By Dial A Vet Veterinary Team
Chlorella turns up in smoothies, green powders and tablets, and it is often marketed as a superfood. It is natural to ask whether a little might help your cat too. The honest answer is that we do not know of good evidence that it does, and supplements are not without risks. If your cat has eaten a tablet or two from your bottle, there is usually no need to panic, but it is not something to start giving without talking to your vet.
Key takeaways
- Chlorella is a single-celled green algae sold as a powder or tablet supplement for people.
- Claims about detox, immunity and coat health in cats have not been established by good research in cats.
- A 2024 review notes chlorella can accumulate heavy metals from its environment, so product quality control matters.
- The same review notes chlorella has a hard cell wall that makes it difficult to digest without processing.
- A complete and balanced cat food is designed to meet your cat's nutritional needs.
- Related reading: vomiting and diarrhoea in cats.
What is chlorella?
Chlorella vulgaris is a microscopic green algae. A 2024 review in the Journal of Food Science describes it as containing protein, chlorophyll, carbohydrates, lipids and several vitamins, and explains why it is being studied as a food ingredient for people. It is grown, dried and sold as powders, tablets and capsules.
Does chlorella help cats?
Many websites claim chlorella can detoxify, boost immunity or improve a cat's coat. Those claims mostly borrow from human marketing. We are not aware of good quality studies showing these benefits in cats, and the review above calls for more solid clinical research even in people.
Cats are obligate carnivores. RSPCA Australia explains that they do not have some of the enzymes and body processes other animals use to digest and convert plant nutrients. A plant-based supplement is not a shortcut to better nutrition for a cat.
Possible concerns
Quality and contaminants. The review notes chlorella can accumulate heavy metals from its environment and needs stringent quality control. Supplements for people are made to different standards in different countries, and products are not tested for cats.
Digestibility. The review notes chlorella has a hard cell wall that makes it difficult to digest unless it is processed. In cats, an unfamiliar plant supplement may simply cause a stomach upset.
Medication interactions. Supplements can interact with medications. If your cat takes any regular medicine, check with your vet before giving any supplement.
Other ingredients. Green powder blends for people may contain other herbs, sweeteners or flavourings. Check the full label.
If your cat ate chlorella tablets or powder
Most cats that eat a small amount of plain chlorella will have no problem, or a mild upset stomach at most. Watch for:
- Vomiting
- Diarrhoea
- Reduced appetite
- Lethargy
When to call a vet or the Animal Poisons Helpline
Call your vet or the Animal Poisons Helpline (1300 869 738) if your cat ate a large amount, ate a blended supplement with other ingredients, or if you are not sure what the product contains. Have the bottle with you when you call.
Call your vet if vomiting or diarrhoea lasts more than a day, if your cat stops eating, or if your cat has an ongoing health condition.
Seek urgent care for weakness, collapse, seizures or breathing difficulty.
How vets help
Your vet will look at the label, ask how much was eaten and examine your cat if needed. Most cases only need monitoring. If you are interested in supplements for your cat, your vet can talk through the evidence, look at your cat's diet and suggest options that have been studied in cats.
Better ways to support your cat's health
- Feed a complete and balanced commercial cat food suited to your cat's life stage
- Keep up regular vet checks
- Keep your cat at a healthy weight
- Ask your vet before adding any supplement
FAQ
My cat ate one of my chlorella tablets. Is that an emergency?
Usually not. Watch for an upset stomach, and call your vet if you are worried or if the product contained other ingredients.
Can I give chlorella for my cat's coat?
There is no good evidence it helps. A dull coat can have medical causes, so a vet check is a better first step.
Is spirulina the same as chlorella?
No. They are different products. The same advice applies: talk to your vet before giving any supplement.
Is chlorella toxic to cats?
It is not known as a cat toxin, but it has not been well studied in cats and quality varies between products.
Talk with a vet
If you are thinking about supplements for your cat, or your cat got into your green powder, a Dial A Vet veterinarian can help. Book a Dial A Vet consult.
References
- Wang CA, Onyeaka H, Miri T, Soltani F. J Food Sci. 2024;89(12):8231. Chlorella vulgaris as a food substitute: Applications and benefits in the food industry.
- RSPCA Knowledgebase. What should I feed my cat?.
- Animal Poisons Helpline (Australia, 1300 869 738). Animal Poisons Helpline | 24/7 Pet Poisoning Advice.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.