The Significance of Tyrosine Crystals in the Urine of Dogs and Cats

You should discuss tyrosine crystals with your vet.
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Tyrosine crystals in your pet's urine can be worrisome. However, once you understand what they are and what causes them, you've taken the first steps towards handling the situation. Getting a bit of knowledge on your side is a positive first step for your pet's health.

What are They?

Tyosine crystals are microscopic particles in the urine of your cat or dog. To a vet with a microscope, they look like tiny, needle-shaped crystals. They can vary in color from clear and colorless to brown. They are usually found in acidic urine, or urine with a pH of less than seven on the 14-point pH scale.


Tyrosine is an amino acid, and amino acids are the building blocks of proteins. In order for tyrosine crystals to form in your pet's urine, your pet has to have excess amino acids in her urine. The presence of amino acids in urine is called aminoaciduria. Your vet may also use the term "crystalluria," which specifically means the presence of crystals in the urine.

What Do They Mean?

Crystalluria in general can be an indication of uroliths (kidney stones). A kidney stone the same thing as these crystals, just larger. However, the presence of microscopic tyrosine crystals does not necessarily mean your pet has kidney stones, only that your pet could be predisposed to them. At the same time, tyrosine crystals (or any other amino acid-based crystal) can be a sign of liver problems. Keep in mind that some dogs and cats just produce tyrosine crystals as part of their individual physiology. Only a vet can tell if it's a cause for concern.

What to Do?

Your vet should control the course of your pet's treatment, since tyrosine crystals can mean anything from a non-issue to liver damage. Depending on the underlying cause, the first step is usually to change your pet's diet. If new food doesn't correct the problem, medications are prescribed to dissolve the stone. As a last resort, your veterinarian may use surgery to physically remove stones from your dog or cat. Many of these are the same treatments used in humans, so you know your pet will be in good hands.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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