Tryptophan for Dogs

Posted by Nicole Wanner, D.V.M. on

Tryptophan for Dogs

Managing a dog with anxiety can be challenging. We all want our furry friends to be happy and will do whatever we can to help. Tryptophan for dogs is a dietary supplement commonly recommended online for dog anxiety and other concerns.

But what is tryptophan, and what does the research say about its health benefits? In this article, we'll answer these questions, delve into symptoms and causes of anxiety in dogs, and more.

What Is L-Tryptophan for Dogs?

Tryptophan, specifically L-tryptophan, is an essential amino acid. In other words, this nutrient must be provided by your dog's diet. Without it, symptoms of tryptophan deficiency will develop.

Why is Tryptophan Essential?

This amino acid is a biological building block with many uses in your dog's body. For example, tryptophan plays a crucial role in producing serotonin and melatonin.

These compounds help regulate mood, sleep, appetite, and other functions.

How Do I Pronounce L-Tryptophan?

Tryptophan is pronounced 'TRIP-tuh-fan.'

tryptophan is an essential amino acid

Common Signs of Anxiety in Dogs

Anxiety in dogs is a common concern for which tryptophan supplements are advertised. Typically, anxious dogs are nervous, frightened by harmless stimuli, or prone to undesired behaviors.

Typical symptoms of anxiety in dogs include:

  • Destructive behavior (chewing, digging, etc.)
  • Excessive barking
  • Restlessness
  • Ears pulled back
  • Whining
  • Drooling
  • Excessive panting
  • Trembling
  • Aggression

Anxiety in dogs almost always has an underlying cause (1). If you notice these signs in your dog, consult your veterinarian to determine the best course of treatment.

What Causes Canine Anxiety

A wide variety of factors can trigger canine anxiety.

Examples of anxiety-inducing situations for dogs include:

  • Separation from owners
  • Changes in the environment (moving house, etc.)
  • Loud noises (thunderstorms, fireworks)
  • Upsetting or traumatic previous experience 

It's important to remember that each dog is unique, and what causes anxiety in one dog may not affect another.

anxiety in dogs

Benefits of L-Tryptophan for Dogs

Research on the benefits of tryptophan supplementation for dogs is limited to less than a handful of small studies. One study of eleven dogs found that tryptophan may reduce territorial aggression when combined with a low-protein diet (2). However, a larger analysis of 29 dogs found no effect (3).

Here's what we can say for sure: tryptophan supplements are beneficial for dogs suffering from a dietary deficiency. Federal regulations require complete dog foods to contain tryptophan, so most dogs receive a sufficient amount. If you feed a homemade diet, carefully calculate the nutrient content with your veterinarian to avoid tryptophan deficiency and other imbalances.

There is evidence that dogs of different breeds, sizes, and ages may process tryptophan differently (4). If you're concerned about tryptophan deficiency, reach out to your veterinarian. They'll carefully review your dog's symptoms and help you build an appropriate management plan.

Will L-Tryptophan Make My Dog Drowsy?

Tryptophan should not make your dog tired or sleepy. While L-tryptophan is involved in sleep as a precursor to melatonin, the so-called "turkey sleepiness myth" is not supported by science.

If your dog seems unusually tired after taking L-tryptophan, stop giving the supplement and consult your veterinarian.

dog sleeping with favorite toy

Precautions and Side Effects

As with any supplement, it's important to use L-tryptophan safely. Always consult with your vet before starting any new supplement regimen. L-tryptophan supplements could interact with certain medications and may not be suitable for dogs with certain health conditions.

For healthy dogs, side effects of L-tryptophan are generally mild but can include stomach upset and loss of appetite. Contact your veterinarian with any side effect concerns.

Dosing Information of Tryptophan for Dogs and Cats

The appropriate dose of L-tryptophan can vary depending on a dog's size, age, and overall health status. After discussing tryptophan supplements with your veterinarian, choose a product formulated specifically for dogs. Tryptophan is available in a variety of flavored chews, powders, and capsules, depending on your dog's preferences.

The concentration of tryptophan per serving will vary by brand and product type, so follow the manufacturer's dosing instructions closely. Choose a company that offers independent third-party testing to ensure your dog gets an accurate dose.


L-tryptophan is an essential amino acid and a popular dietary supplement for dogs. Tryptophan supplements are certainly beneficial for dogs with a nutrient deficiency. However, limited research means that L-tryptophan's effectiveness for concerns like anxiety is unknown.

In the end, each dog is unique. The best approach for managing anxiety will likely include traditional medication, environmental changes, and behavior training. As their name implies, supplements are "something extra." They can support our pets' health but shouldn't be used alone.

Always consult your veterinarian before starting any new supplement regimen. Together, you can build a new routine to help your dog live their best, happiest life.



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  • This is such a great article. I have an anxious pup and will take this advice to heart.

    Catherine Behan on

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Dr. Nicole Wanner graduated from the University of Minnesota College of Veterinary Medicine in 2018. Currently, she is an academic research veterinarian studying CBD and DNA. Her research has been published in trusted international research journals. Dr. Wanner is passionate about pet wellness and has professional interests in genetics, behavior, and healthy aging. In her free time, she enjoys hiking and reading sci-fi novels. She shares her home with her husband Evan and their two mischievous rescue cats, Sylvie and Nemo.
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