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Spirulina for Dogs: Benefits and Uses

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Plant-based foods have had a serious boom in popularity in recent years. According to a 2021 report from the Good Food Institute, grocery sales of plant-based foods grew by 27 percent in the previous year. And the plant-based foods trend has trickled down to pets as well, with major pet food brands now offering plant-based pet food options that include protein sourced from brown rice, barley, chickpeas, peas, potatoes, oats, lentils, and more. 

Spirulina is another plant-based protein source that is growing in popularity. It’s actually been sold as a supplement and used by humans for lowering bad cholesterol, decreasing inflammation, reducing blood pressure, improving allergy symptoms, and more since the late 1970s, according to the U.S. National Library of Medicine. And now, an interest in spirulina for dogs has sparked.

But is spirulina good for dogs? Let’s take a closer look at the benefits of spirulina and how you can safely implement this vegan protein into your pup’s diet.

What Is Spirulina?

Spirulina is actually just blue-green algae, also known as cyanobacteria (1). 

“They are, and have been for centuries, used as both food sources and as supplements (2),” says Dr. Emily Luisana, veterinarian and Clinical Nutrition Fellow at BluePearl Veterinary Specialty Hospital of the Carolinas. 

Spirulina is loaded with macronutrients, including protein, fat, carbohydrates, and several vitamins and minerals. According to the USDA, one single tablespoon (7 grams) of dried spirulina powder contains (3):

  • Calories: 20
  • Protein: 4 grams
  • Fat: .54 grams

Spirulina is also noted for being rich in vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), copper, iron, magnesium, potassium, and manganese.

Can Dogs Have Spirulina? 

Yes, spirulina can be safe to give your dog if you purchase it from a reputable manufacturer and use it according to the label. The Food & Drug Administration has listed uncontaminated spirulina extract as GRAS (generally recognized as safe).

However, that doesn’t mean it’s totally risk-free.

“Risks related to contamination and/or drug interactions are real concerns,” Luisana says. “There are limited studies in dogs, however, I am not aware of any that have shown adverse reactions, unless related to contamination.” (More on that contamination risk to come.)

Is Spirulina Good for Dogs?

In humans, spirulina has been studied as an immune system stimulator, antihistamine, antioxidant, and pain reliever (4, 5, 6). It has also been shown to reduce high cholesterol and hypertension (high cholesterol) (7, 8).

Animal studies are lacking overall, but have shown some potential benefits in immune system function, as an anti-inflammatory and anti-allergen, and as a protective cancer therapy for chemotherapy and radiation (9, 10, 11, 12).

How to Give Spirulina for Dogs

spirulina treats

Spirulina comes in many forms, including powders, tablets, capsules, and mixed with other ingredients as a supplement or treat. According to Luisana, spirulina is found in many “immune support” products. 

But exact safe dosing has yet to be determined for dogs.

“As we do not know the safest, effective dose in dogs, we have to extrapolate from the limited human and canine studies,” Luisana says. “If pet parents are interested in trialing this supplement, I recommend discussing the pros/cons with their veterinarian to see if this supplement fits with their pet’s health plan.”

For humans, doses up to 19 grams per day have been used safely for up to two months, and lower doses of 10 grams per day have been used safely for up to six months (1).

Spirulina for Dogs Side Effects

Unfortunately, blue-green algae can be contaminated with harmful algae (and/or cyanotoxins) (13), as well as heavy metals during growing, harvesting, or processing, Luisana notes.

And toxicity has also been reported in some blue-green algae supplements (14).

Spirulina supplements could also cause issues with some medications your dog may be taking.

“Spirulina is an inhibitor of certain cytochrome p450 enzymes (15), which are involved in metabolism of many medications and other supplements, which is another reason its use should always be discussed with your veterinarian,” Luisana adds.

And if your dog has any autoimmune issues, you should be extra cautious.

“And although spirulina may have immune-stimulating effects, special concern should also be given to pets with autoimmune disease and/or who are on immunomodulating medications (for example, many medications used for allergies) (16),” Luisana says. 

How to Choose Spirulina for Dogs

spirulina powder

Spirulina for dogs is available in many different forms ranging from supplements to treats and chews.

When Luisana makes recommendations for supplements or treats, she tells her clients to: 

  • Choose a reputable brand that uses third-party verification 
  • Read the label carefully for concentration 
  • Look for and consider the implications of any additional ingredients, both active and inactive 

“I prefer NASC (National Animal Supplement Council) certification for any supplements I recommend,” she says. “I also encourage consumers to not be afraid of calling the manufacturer and ask for more information, such as where they source their products, how they screen for toxins, etc.”

And of course, you can give your vet a call to make sure he or she supports your dog starting a spirulina supplement.

Spirulina dog treats may be an ideal starting place if you’re interested in supplementing your dog’s diet with this ingredient. These treats usually have a lower concentration of spirulina and manufacturers bake in amounts that are safe for dogs. Just remember to follow label instructions to avoid feeding your dog too many spirulina dog treats. And if you have any concerns, consult your veterinarian.