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How to Make a Hyperthyroid Cat Gain Weight: 4 Vet-Reviewed Ways to Help

Abyssinian cat check by vet
Image Credit: Nataly Mayak, Shutterstock
Last Updated on November 16, 2023 by Jessica Rossetti

Cats with hyperthyroidism can live healthier lives if their condition is managed. Since one major symptom of hyperthyroidism is weight loss, cat owners may be wondering what they can do to help their cats gain weight.

Your vet is your best source of information on how to help your hyperthyroid cat gain weight, but in this article, we show you four tips for helping your cat pack on the pounds.


What Is Hyperthyroidism?

Hyperthyroidism is a disease in cats that means their thyroid is overactive. Cats have two thyroid glands that help control and regulate their metabolism. When these glands produce too much of the thyroid hormone, hyperthyroidism is diagnosed.

One major symptom of this disease is weight loss. Your cat may be eating and seem to have a growing appetite, yet they continue to lose weight. Other symptoms include increased thirst, restlessness, weakness, increased urination, and a greasy or dull coat.

This condition can only be diagnosed with a blood test to determine the thyroid levels in the blood. If the disease is not managed, other organs can be affected, particularly the heart. It’s important to get the condition under control as soon as possible.

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The 4 Ways to Make a Hyperthyroid Cat Gain Weight

1. Control the Disease

vet giving drugs to cat
Image Credit: thodonal88, Shutterstock

Your cat can’t gain weight, no matter what you do, if you don’t manage their condition. The first step is getting your cat on the right medication to control their thyroid hormones. Antithyroid drugs are the most common treatment, and the cat will have to stay on this medication for the rest of their life.

The medication is usually given twice a day and will control the thyroid levels and keep them at a healthy number. Your cat may need several blood tests after the medication is administered to make sure it’s working as it should. Adjustments may need to be made until the proper dosage is found to control your cat’s thyroid hormones.

Other options such as surgery, Hill’s Y/D food and radio-iodine therapy may be an option for you cat which your vet can discuss with you.

2. Change to a Prescription Diet

In some cases, vets may suggest that a prescription diet be used, either alongside or instead of medication. If your cat’s thyroid levels can be controlled with prescription food, this food will have everything that your cat needs to also help them gain weight.

Within a few months of eating this food, your cat’s thyroid levels should return to normal. Weight gain will happen automatically without you having to do anything. Speak to your vet about a diet change to see if it’s right for your cat. However, it’s important to know that cats on a prescription diet for hyperthyroidism can never eat anything else —no treats, table scraps, scavenging or hunting outdoors, or garbage rummaging. Anything besides this food could disrupt their hormone levels.

3. Change Your Cat’s Food Yourself

devon rex cat eating
Image Credit: Veera, Shutterstock

Always speak to your vet before changing your cat’s food. But if a prescription food isn’t necessary for your cat, you can find another food on your own. If your cat still has a healthy kidney function, they will do well on a high-protein, high-energy food. This will help them recover muscle mass and gain weight.

If your cat’s kidneys have been affected by hyperthyroidism or another condition, they should eat a low-protein food.

4. Increase Exercise

Once your cat’s thyroid hormones have been controlled, regularly play with your cat and get them to engage in physical exercise each day. At least 15 minutes of activity can help them regain muscle mass and build up energy levels, which in turn, will make them hungrier so they’ll eat their meals.

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Final Thoughts

It can be scary when your cat is diagnosed with hyperthyroidism, but the good news is that the disease can be managed and your cat can live a healthy, happy life. Your vet will help you stabilize their thyroid hormones and weight. Once the condition is treated, your cat will be able to regain the weight that they lost and stay healthy.

Featured Image Credit: Nataly Mayak, Shutterstock

About the Author

Jessica Rossetti
Jessica Rossetti
Jessica is a lifelong resident of Chicago who has shared her home with furry, feathered, and scaly pets for over 30 years. Animal enthusiast since childhood Jessica owned and operated a pet care company. Nowadays, Jessica is a full-time writer who loves to explore all animal topics while contemplating the birds and squirrels enjoying the oasis of her backyard.

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