Fight Plaque & Bad Breath – Clean Teeth Without Brushing!

Where it's found

This brown algae grows on the rocky, tide-washed shores of the North Atlantic, from Norway and Iceland to Ireland, Scotland and the coast of Maine. It's harvested, dried and milled into a fine powder. It's the same brown algae used in the cat dental powders that carry the Veterinary Oral Health Council (VOHC) seal for plaque and tartar.

Why it helps

It works differently from a toothpaste and isn't thought to act on contact with the teeth. Researchers believe compounds from the algae are absorbed in the gut and come back out in your cat's saliva. That way every tooth surface is bathed in them all day, including the back molars a brush rarely reaches.

Its sulfur-rich carbohydrates and natural polyphenols appear to make it harder for plaque bacteria to stick to the tooth and multiply. Less plaque sticking means less soft plaque hardening into tartar, and fewer of the bacteria that give off the sulfur gases behind bad breath.

The research

In a 90-day randomized, placebo-controlled trial, 60 dogs were given brown algae treats every day after a professional cleaning. By day 90 the algae group had about 38% lower plaque scores than the placebo group, lower tartar at every check-in, and 46% lower breath-sulfur readings. The algae product's manufacturer funded the trial, and the exact mechanism is still being studied.

Gawor et al., Frontiers in Veterinary Science, 2018. VOHC accepted-products list (cats): ProDen PlaqueOff® Powder, plaque and tartar.

Why 330 mg

330 mg is the amount in one scoop of the brown algae powder used in published clinical work, split across four treats (82.5 mg each) for a steady supply morning and night. We deliberately don't go higher: brown algae naturally contains iodine, and 330 mg keeps it within a safe daily range for cats.

Brown algae is a natural source of iodine. If your cat has a thyroid condition, is on a prescription or iodine-restricted diet, or is pregnant or nursing, check with your vet before starting.

Where it's found

Propolis is made by honeybees. They collect sticky resin from tree buds like poplar and birch, then mix it with beeswax to seal cracks in the hive and keep it free of germs. It's naturally rich in flavonoids and phenolic acids, the protective plant compounds behind its benefits. We use an alcohol-free, lab-tested propolis extract, because the alcohol tinctures sold for people aren't safe for cats.

Why it helps

Most of the smell in "cat breath" comes from sulfur gases made by bacteria living along the gumline. Propolis compounds are thought to damage those bacteria's protective outer layer and slow the genes they use to cause trouble. Some of them may also react with the sulfur gas itself and neutralize the smell. Its antioxidant, soothing compounds may also help calm red, irritated gums.

The research

In a 2025 placebo-controlled study, cats with bad breath ate a chicken treat with propolis and lysozyme every day for 28 days. Over those four weeks the propolis group showed about 35% lower breath-sulfur levels, about 51% lower plaque scores, and about 61% lower gum-inflammation scores, while the plain-treat group stayed flat. It was a small study (24 cats), so we treat it as promising, not final.

Li et al., Antioxidants 14(6):639, 2025.

Why 6 mg

That study used exactly 6 mg of propolis a day, and that's what four Kiroo treats deliver (1.5 mg each). We stick to the amount that's been tested in cats.

Where it's found

Lysozyme is one of the body's built-in defenses. It's found naturally in saliva and tears, and it's abundant in egg white, which is where ours comes from. Adding a little more simply tops up what your cat's mouth already uses to keep bacteria in check.

Why it helps

Lysozyme works like molecular scissors. It cuts through the mesh-like wall around the early-settler bacteria that first coat a clean tooth and give the rest of plaque something to grab onto. Breaking them down helps keep young plaque from building into a thick, stubborn film.

On its own it's weaker against odor bacteria, because their extra outer layer shields them. Propolis and lactoferrin both weaken that outer layer, so lysozyme can finish the job. That's why the three are used together.

The research

Lysozyme was the second half of the 2025 cat study above. The researchers credit the propolis-lysozyme pairing for the drop in plaque, gum inflammation and breath odor.

Li et al., Antioxidants 14(6):639, 2025.

Why 4 mg

The study used 4 mg a day, and four Kiroo treats deliver the same 4 mg (1 mg each).

Where it's found

Lactoferrin is a protein found naturally in milk, saliva and tears, where it helps protect the body against germs. Ours is purified from cow's milk. It's the protein only, not the milk sugar (lactose) that upsets many cats' stomachs.

