Hyperthyroidism in Cats – Diet Food, Treatment Costs & Savings.

Vet bills can be very expensive, particularly as pets get older. Common conditions like hyperthyroidism in cats and growths in dogs can appear rapidly as they age. The vast majority of us have our pets insured in order to cover some of these costs, however, this isn’t always practical. Some people prefer to have a savings pot for medical eventualities arising with their pets which is fine unless a medical condition arises early in the saving process or the condition requires specialist expensive treatment and care.  


I was born and raised on a farm in the Norfolk countryside with horses, cats, ducks, chickens and dogs all around me.  Whilst certain animals must have insurance for legal reasons, others do not…so how do you balance where you spend your money? 


I always used to believe in base cover in order to insure pets when they are young. It’s reasonably cheap initially due to the age of the pet and allows you to save a pot of emergency money alongside. As the pets became older, I would let the insurance lapse and begin to rely on the pot where needed. Now, this has worked fine in general and paid for vaccinations, boosters, flea and worming, plus regular check-ups at my local companion care veterinary centre. I’m now at a tipping point though due to my domestic longhair cat’s diagnosis of hyperthyroidism in cats.

What is hyperthyroidism in cats?

Hyperthyroidism is the most common hormone problems seen in older cats with in the UK.  Essentially it results in the overproduction of thyroid hormones the cat’s body. Whilst it’s not entirely clear why they occur, this condition is caused by harmless tumours located in the cat’s thyroid gland. These benign growths cause an enlargement of the thyroid gland in cats and dogs, causing them to not process iodine correctly due to the overproduction (hyper) or underproduction (hypo) of the thyroid hormones.


Whilst it can also be caused by more aggressive tumours (carcinoma), this is a rarity. In general, the growths result in an increased amount of the thyroid hormone circulating the cat’s body and in turn present as some of the following signs and symptoms that your cat might have hyperthyroidism:


  • Weight loss – if you notice that your cat seems extra hungry and is losing weight quickly to the degree where shoulders and ribs are becoming visible this may be a sign of hyperthyroidism in your cat.
  • Increased blood pressure – This will only be noticed if you specifically requested your veg to carry out a blood pressure check however it can be another indication that you may be at risk of stroke or vision issues due to hypothyroidism.
  • Degradation in quality of fur –  in some cats a noticeable difference in the quality of their coat may be an indication that the hormone is affecting how they process their food.
  • Increased heart rate –  the effect of the condition may mean that your cat has an increased heart rate or degree of hypertension this can be another indicator that the disease is having a toll on your cat’s body
  •  Increased drinking and urination – Again, this can be a sign things aren’t quite processing correctly inside your cat.
  • Overactive behaviours and appetite – One of the most common signs will be your cat eating food and constantly wanting more or scavenging for scraps and kills when hunting.


If you notice the above signs, consult your local vets and request a consultation. The Chances are they will request a set of bloods and do a physical examination to see if the thyroid gland in the neck enlarged. They will also, most likely, check for any hypertension (increased heart rate) and suggest a course of initial treatment.

What are the potential treatments for hyperthyroidism in cats?

My cat was 11 years old when I first started to notice an increased weight loss.   he has always been for birds and rabbits when outside. He would eat the rabbits, but leave the birds. Even at the age of 11 he would still hunt for animals outside and finish a bowl of food inside but seemed constantly hungry and this was at odds with his weight loss. For me,  the fact I could see and feel his ribs more every day was a sign I needed to take him along to the vets. 

thyroid food for cats
Photo: My 11-year-old cat, prior to his weight loss and diagnosis of hyperthyroidism.

In my case, the vet ran a full set of bloods and checked the heart and thyroid. He then suggested a prescription initially of felimazole thyroid medication. This medication is designed to help balance the cat’s system, but it can mask possible kidney function issues which is why after why prescribing the medication, I was invited to return for a second set of bloods after 12 weeks.  At this point the treatment costs for around £170 for examination, blood tests and prescriptions.  I found out a there was a significant cost difference in requesting the prescription from the vets or from an online vet pharmacy. For 100 Felimazol hyperthyroid medication tablets, the cost was £45.90 from Companion Care Vets or £19 if ordered via Pet Drugs Online. So if you’re being asked to try Felimazole 2.5mg 100 tablets, ask to source them yourself via Pet drugs online or a similar supplier.


