L-Theanine for Dogs

Written by: Dr. Sarah Sims, DVM

Quick links: L-Theanine Dosage for Dogs – L-Theanine Side Effects in Dogs – L-Theanine Products for Dogs


Theanine for DogsIn the fast-paced, results-focused world we live in today, it is not all that surprising that numbers as high as 41% have been reported for the prevalence of excessive anxiety in dogs.  Specific types of anxiety disorders include:

  • generalized anxiety (a dog that is anxious, regardless of circumstances),
  • separation anxiety (a dog that is anxious to be apart from his owner),
  • and noise aversion (such as a thunderstorm or firework-induced anxiety),

just to name a few.

Even aggression, such as that toward:

  • dogs,
  • children,
  • or strangers,

is a type of anxiety disorder.

The cornerstone to treating any anxiety disorder is a form of “doggy therapy” called behavior modification, but most dogs also benefit from the help of supplements and medications that help alter the fear pathways in their brain chemistry as well.  One of the most effective supplements for this purpose is called L-Theanine.


L-Theanine History

Discovered as an amino acid relatively unique to green tea leaves in the 1940s, L-theanine became a staple in the Japanese diet in the 1960s for the purpose of promoting focused relaxation.  It holds “generally regarded as safe” status in the USA, and is a permitted for use in nearly every country that allows supplements to be distributed.

While there are approximately 20mg of L-theanine found naturally in green tea leaves, supplements use a synthetic version of the amino acid in amounts as high as 200mg in commercial products.  The most widely recognized brand of synthetic L-theanine is called Suntheanine.  Since the quality of ingredients can vary greatly from one brand of supplement to the other, Suntheanine is the only source of synthetic L-theanine I recommend.


L-Theanine Benefits

The exact mechanism L-theanine uses to exert its calming effects on the brain are still unknown, however, the neurotransmitter GABA appears to play a large role in its actions.  GABA is the main inhibitory neurotransmitter in the brain, meaning its job is to decrease reactivity and slow down message transit, both of which contribute to a decreased state of anxiety and arousal.  An even more compelling effect of L-theanine on the brain is an increase in alpha waves, the waves characteristic of a calm, focused mental state, such as those recorded during meditation exercises.  This unique brain waveform is not commonly seen in pets or people medicated with traditional anxiety medications such as Xanax or Klonopin, both of which cause drowsiness.  It is likely this characteristic that gives L-theanine users the unique feeling of being calm but not tired or dopey.


L-Theanine Side Effects in Dogs

Suntheanine side effects have not yet been reported officially in dogs and cats.  In humans, there have been reports of headaches, low blood pressure, and changes in thought patterns.  The only known risk of using theanine for dogs with anxiety is that it may not work.


L-Theanine Dosage for Dogs

Most human products only come in 100mg capsules/tablets, so I follow this general guideline in regards to L-theanine dosage for dogs:

  • < 10 lbs: use Anxitane-S as directed.  There is no human product small enough.
  • 10-20 lbs: 100 mg every 6 hours
  • 21-40 lbs: 200 mg every 6 hours
  • 41-60 lbs: 300 mg every 6 hours
  • 61-80 lbs: 400 mg every 6 hours
  • 81+ lbs: 500 mg every 6 hours


Where to Buy Suntheanine for Pets

Virbac makes a brand name product containing Suntheanine for dogs and cats called Anxitane.  It comes in a flavored tablet which many pets eat readily, and is available through your veterinarian or some online retailers. It comes in 2 different sizes and we included links to Amazon for easy shopping:

Anxitane-S for small dogs, and

Anxitane-M&L for medium and large dogs.

The labeled dose of Anxitane for dogs is 1 – 10 mg per pound. See calculator above!

The wide dosing range is a result of its high margin of safety and its variable effect from dog to dog.  You can also purchase

L-Theanine supplements meant for humans

over the counter.  Many chewable tablets contain xylitol, a sugar substitute that is toxic to dogs.  Stick to capsules of Suntheanine-branded products for assurance of safety and quality.

approved by veterinarian




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