Why it helps

Most bacteria need iron to grow. Lactoferrin grabs onto iron and holds it, so the bacteria living along the gumline have less to feed on. It can also loosen the outer layer of odor bacteria, which lets lysozyme do its work, and it helps quiet the inflammation that makes gums red and tender.

The research

Lactoferrin has been used by vets for cats with severe gum inflammation (chronic gingivostomatitis), and it's a key ingredient alongside an oral probiotic in DentalBio, a dental supplement for cats and dogs from Japan's Kyoritsu Seiyaku. Lab studies show it working together with lysozyme against mouth bacteria.

Why 20 mg

20 mg a day (5 mg per treat) adds a steady supply on top of what your cat's saliva already makes. It goes into the coating after baking, because high heat can break the protein down.

Contains a milk protein. If your cat has a known dairy allergy, check with your vet first.

Where it's found

Zinc is an essential mineral your cat already gets from meat. Zinc gluconate is a gentle, easily absorbed form of it. It's the zinc used in Maxi/Guard oral gels that vets have used on cats and dogs for years.

Why it helps

Zinc works on bad breath two ways. First, it binds to the smelly sulfur gases in the mouth and turns them into odorless compounds. Second, it slows down the plaque bacteria that make those gases in the first place. Zinc is also part of how gum tissue repairs itself day to day.

The research

Zinc is one of the most widely used breath and plaque actives in oral care for people and pets. In vet medicine, zinc-based oral gels like Maxi/Guard are a long-standing home-care option for cats.

Why 20 mg

20 mg of zinc gluconate provides about 3 mg of zinc a day (0.7 mg per treat). That's less than the zinc in a complete cat food, so it adds support without overdoing it.

Where it's found

Vitamin C is the familiar antioxidant in citrus fruit, berries and bell peppers. Ascorbic acid is its pure form. Cats make some vitamin C on their own in the liver, so we add a small extra amount where it's needed most.

Why it helps

Your cat's gums are built from collagen, the connective tissue that holds each tooth snugly in place. The enzymes that build collagen can't work without vitamin C. It's also an antioxidant that helps neutralize the free radicals released when plaque bacteria irritate the gumline.

The research

The link between vitamin C and gum health is best studied in people, where low levels are tied to bleeding, inflamed gums. Cat-specific studies are limited, so we use it as a modest top-up. It's also a common active in leading pet supplements.

Why 10 mg

10 mg a day (2.5 mg per treat) is a gentle top-up for an animal that already makes its own. It goes into the coating after baking, because heat breaks it down.

Vitamin C can break down into oxalate. If your cat has had calcium oxalate bladder stones, check with your vet before starting.

Where it's found

Taurine is an amino acid found in meat and fish, especially heart muscle and seafood. Cats can't make enough of it themselves, so it's one of the nutrients they must get from their diet.

Why it helps

Taurine is an antioxidant that helps tissues cope with everyday wear, including the soft tissue of the gums. In vet oral gels it's paired with zinc to support a healthy gumline. Beyond the mouth, it's essential for a cat's heart, eyes and digestion.

The research

Taurine's role in cat health is well established, and a lack of it is linked to heart and vision problems. In oral care, it's paired with zinc in Maxi/Guard gels and included in other cat dental chews such as VetriScience Healthy Mouth Bites.

Why 25 mg

25 mg a day (6.25 mg per treat) is a small bonus on top of what a complete cat food provides. Excess taurine is simply passed out, so it's one of the safest nutrients to add.

Where it's found

Coenzyme Q10 is made by the body and found in nearly every cell. It's most concentrated in hard-working organs like the heart and liver, which is also where cats get it in their diet.

Why it helps

CoQ10 helps cells turn food into energy and protects them from oxidative damage. Gum tissue that's constantly irritated by plaque bacteria uses a lot of energy to repair itself, and CoQ10 supports that process.

The research

Studies in people have linked low CoQ10 levels in gum tissue to gum disease, with some showing improvement when it's added. Pet studies are limited, so we include it as a supporting antioxidant. It's also used in cat dental chews such as VetriScience Healthy Mouth Bites.

Why 5 mg

5 mg a day (1.25 mg per treat) is a gentle daily amount for a cat-sized body.