L-Theanine

What is L-Theanine?

L-Theanine (Anxitane®, Composure®) is a nutritional supplement used to treat anxiety and environmental-induced stress in dogs and cats. It is an amino acid present in green tea and promotes relaxation without causing drowsiness. This supplement may be useful in situations such as grooming visits, thunderstorms, and travel.

The U.S. Food and Drug Administration (FDA) does not review non-drug health products (e.g., herbals, nutraceuticals, shampoos, and other supplements) for safety or effectiveness before they are sold to the public. Manufacturers of non-drug health products must ensure their products are safe and labeled accurately. The FDA requires that these non-pharmaceuticals contain a disclaimer that says, “This product is not intended to diagnose, treat, cure or prevent any disease.” Health Canada licenses “veterinary health products” after reviewing safety, efficacy, and manufacturing information provided by the manufacturer. These products are not tested by Health Canada.

Your veterinarian is the best source of information about the safety of non-drug health products in pets. Just because a product is natural does not mean it is safe. All medicines and medicinal plants are potentially toxic if used inappropriately or given at high doses. Supplements can also have side effects, like pharmaceuticals. Few supplements and herbs have been subjected to rigorous scientific trials to determine their efficacy. 

Although the information in this handout may be helpful, it may also be incomplete and may not represent the full range of effects the supplement could have on your pet.

How do I give my pet L-Theanine?

• L-Theanine comes in the form of chewable tablets, soft-chews, and liquid supplements.
• Chewable tablets and soft-chews are flavored. Liquid supplements are unflavored.
• L–Theanine can be given on a daily or as-needed basis.
• Follow your veterinarian’s directions and measure liquid forms of this supplement carefully.
• Shake liquid well before use.
• If you have difficulty getting your animal to take the supplement, ask your veterinarian or pharmacist for tips to reduce the stress of medication time for both you and your animal.

This fast-acting supplement should take effect within 1 hour and improvement in clinical signs should follow. 

What if I miss giving my pet the supplement?

If you miss a dose, give it as soon as you remember. However, if it is almost time for the next scheduled dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.  

Are there any potential side effects from L-Theanine?

There are no known side effects from L-Theanine. 

Drug sensitivities can develop over time with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment. 

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting supplement should stop working within several hours, although effects may be longer in pets with liver or kidney disease. 

Are there any risk factors for this supplement?

This supplement should NOT BE USED in:

• pets who are allergic or have had a previous reaction to it
• animals with severe phobias or separation anxiety
• animals with a known history of aggression

Are there any drug interactions I should be aware of?

There are no known drug interactions for L-Theanine. 

Certain medications may interact with L-Theanine and so it is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your dog is taking before starting any new treatment.

Is any monitoring needed with this supplement?

• At home, monitor for any side effects such as those noted above. If any side effects occur, stop using the supplement and contact your veterinarian. 
• Your veterinarian will let you know when they want to reassess your pet to ensure the medication is working and not causing side effects.

How do I store L-Theanine?

• Store chewable tablets and soft-chews in their original container at room temperature (20°C–25°C or 68°F–77°F).
• Store Anxitane® tablets in their original blister pack until used. 
• Keep this and all medication out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the supplement, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.