Spirulina platensis is a blue-green algae that is rich in protein, fatty acids, vitamins, and minerals. It is used to support healthy skin, metabolic health, lung function and the immune system in horses. It has anti-histamine, anti-inflammatory and anti-oxidant effects that could benefit horses with frequent illness or allergies. It can be used as a nutritional support for horses in stressful situations like competition and high-intensity exercise.
Spirulina is commonly referred to as an algae, but it is actually a naturally occurring bacteria that grows in saltwater and freshwater worldwide. Spirulina powder consists of two cyanobacterial species named Arthrospira platensis and Arthrospira maxima.
Spirulina is a nutritionally dense supplement that is easily digested. It is an excellent source of vitamins and minerals to support overall health and well-being of horses.
It is especially high in vitamin A and vitamin E which are important anti-oxidants that neutralize free radicals in all cells of the body. Horses fed mostly hay-based diets may be deficient in several vitamins and could benefit from the abundant vitamins and minerals found in spirulina.
This supplement is a rich source of the fatty acid gamma linolenic acid (GLA) . GLA is an anti-inflammatory omega-6 fatty acid. It has been shown to promote health benefits in humans including wound healing and tissue repair as well as exhibiting anti-bacterial and anti-viral effects. 
Spirulina powder is especially high in protein (up to 70%) and is considered a complete protein. This equine supplement might be particularly beneficial for young animals and heavily exercised horses to support their high protein needs. Although it provides all essential amino acids, it is considered low in lysine and methionine.
Horses affected by any of the following might benefit from spirulina supplementation:
- Have frequent immune challenges related to training, transportation and competition
- Slow recovery from exercise including tying up (exertional rhadomyolysis) and slow respiratory recovery
- Recurrent respiratory issues like heaves/COPD, chronic cough, sneezing, nasal discharge
- Prone to respiratory allergic reactions to dust or pollen
- Prone to skin conditions like sweet itch, an allergic reaction to insect bites from Culcoides (midges)
- Poor metabolic health (easy keepers) that have high body condition scores with abnormal fat deposits like cresty neck
- Equine Metabolic Syndrome – signs of this include frequent urination and drinking, obesity, and laminitis
Anecdotal reports suggest spirulina powder can support respiratory function in horses. Inflammatory airway disease commonly occurs in high performance horses but medications like clenbuterol and corticosteroids are prohibited in competition.
Dr. Eleanor Kellon reports on three cases in which a combination of spirulina platensis (20 grams given twice per day) and jiaogulan powder (2 grams given twice per day) improved respiratory function in performance horses with recurrent respiratory issues. Symptoms such as low energy and fatigue, chronic cough, sneezing, head shaking, nasal discharge and respiratory recovery were improved in the three horses studied. 
In another case report, three months of spirulina supplementation was shown to support improved metabolic health and weight loss in horses with equine metabolic syndrome.
Horses were fed 500 g per day of a commercial feed containing Spirulina platensis. At the end of the three months, horses had diminished cresty neck scores, lower fasting insulin levels and improved glucose tolerance. These benefits were attributed to the anti-inflammatory and anti-oxidant effects of phycocyanin – a selenium-rich protein found in spirulina. 
The feeding rate for spirulina varies depending on your horse’s condition and current diet. A typical serving size is 20 grams given twice a day for a 500 kg horse. Some horses may be hesitant to consume spirulina powder due to its unique smell. Combining it with Mad Barn’s W-3 oil essential fatty acid supplement may help mask the smell for picky eaters.
Spirulina is Generally Recognized as Safe by the US Food and Drug Administration. It grows best in lakes with very high pH which is not a favorable environment for many other microbes. Therefore, there is low risk of contamination with other microorganisms.
You should always consult a qualified nutritionist before altering your feed program. Submit your horse’s diet for analysis online and one of our equine nutritionists will be happy to provide a complementary review.
- Roughan, Grattan P. Spirulina: A source of dietary gamma-linolenic acid? J Sci Food Agri. 1989.
