Spirulina for Dog Food Allergies? (A 2021 Research Paper Review)

On May 28th 2021 a brand-spanking-new research paper was published looking at the influence that dietary Spirulina has on the immune system of dogs – and social media has gone a bit nuts.

Headlines that covered the paper stated:

“-New Study- shows that adding Spirulina to your pet’s diet can help prevent or relieve food intolerances (aka food allergies)”


So let’s break down the study. You can also find the link to the study here if you want to read along!

The Study Goal:

The first thing that you need to understand about this particular study is that they were not actually looking at the effects of Spirulina on allergies in dogs directly. Aka – they did not give Spirulina to dogs with food allergies or intolerances and test to see if Spirulina supplementation helped relieve symptoms.

“The aim of this study was to evaluate the immunomodulatory effect of dietary supplementation with Spirulina in dogs.”

Satyaraj 2021

In particular this study evaluated the influence of Spirulina on the immune system of a group of dogs after they underwent an immunostimulatory event (rabies vaccination).

Research Study Set-Up:

Basically what they did is take a group of thirty dogs, and they vaccinated all the dogs with a three-year rabies vaccination (Merial IMRAB 3) – then after the vaccination, they divided them into a “control group” and a “test group”, with fifteen dogs in each group.

The control group was placed on a kibbled diet with the general composition of 26% protein, 42% fat, and 32% carbohydrates on a caloric basis. The test group was placed on the control diet with the addition of 0.2% Spirulina.

In increments of 4 weeks dogs were tested via blood and stools looking at different immune related compounds such as:

  • A Rapid Fluorescent Focus Inhibition Test (RFFIT) was used to measure serum rabies virus neutralizing antibodies.
  • Secretory IgA (sIgA) levels in fecal samples
  • C-reactive protein (CRP)

At the end of the study (week 42) a “stress test” was done to evaluate the gastrointestinal tract microbiome stability. Or simply put – how likely a stressful situation can cause loose stools in dogs. To do this dogs were motivated to do intense exercise, and samples were taken pre/post exercise to look at microbiome changes.

Blood chemistry (performed beginning/end of trial) and fecal scoring (recorded daily) on all dogs within the study.

The Results:

Overall both dog test groups were healthy at the end of the trial period – no significant difference was seen in fecal scoring, blood chemistry, or weight between diet trial groups. There was also no significant difference in C-Reactive Proteins seen between trial groups.

The main differences were seen in three categories: immune response to the rabies vaccination, IgA, and the gut microbiome stability.

  1. Spirulina supplementation caused a significantly increased antibody response to rabies vaccination.
  2. The addition of Spirulina to the diet caused a significant increase to fecal IgA levels from weeks 9 to 42.
  3. Dogs fed a diet supplemented with Spirulina had increased microbiome stability

Spirulina increased fecal IgA levels after just 9 weeks of feeding, and this effect was maintained throughout the study. Gut microbiota maintained enhanced stability following a challenging exercise in the Spirulina fed dogs as compared to the control group.

Systemic immune responsiveness was found to be fortified with Spirulina feeding leading to a faster and stronger induction of rabies vaccine titer. Together these results suggest that Spirulina fed dogs have a healthier and more robust immune system.

Satyaraj 2021
Dosage of Spirulina used in the study was 0.2%. This is around 1.5 to 2g for a 50 lb dog (about 1/2 tsp Spirulina), or 66-88mg/kg.

Supplement Used in Study: Arthrospira platensis, Cyanotech Corporation, Kailua-Kona, Hawaii, USA

Implications Spirulina Supplementation for Dogs

So as you can probably tell – the results of the study did not actually really prove anything about allergies, but they did show some pretty amazing results in regards to how Spirulina affects our pet’s immune system.

But there are some further implications that we can make by extrapolating this data while looking at results that have been seen in other species. This is where we get into that part about food allergies and intolerances.

Food Allergies and Spirulina in Mice

A study cited (Nemoto-Kawamura 2004) within the research paper’s discussion looked at the IgA response when food-allergic mice, and was used in order to propose further uses of Spirulina as a nutraceutical for dogs with allergies.

“The authors of this mouse study proposed that phycocyanin, extracted from Spirulina platanis, may reduce allergic inflammation by suppressing antigen specific IgE and augmenting intestinal IgA production.

The production of antigen specific sIgA from IgA-secreting cells in Peyer’s patches, and accompanying higher fecal sIgA levels, has been suggested to be a mechanism for the development of food tolerance.

