Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

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

loss weight or skinny cat

Cats with hyperthyroidism can live healthier lives if their condition is managed. Since one major sign of hyperthyroidism is weight loss, cat owners may wonder how to help their cats gain weight.

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

divider 1 paws

What Is Hyperthyroidism?

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

One sign of the disease is weight loss. Your cat may be eating and seem to have a growing appetite, yet they continue to lose weight. Other signs include increased thirst, restlessness, weakness, 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 vital to get the condition under control as soon as possible.

devon rex cat eating
Image By: Veera, Shutterstock

The 4 Ways to Make a Hyperthyroid Cat Gain Weight

1. Control the Disease

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 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 ensure it works as it should. Adjustments may need to be made until the proper dosage to control your cat’s thyroid hormones is found.

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

vet giving drugs to cat
Image Credit: thodonal88, Shutterstock

2. Change to a Prescription Diet

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

After eating the food for a few months, your cat’s thyroid levels should return to normal. Weight gain will happen automatically without you having to do anything. Speak to a vet about a diet change to see if it’s right for your cat.

However, it’s essential 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

Always speak to a vet before changing your cat’s food, but if a prescription food isn’t necessary, you can find another food on your own. If your cat 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 low-protein food.

Need veterinary advice but can't get to the clinic? Catster recommends PangoVet, our online veterinary service. Talk to a vet online and get the answers and advice you need for your cat without having to leave your living room — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money


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.

divider 1 paws

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: Aun25, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Cat Shedding: What’s Normal & When to Call the Vet (Vet Reviewed)

Some cats shed more than others, but knowing what’s normal for your own cat is useful. Excessive shedding can be a sign that...

How Much Does an Oriental Shorthair Cat Cost? 2026 Price Guide

While Oriental Shorthairs are closely related to the Siamese cat, they have been developed into their breed. Unlike the Siamese, they come in...

How to Clean a Cat’s Butt: Vet-Approved Step-by-Step Guide

Cats are generally experts at cleaning themselves, butts included. But sometimes, your feline pal needs a little extra help in the hygiene department....

6 Vet-Approved Natural Home Remedies to Treat Scabs on Cats

Frequent and persistent scabbing on your cat’s body is not normal. Keep track of where the scabs appear on your cat’s body and...

More related

How to Remove Cat Pee Smell From a Couch: 5 Quick & Easy Tips

The smell of cat urine is incredibly strong and can permeate throughout an entire house, making the whole building smell like a litter...

Cat FIP Signs & Treatment: Vet-Reviewed Facts & FAQ

Feline infectious peritonitis (FIP) is a disease caused by a mutation of the FeCv virus. Known as the feline coronavirus, FeCv isn’t the...

When To Give Up on Cats Getting Along: Facts & Tips to Introduce Them Safely

Experts generally agree that it can take up to a year for cats to forge any kind of relationship, even if it is...

10 Best Cat Treats for Picky Cats (2026) – Reviews & Top Picks

You spend hours at the pet store picking out the best treats for your cat, only for them to be rejected without so...

Keep reading

Are Plug-In Air Fresheners Bad for Cats? Vet Approved Facts & Advice

We all love our cats. What we don’t love is the odors they leave behind. Of course, most pet parents clean their homes, but we also want our houses to smell good, and that’s where air fresheners come in. However,...

Sad kitten

Can Cats Eat Jalapeños? Vet-Reviewed Facts & FAQ

Jalapeños are tasty, spicy peppers that people enjoy in a variety of dishes and are prepared in lots of different ways, such as raw, sauteed, and pickled. These peppers may be an enjoyable food item for people, but what about...

Can Cats Eat Jalapeños

Do Cats Think Dogs Are Cats? Vet-Reviewed Science & Info

Even though cats and dogs have a negative association, many get along very well. If you have dogs and cats, you probably already know that! Seeing cats and dogs interact can range anywhere from cute to hilarious, and sometimes, it...

Cat and dog together on sofa indoors

Raw Food Diet for Cats: Vet-Approved Pros & Cons

Choosing the proper diet for your cat is an incredibly difficult decision. You must balance your desire to give your cat what’s best and consider their finicky nature. Time and effort are also big considerations. Raw pet food is all...

raw cat food

How Do I Calm a Cat Down for a Bath? 6 Vet-Approved Tips to Try

Oh, the dreaded cat bath time. Thankfully, this process will only be necessary on exceptionally rare occasions, perhaps even never throughout your cat’s life. We can admit that we’re grateful for their stellar self-grooming abilities, but your cat may need...

Bubble bath a small gray stray cat

Acana Cat Food Review 2026: Recalls, Pros & Cons

Review Summary Introduction ACANA has various premium cat food recipes and flavors that are rich with animal protein and nutrients to ensure that your cat gets everything that they need for a complete and balanced meal. It has diets specifically...

Acana Cat Food Review

Hound and Gatos Cat Food Review 2026: Recalls, Pros & Cons

Review Summary If you’re interested in getting your cat back to their historical roots with a meat-centric diet, you’re not alone. That’s the whole premise behind Hound & Gatos, a family-owned company that started in 2010. Although their recipes aren’t...

Hound & Gatos Cat Food Review

Why Do Cats Act Weird When Scratching the Base of Their Tail? 10 Vet-Reviewed Reasons

It’s not uncommon for cats to act weird when you scratch the base of their tail. This area is quite sensitive, and cats respond one way or another. Additionally, a tail that sticks straight upright into the air is referred...

young cat breathing heavily

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.