- Kellon, Eleanor. Use of the Herb Gynostemma Pentaphyllum and the Blue-green Algae Spirulina Platensis in Horses. Equine Congress
- Nawrocka, Daria et al. Spirulina platensis Improves Mitochondrial Function Impaired by Elevated Oxidative Stress in Adipose-Derived Mesenchymal Stromal Cells (ASCs) and Intestinal Epithelial Cells (IECs), and Enhances Insulin Sensitivity in Equine Metabolic Syndrome (EMS) Horses. Marine Drugs. 2017.
- Mittelman, N.S. et al. Presumptive Iatrogenic Microcystin? Associated Liver Failure and Encephalopathy in a Holsteiner Gelding . J Vet Intern Med. 2016.
- Roy-Lachapelle, Audrey et al. Detection of Cyanotoxins in Algae Dietary Supplements. Toxins. 2017.
To determine the appropriate inclusion rate for Spirulina in your horse’s diet, submit your horse’s feeding program for analysis online and one of our equine nutritionists will be happy to provide a complementary review.
|< 200 kg||1/2 scoop||10 g|
|200 – 500 kg||1 scoop||20 g|
|> 500 kg||2 scoops||40 g|
|1 scoop = 29.6 cc = 20 grams|
A scale should be used with all individual ingredients to ensure accurate dosing.
|Spirulina Powder||20 grams two times per day|
|Quantity||Days Supplied||Serving Size||Cost Per Day|
|Cost Per Day||20 g / day||$0.67|
|40 g / day||$1.35|
Customer Questions About This Product
- Is this product USEF and FEI legal?
- Q Is this product USEF and FEI legal?A Yes, according to their 2022 prohibited substances lists What would the dosage be for a 1400lb horse?
- Q What would the dosage be for a 1400lb horse?A For a 1400lb horse, you can feed 2 scoops (40g) per day of Spirulina. Is there a full nutritional or guaranteed analysis for this product?
- Q Is there a full nutritional or guaranteed analysis for this product?A Hi Sarah, The product is pure spirulina powder. If you'd like to see the nutritional information for spirulina you can view that at https://madbarn.com/feeds/spirulina/ Does this contain DHA? I'm looking to supplement a pregnant mare.
- Q Does this contain DHA? I'm looking to supplement a pregnant mare.A Spirulina is a source of DHA. However, or w-3 Oil would provide higher levels of DHA if that is what you are primarily interested in: https://madbarn.com/product/w-3-oil/ Where is your Spirulina sourced from? Does it go through any testing before being used in your products?
- Q Where is your Spirulina sourced from? Does it go through any testing before being used in your pr...... Read moreA The product is sourced out of the US. We test all incoming ingredients for various contaminants and also to ensure they are within specification. How long does 5kg of spirulina last?
- Q How long does 5kg of spirulina last?A The typical feeding rate for Spirulina is 20 grams fed one to two times per day. If feeding 20 grams per day, the 5 kg package will last 250 days. If feeding 40 grams per day, the 5 kg package will last 125 days. Can you feed the spirulina with Visceral+?
- Q Can you feed the spirulina with Visceral+?A Yes, Spirulina can be fed with Visceral+ to support gut health and horses with ulcers. How much is 2k in pounds? How long will it last a 1000 pound horse?
- Q How much is 2k in pounds? How long will it last a 1000 pound horse?A 2kg is 4.4 lbs. If you are feeding 20 grams twice per day it will last 50 days Would Spirulina be adequate to use as a vitamin/mineral supplement for a IR/borderline PPID pony?
- Q Would Spirulina be adequate to use as a vitamin/mineral supplement for a IR/borderline PPID pony?A
Spirulina does contain many minerals, but it will not adequately balance a diet. You still need to use a good mineral and vitamin supplement like Omneity or AminoTrace+ Hi, how many grams of protein in 20 grams of recommended feeding dose?
- Q Hi, how many grams of protein in 20 grams of recommended feeding dose?A
11-12 grams of protein. Can I feed this and chasteberry to an IR horse who is currently using Pergolide?
- Q Can I feed this and chasteberry to an IR horse who is currently using Pergolide?A
Hi Kate - Yes, Spirulina and Chasteberry can be given together to provide nutritional support for horses that have Cushing's disease and are currently on Pergolide.
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