With a truly vast array of supplements on the shelves, all promising to help maintain our cats’ in tip-top health… Which ones are actually being used by vets? What do vets use for their own pets? We asked our cat-owning vet panel what they used for their cats, and more importantly why!

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In 2021, we asked a group of our vet bloggers a whole range of questions about their pets – dogs and cats. Our cat-owning respondents were:

You can read more about them and their pets here.

So, what supplements do you use in your cats?

Samantha Coe

I do not use any supplements for my cat at the moment although I am  sure I will use such products as he gets older. Presently he seems to be a very healthy boy. Over time I will probably give him supplements to help with his joints and general mobility.  

Cassandra Longhi-Browne

I have used Zylkene in the past in the lead up to stressful situations like a house move as one can be prone to stress related cystitis.

Lawrence Dodi

I do not give my cat any supplements.

Lizzie Youens

Jazzy is a bit of a stressy boy, and we used to have a lot of issues with him urine spraying in the house. He’s much better in our new house which has more space for him away from Pi and the children. But we use a Feliway plug-in as it seemed to help. Certainly, my husband is convinced that he seems more flighty and agitated when it runs out. I’m not as convinced but it certainly does no harm so we keep it re-filled. 

Louisa Marcombes

No, but mainly because I have been super-lucky with my cats. I have not really had to manage any health conditions where supplementation may have been a good idea. The difficulty with this class of treatments, generally, is they have little or no evidence to back up their use. On the other hand there is quite a bit of anecdotal evidence that they can help for problems like cystitis and stress-related issues with relatively few side effects. So I would definitely consider trying them for my cat if I thought they could be of benefit.

Sarah Cooper

Unfortunately both my cats were both born with a problem affecting their hindlegs which makes them more likely to develop arthritis as they get older. With this in mind, they are currently on a joint supplement that contains ingredients such as glucosamine, chondroitin and omega 3 essential fatty acids to try and slow the degenerative changes and help keep them pain free.

Sarah Hunter

No, she doesn’t get anything. Although I will probably add a joint supplement to her diet when she gets a bit older.

So why are vets so cautious about supplements?

The real reason is that there’s very little high-quality published evidence into how well they work. To get a pharmaceutical product licensed for sale, the manufacturers have to pay for research to establish how safe it is, and how effective it is.

However, there are no such licensing requirements for supplements. As long as the ingredients are safe, then they can be sold. And this is fine – but it means that if you want to know “is it worth it?”, the data just isn’t available in most cases. Most supplement companies have bigger marketing budgets than research departments. Which is why the products look so convincing on a superficial read! But if you did deeper, it’s very unlikely that solid, high-quality studies have been done and published.

Why is there so little published evidence?

The reason is a quirk in the way medicines are regulated in the UK (and in the EU, as it happens). If a product is demonstrated to be effective at treating, managing or preventing a disease, it automatically becomes a “Veterinary Medicinal Product”. However, as soon as that happens, it comes under the regulation of the medicines regulator (in the UK, the Veterinary Medicines Directorate).

And once they have decided that the balance of evidence is such that the product is effective, it becomes illegal to sell it until the manufacturer does all those studies and applies for a license. This is why it is now illegal to sell CBD without a prescription – not because the VMD think it doesn’t work, but because they believe that it does!

So here’s the problem: as soon as a supplement company publishes research showing their product works, there is a risk that the VMD will believe it. If the VMD believe it, then the company has to stop selling their product and spend millions of pounds providing the evidence that a drug needs.

Or they can just sit on any evidence they have and hope that good marketing continues to sell the product, instead of solid science. 

And that’s why vets are generally cautious – because we have no way of knowing in many cases whether these supplements are doing any good or not. They probably are useful (in my opinion!), but we can’t prove it.

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