for many health benefits, including relaxation.

A Little History

First introduced centuries ago in Southeast Asia, tea has become the most widely consumed beverage worldwide aside from water, and it is cultivated in more than 30 different countries. Tea leaves also happen to be a natural source of L-Theanine, however, only 1-2 % of the dry weight of tea leaves consists of L-Theanine. As a result, it is very time consuming and expensive to extract L-Theanine from tea leaves, and impossible to yield a 100% purity naturally. One company that has gotten over this hurdle is Taiyo Kagaku Co., Ltd., Yokkaichi, Japan, which has developed a patented enzymatic technology to synthesize 100% pure L-Theanine (Suntheanine®) that is structurally identical to the L-Theanine compound naturally found in tea.

L-Theanine was first discovered in tea leaves in 1950 and was given food additive approval by the Japanese Ministry of Health and Welfare since 1964. It has also been extensively researched and documented with over 45 different studies currently available. Most areas of research include cancer adjuvant therapy, reducing stress and anxiety, promoting relaxation and improving learning and concentration.

How it Works

Taiyo's Suntheanine is absorbed through the brush-border membrane in the large intestine and transported directly to the brain where it stimulates the generation of alpha brain waves. The brain transmits four different categories of brain waves, which are determined by frequency. These include gamma, theta, alpha and beta waves. Gamma waves are present during sound sleep; theta waves indicate dozing or sleeping; beta waves are present during an awake, excited state and alpha waves signify an awake, relaxed state. Because Suntheanine promotes alpha wave generation in the brain, an awake, alert and relaxed physical and mental condition is achieved. Dosage of Suntheanine is effective at 50-200 mg and its effects are exhibited within 30-40 minutes of consumption.

To prove this, a volunteer test was performed on 50 female subjects (18-22 years old) to investigate the effects of Suntheanine on brain wave activity. The women were divided into two groups: a high-anxiety group and a low-anxiety group. Each volunteer was either given 50 mg Suntheanine or 200 mg Suntheanine, once a week for a two month period. Brain waves were measured for 60 minutes after the administration of Suntheanine. The results showed that within 30 minutes of consumption of Suntheanine, there was significant generation of alpha waves in the occipital and parietal regions of the brain but no observable increase in theta waves. What this meant was that Suntheanine was able to promote a feeling of relaxation without causing drowsiness.

Safety & Claims

LD50, a classification of acute ingestion toxicity, determined Suntheanine to be greater than 5,000 mg/kg, causing no "significant or unreasonable risk of illness or injury." In addition, Suntheanine has no known drug interactions, side effects or any limit of duration of administration. As opposed to some of the other relaxation promoting ingredients on the market, Suntheanine promotes relaxation safely, without causing drowsiness or impairing cognitive or motor function.

In terms of Structure/Function claims, several have been approved by the Food and Drug Administration (FDA), including "Reduces stress," "Promotes relaxation without drowsiness," "Eases nervousness due to common every day overwork and fatigue" and "Reduces nervous irritability."

Patents & Research

Suntheanine has been awarded several manufacturing and use patents for quitting smoking, inhibiting anxiety, reducing PMS symptoms, improving the flavor of beverages and food, ameliorating attention deficit/hyperactivity disorder and improving the palatability of pet food. Most recently, however, U.S. patent 6,297,280 BI was awarded to Taiyo for suppressing the behavior problems of pets. Specifically the patent includes a, "Composition for suppressing behavior problems of pets, comprising L-Theanine, and optionally one or more compounds selected from the group con­sisting of highly unsaturated fatty acids and cho­lines; and a method of suppressing be­havior problems of pets, comprising ad­ministering the a­bove composition to a pet having behavior problems. The composition can be effectively used for suppressing various behavior problems associated with the pet."

Some of the behavior problems often exhibited by dogs, cats and other pets include destruction, attack, inappropriate elimination, excessive barking, scratching, loss of interrelation, abnormal vocalizing, aberrant motor behavior, reduced blood pressure and shivering.

To assess the effectiveness of Suntheanine on pets a study was conducted on nine cats. These cats, which were castrated or subjected to contraception, were exhibiting behavior problems of abnormal urine marking. Over a one week period, each cat was given a varying dose of Suntheanine daily and it was found that this negative behavior was suppressed.

In another study, nine indoor dogs exhibiting aggressive behavior such as abnormal barking and destruction of furniture were given varying doses of Suntheanine daily for one week. At the end of the study, it was determined that the aggressive behavior of these dogs was successfully suppressed with the use of Suntheanine.


Right now there are some products containing Suntheanine on the market, especially for dogs and cats. The products are available in two forms, including tablets and capsules. Generally the capsules are separated and the contents are added directly to the pet food or water at the time of feeding. However, Suntheanine is also suitable for mineral pre-mix formulations, vitamin pre-mixes, dry food, bones and treats among other applications.NW

About the author:
Julie Thibeau is the marketing director and senior research associate for NutriScience Innovations, Fairfield, CT, which is the exclusive distributor for Taiyo Kagaku's Suntheanine L-Theanine product. She can be reached at 203-334-3535; E-mail: julie@nutriscienceusa.com; Website: www.l-theanine.com; www.nutriscienceusa.com.

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