After the initial period of observation on the tablets, my cat stopped losing weight and started to stabilise.  Once the twelve weeks of initial observation were over, I took him back to the vet for a second round or full bloods. Again this was around the £170 mark and with a slightly faster heartbeat than usual. We continued with a further few months of the tablet medication. A third examination and set of bloods were then run. Again, weight was okay, in fact, he had put on a small amount this time! But while most blood tests were okay, they wanted to raise the tablet amount slightly to get a better balance. At this point, my vet suggested the following options long term:


  • Radioactive Iodine Therapy
  • Thyroid Surgery
  • Special food for hyperthyroidism.


Below is what they mean and how I made my choice.


Radioactive iodine treatment for cats with hyperthyroidism

This was the course of treatment that was suggested via vets as the most favoured due to the fact that it has high levels of success at around 90%. The main problem with this course of treatment is finding a referral centre who are able to carry it out the length of hospitalization need for the cat and ultimately the overarching cost of the procedure. The cost for this course of treatment can be around £1,500 to £2,000 excluding the cost of care and hospitalization and food required around it.


Essentially the process involves a safe injection under the skin of the cat. This is taken up by the abnormal thyroid tissue which is destroyed.  This procedure does not affect the rest of the body and can offer a decent cure rate of 90%. Due to health and safety regulations around in his treatment (the hazardous nature of the substances used) your cat will need to stay in a specialised hospital for around 2 to 6 weeks. Whilst this treatment has a high success rate, I had to bear in mind the age of my cat, the significant cost, and the trauma/stress caused by travel and being in a different place – he really does not like travel and different settings.

Thyroid surgery (Thyroidectomy) 

This is the second option and is a type of surgery that involves the removal of the affected thyroid gland or glands. if your cat’s kidneys seem to be ok on that no trusting medication then this can be performed in theory on a day patient basis. There are risks with any type of surgery particularly those that use invasive surgery near the parathyroid (calcium regulator) and there is a risk that the additional glands close to the thyroid can be damaged, this can be fatal if there are complications. As there are two thyroid glands, there’s also no real way of telling whether it’s best to remove one or two. Sometimes a cat can have one removed, only to need a further operation to remove the second. The cost for this is still substantial at around £700-£800 and this cost doesn’t include is a cat needs to return for a second thyroidectomy.


Long Term Medication

As mentioned earlier my cat has been on felimazole medication now for around half a year.  If diagnosed with hyperthyroidism it is a long-term condition which will require constant tablet medication throughout their life and regular trips to the vet’s to monitor blood. Yearly, I would expect to have around 4-6 trips to the vets for weight checks and bloods (£170 each time) and then the annual cost of the tablet medication (100 tablets, twice a day = 50 days for £20, so £140 per year for medication). All in that’s an annual cost of £620 – £860


One thing to keep in mind is there’s a good chance your cat will need to increase their medication as they grow older so the cost will likely increase in relation to this. Also, if sourcing your medication for hyperthyroidism in cats direct from your vets the cost will likely be around £1000 total per year. If you’re considering this long term, use online suppliers like Pet Drugs Online to reduce the cost.


This medication should also not be handled or used by anyone who is pregnant.


Special Diet for Hyperthyroidism

This is the final option, a specially designed food for cats with hyperthyroidism. This is a suggestion for those that are usually indoors, as in order to allow this to work the cats will need to only eat this specialised food.  If your cat is young, active and always outside this may not be the course of treatment for you. However, if your cat is older and less of a candidate for the alternative treatments mentioned above, then this may be for you. Essentially, these special cat foods for thyroid care have controlled amounts of iodine. It’s taken down to minimal levels meaning that your cat’ system no longer needs to process using the thyroid. Effectively using this special diet allows the cat to bypass the issue and it’s ideal for when cats don’t stomach medication well.


