Thyforon (formerly called Forthyron) for Dogs

Thyforon (formerly called Forthyron) for Dogs
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200ug Tablet » 250 Tablets
400ug Tablet » Priced per Tablet
800ug Tablet » Priced per Tablet

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  • 200ug Tablet » 250 Tablets £39.99
  • 200ug Tablet » Priced per Tablet £0.17
  • 400ug Tablet » 250 Tablets £49.99
  • 400ug Tablet » Priced per Tablet £0.28
  • 800ug Tablet » 250 Tablets £96.99
  • 800ug Tablet » Priced per Tablet £0.39

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£0.17 to £96.99


Thyforon is the new form of the well established tablet formerly called Forthyron.  They are used to treat an under-active thyroid gland in dogs (known medically as hypothyroidism). This condition is common in middle aged dogs. It is not a life threatening condition, but it is often associated with a poor coat  and skin problems. It also tends to make affected individuals lethargic and overweight.  Reproductive problems are often seen in breeding animals too.Treatment of hypothyroidism in dogs is simple and safe using Thyforon or Forthyron. Both are tablets containing levothyroxine sodium. This is a synthetic product which is chemically identical to the naturally occurring hormone thyroxine, or “T4”. It is used to supplement deficient hormone levels in the affected dog and is to be used long term. Side effects are very rare with Thyforon/Forthyron unless it is significantly overdosed. Since it is chemically identical to the natural hormone, side effects only tend to occur due to increased effect. If a previously lethargic dog becomes more active due to improved thyroid hormone levels,  this can put a strain on the body if there are underlying heart or arthritic problems. Therefore it is sensible for your vet to assess the overall condition of your dog, including any other possible hormonal problems, before starting therapy. Thyforon tablets are different from Forthyron tablets is that they are flavoured to make them palatable to dogs, with most dogs taking them happily as treats

Treatment usually has to be given for several weeks before improvement in the skin and coat are seen. Dogs become more lively and alert usually more quickly.

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Medication Datasheets

Reviews (42)

Summary of Reviews for Thyforon (formerly called Forthyron) for Dogs

Overall 5
Ease Of Use
Value For Money
Absence Of Side Effects
42 out of 42 (100%) customers would recommend this product.
5 stars (35 reviews)
4 stars (5 reviews)
3 stars (2 reviews)
2 stars (0 reviews)
1 stars (0 reviews)

Only verified purchasers of this product can leave a review.

55 Good
Verified Purchase

By on 13 November 2023

She has no choice except to be on it.

Customer recommends this product

55 Calibra
Verified Purchase

By on 17 January 2023

After trying around 6 different brands for dogs with renal failure, this was the only dog food our pet would tolerate so I would definitely recommend this product.

Customer recommends this product

55 Great
Verified Purchase

By on 18 March 2021

My dog doesnt know she is taking tablets but what a different they are to her, and Viovet extremely professional from start to finish

Customer recommends this product

55 Hypothyroid dog
Verified Purchase

By on 15 March 2021

Does the job! His levels are now normal. No side effects, just a happy boy who feels well again.

Customer recommends this product

55 Great, reliable service and product
Verified Purchase

By on 14 March 2021

I buy these tablets online as it's much cheaper than through vets. I've never had an issue with delivery and viovet are quick to process the prescription. Great service!

Customer recommends this product

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Q & A

Below are some recent questions we've received regarding Thyforon (formerly called Forthyron) for Dogs, including answers from our team.

15 June 2015 at 6:29pm

About Thyroxine

Ivan Cheung

HI My senior doggie must need to had
"Thyroxine (ThyroMed)0.2mg twice time per day,is't same with this product?

  • VioVet Staff

There are several different brands of thyroid hormone tablets for use in dogs. All of them can be used once a day or twice a day. Some dogs do appear to respond better to twice daily dosing and some vets always advise this. Other vets will try once per day at first. The active ingredient is the same in all the top brands, so you should aim to give a new brand in the same way as you gave the previous brand, while always checking with your own vet first. You should probably expect to give this product twice per day to your dog.

5 January 2014 at 10:58pm

Delivery to Germany


hello there,

do you deliver "Typhoron" (prescription) to Germany or only within U.K.?

sincerely yours


  • VioVet Staff

If you send us a veterinary prescription to cover the medication you order, then we can send medication to Germany.

Delivery Information