The 6 Best Cat Supplements of 2026 🐾

Most cats don’t need supplements — but the ones that do, REALLY do. We’ve used six over the past year for our four cats. Here’s what works and what’s marketing fluff.

How We Chose

We rated on: vet endorsement, evidence behind claims, ingredient quality, ease of administration (cats reject pills), and value. Always consult your vet before adding supplements — some interact with medications.

#1 — Best for Herpes Virus

Viralys L-Lysine Powder

Manages feline herpesvirus flare-ups (eye discharge, sneezing).

Why we picked it: If your cat has chronic eye/respiratory issues, Viralys L-Lysine is what most vets recommend first. Reduces FHV-1 flare-ups. Powder mixes into wet food easily.

Pros: ✅ Vet-recommended for FHV-1 ✅ Easy powder mix-in ✅ Effective for chronic eye/sneezing issues ✅ Affordable

Cons: ⚠️ Not for healthy cats (no benefit) ⚠️ Some cats detect taste ⚠️ Daily dosing required

#2 — Best Joint Support

Cosequin Joint Health

The vet-default for cat arthritis.

Why we picked it: Cosequin is the brand vets prescribe for older cats with stiff joints. Glucosamine + chondroitin. Sprinkle capsules on food.

Pros: ✅ Vet-prescribed default ✅ Real arthritis benefit ✅ Easy capsule sprinkle ✅ Good for senior cats

Cons: ⚠️ Pricey for ongoing use ⚠️ Takes 4-6 weeks to see benefit ⚠️ Not for kittens

#3 — Best Probiotic

Purina FortiFlora Probiotic

The probiotic vets hand out at clinics.

Why we picked it: FortiFlora is the gold-standard cat probiotic. Used after antibiotics, for diarrhea, or for cats with sensitive GI tracts.

Pros: ✅ Most-prescribed cat probiotic ✅ Sprinkle on food ✅ Works for diarrhea management ✅ Cats love the taste

Cons: ⚠️ Expensive long-term ⚠️ Single-use packets — wasteful

#4 — Best for Coat Health

Zesty Paws Wild Salmon Oil

Omega-3s for shiny coat and joint support.

Why we picked it: Zesty Paws Salmon Oil noticeably improves coat shine within 4 weeks. Wild-caught Alaskan salmon. Pump bottle for clean dosing.

Pros: ✅ Visible coat improvement ✅ Wild-caught ✅ Pump bottle ✅ Omega-3 dual-benefit (skin + joint)

Cons: ⚠️ Strong fish smell ⚠️ Refrigerate after opening ⚠️ Goes rancid if forgotten

#5 — Best Hairball Remedy

Tomlyn Laxatone Hairball Remedy

Lubricates digestive tract to pass hair instead of vomiting it.

Why we picked it: Tomlyn Laxatone is the standard hairball remedy. Tuna or salmon flavored gel. Cats accept it readily.

Pros: ✅ Cats actually take it ✅ Reduces hairball vomiting ✅ Multiple flavors ✅ Affordable

Cons: ⚠️ Petroleum-based (some owners avoid) ⚠️ Sticky/messy ⚠️ Daily-ish use needed

#6 — Best Calming

Zesty Paws Calming Bites

For thunderstorms, fireworks, vet visits, or new-pet introductions.

Why we picked it: Zesty Paws Calming Bites contain L-tryptophan + chamomile. Take effect 30-45 min before stress event. Mild effect, not heavy sedation.

Pros: ✅ Mild calming, not sedating ✅ Tasty soft chew ✅ Affordable ✅ No prescription needed

Cons: ⚠️ Mild effect (won’t fix severe anxiety) ⚠️ Takes time to kick in ⚠️ Not for daily use

FAQ

Should I supplement my healthy cat?

If your cat eats quality cat food, no. Supplements are for cats with specific issues — herpes virus, joint pain, GI sensitivity, anxiety, dull coat.

Can supplements harm cats?

Yes — some interact with medications, others (like fish oil) can become rancid. Always consult vet before starting.

Our Final Purr-spective

Viralys for FHV-1 cats. Cosequin for senior joint health. FortiFlora for GI issues. Salmon oil for coat shine. Laxatone for hairballs. Calming Bites for stress events.

— From our cats to yours 🐾