For this to work, it’s important that your cat eats nothing else. No treats, no hunting trips outside, essentially your cat will need to convert to being in all the time to make this work. All cats adapt their routines differently, and as my cat has got older, he’s been increasingly happy to stay in and less prone to hunting so this ‘may’ be an option for him. Again, it’s not cheap though, so I’ve outlined the best cat food for thyroid car below along with details of how to save money on it. I welcome any thoughts or experiences in the comments of this article on how readers who have dealt with this condition have dealt with the decisions and treatments. Let us know your successes or experiences.

best food for hyperthyroidism in cats

What is the best cat food for hyperthyroidism?

A special diet that is iodine depleted has been launched by prescription diet company Hills. The Hills YD Thyroid Care cat food can bring down the thyroid hormone levels if used as a sole diet.  If your cats eat anything else the benefits gained from using Hills YD Thyroid Care cat food may be lost, so this is why converting them to house-bound cat status is virtually essential. Each cat also varies in terms of appetite and preference on wet and dry foods so these will play big factors in the cost of this approach, remember this is a life-long approach.


I read through a whole host of reviews for Hills Prescription Diet y/d Thyroid Care cat food and putting aside the huge variations in breeds and needs, owners seem to suggest it’s of benefit. They list increases in body weight and improve fur as quick improvements that they attribute to this food option. 


Hills themselves boast that their Y/D Thyroid Care cat food “supports kidney health with controlled phosphorus and low sodium. It helps to manage your cat’s health in 3 weeks by normalising thyroid hormone levels, with a visible improvement in skin and hair coat.”

hills YD thyroid care cat food
Photo: Available in both 1.5kg/5kg dry food bags and 156g tinned wet food, Hills Prescription Diet Y/D Thyroid Care is a cat food designed to support hyperthyroidism in cats.

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Where can I save money on hyperthyroidism cat food?


If you’re going to try the cat food approach, it’s worth running the numbers on cost again. Hill’s Prescription Diet thyroid care cat food cost for a year is approximately as follows based on a 4kg cat’s expected requirements:


Option 1: Sole Dry Food Cost – 50-65g per feed, available in 1.5kg or 5kg bags. Based on 1.5Kg bags being an average of £20 per bag, £40 per month or £480 annually.


Option 2: Mixed Wet / Dry Food Cost – 1 can and 10g dry per feed. Based on 156g cans or wet at around £15 per 12 cans. This diet option would work out at £50ish for dry and £915 for wet. This equates to £965 annually combined or £76 per month


The most reliable suppliers of the best food to support hyperthyroidism in cats in terms of cost are ZooPlus, Bitiba, Fetch, AniMed, Waitrose Pet, Pet Drugs Online and Pet Supermarket. Amazon is best for swift delivery, but the prices can vary. Best prices for 1.5kg Dry Food would be around £14. Monster Pet Supplies have the 5kg Dry bags for around £40. It’s also worth looking into using cashback accounts in order to save more on pet supplies.


A big part of any decision you make is going to be guided by what you think is best for your pet and the cost implications in relation to your insurance or budget. For myself, I’m going to give my cat the chance to try the least invasive forms (ie. the special diet option) and then monitor him over the months.  Ultimately I think most people decisions will be dictated by the age of their pet and the circumstances they see before them. If I end up going down the surgery route or the treatment for radioiodine therapy I will update this article accordingly and let you know how things go.


  1. Barbara Townend says:

    Thanks for this article. I’ve just privately adopted a 16 year old cat. I suspect she has thyroid problems and am taking her to the vets tomorrow to start the expensive process of keeping her alive as long as possible.I wonder, could I control this by only giving her home cooked meat? Have you tried this and ruled it out, would it work?

    1. Hi Barbara, In our case, we found that after diagnosis the recommendation was that a controlled diet might work but only if our cat was restricted to being an indoor cat to prevent other ingested foods. It always seemed to be a balance between medication and blood tests/weight checks. The only thing we can suggest is using your gut alongside the advice of your vet to so what you feel is in the best interests.

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