Therefore, by supporting intestinal immune function, Spirulina, may not only help reduce opportunistic infections but may also help prevent food intolerance. In our current study, fecal sIgA levels were increased after just 2 months of feeding Spirulina and the positive enhancement was maintained to the end of the 42-week study.”

Satyaraj 2021

So let me break down a couple of key factors within this study, so you can understand some of the implications it has to our dog study.

First thing you need to know is that Phycocyanin is an active component within Spirulina – and composes about 10% of Spirulina (aka every 1000mg contains about 100g of phycocyanin).

Second, researchers found that phycocyanin most likely works in two ways to help mice with food allergies:

“amplification of IgA production in the mucosal immunity to defend against the invasion of allergens, and suppression of IgE and IgGl production in the systemic immunity to minimize excessive responses to allergens.”

Nemoto-Kawamura 2004

In layman’s terms – phycocyanin works to defend against invasion of allergens and minimize excessive responses to allergens.

Dosing used in this study was 57.5mg/kg Phycocyanin.

So basically this study did find that Phycocyanin at a certain dose has a significant effect against allergic response, however…

The dosage of Phycocyanin used within this study was 57.5mg/kg per day for the mice. If we were going to convert this to unpurified Spirulina we would be looking at about 575mg/kg per day, which is well above the 60-80mg/kg described in the current 2021 study. With this amount, we are looking at about 4-5 tsp of Spirulina for a 50 lb dog.

So though we saw an IgA response that was more robust in response to vaccination, it’s hard to say if the same response would be seen in response to an allergen at the current dosing. Further research is needed in order to draw this conclusion. We also need further research to evaluate the safety of Spirulina given at higher doses, as there are some reports of gastrointestinal upset when dogs are given large amounts.

My Thoughts: Not proven, but a possibility.

Though it is possible that Spirulina may have a mechanism by which to assist with food allergy response, further research would need to be done in this area to truly be able to make this claim. 

We do not know if Spirulina can help with Food Allergies (or other chronic enteropathies/gastrointestinal conditions) but at a low dose as used within this study, it would probably not cause harm. Though I would still, as always, discuss any additional supplements with your veterinarian prior just in case there is another reason why it might not be appropriate for your dog.

Another point I do want to mention in regards to the safety of spirulina for dogs – is that just like with most supplements, there are good brands and not-so-good ones. And we do have concerns with Spirulina being contaminated with something called hepatotoxic microcystins (MCs) – which can cause liver disease in dogs (Bautista 2015). A study published back in 2008 actually found 94% of Spirulina supplements on the market in China were contaminated with MCs (Jiang 2008). Thus asking companies for a certificate of analysis that includes testing for Mcs is extremely important.

What are your thoughts? Would you recommend giving this supplement for allergies? What about in conjunction with a rabies vaccination (or other immuno-stimulatory/suppressive events)?


Satyaraj E, Reynolds A, Engler R, Labuda J, Sun P. Supplementation of Diets With Spirulina Influences Immune and Gut Function in Dogs. Front Nutr. 2021 May 28;8:667072. doi: 10.3389/fnut.2021.667072. PMID: 34124121; PMCID: PMC8192834.

Nemoto-Kawamura C, Hirahashi T, Nagai T, Yamada H, Katoh T, Hayashi O. Phycocyanin enhances secretary IgA antibody response and suppresses allergic IgE antibody response in mice immunized with antigen-entrapped biodegradable microparticles. J Nutr Sci Vitaminol (Tokyo). 2004 Apr;50(2):129-36. doi: 10.3177/jnsv.50.129. PMID: 15242017.

Bautista AC, Moore CE, Lin Y, Cline MG, Benitah N, Puschner B. Hepatopathy following consumption of a commercially available blue-green algae dietary supplement in a dog. BMC Vet Res. 2015;11:136. Published 2015 Jun 19. doi:10.1186/s12917-015-0453-2

Jiang Y, Xie P, Chen J, Liang G. Detection of the hepatotoxic microcystins in 36 kinds of cyanobacteria Spirulina food products in China. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2008 Jul;25(7):885-94. doi: 10.1080/02652030701822045. PMID: 18569007.

About the Author: Nikki is a Registered Veterinary Technician (Veterinary Nurse) and Dog Mom with over a decade of experience with dogs and cats. Since graduation from college (BS Biology, Dip. Animal Nutrition, AS Animal Science) she has adopted two mixed breed dogs – Ranger and Ash, and has focused her time learning about pet food and nutrition.

Nikki shares information on a range of dog nutrition topics: from how to create a homemade complete and balanced dog food recipes, to how to choose a dog food. Nikki strives to give dog parents the information they need in order to make the best nutrition decisions for their pup!

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