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Thyro-L

(70 reviews)
Veterinary Diet Item
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Thyro-L

$38.99
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Product Overview

Thyro-L is useful in correcting conditions caused by hypothyroidism in horses (low circulating thyroid hormone).
Thyro- L is indecated for use in horses for correction of conditions associated with low circulating thyroid hormone (hypothyroidism). Thyro-L can be administered by mixing the daily dose in the concentrate or by top dressing on grain, preferably rolled or ground.
For use in horses.
Thyroid-L is useful in correcting conditions associated with hypothyroidism (low circulating thyroid hormone) in horses.
This product is orally administered and uses levothyroxine sodium to correct conditions associated with hypothyroidism.
When administered at the recommended dosage, no adverse reactions should occur. Contact your veterinarian if you notice any unusual symptoms in your horse. If an allergic reaction occurs, signs can include:
  • Coma
  • Cold limbs
  • Pale gums
  • Seizures
  • Shock
  • Sudden diarrhea
  • Scratching
  • Hives
  • Swelling of the face
If you notice any signs of an allergic reaction, seek immediate veterinary care.
Levothyroxine Sodium
Immediately contact your closest emergency animal hospital.
  • Federal law mandates that this drug may only be used by or prescribed by a licensed veterinarian.
  • Keep away from children.
  • Not approved by the FDA.
  • Proceed with caution in administering to any animal with hypertension, serious heart disease, or any other condition in which a sharp increase in metabolic rate can pose a hazard to the animal.
  • Safe use in pregnant animals has not been proven.
1 lb or 10 lbs
Lloyd Laboratories Inc
Administer with caution to animals with clinically significant heart disease, hypertension or other complications for which a sharply increased metabolic rate might prove hazardous. Use in pregnant mares has not been evaluated.
The suggested initial dose is 0.5 to 3.0 mg levothyroxine sodium (T-4) per 100 pounds of body weight (1 to 6 mg per 100 kg) once per day or in divided doses. Response to the administration of Thyro-L should be evaluated clinically until an adequate maintenance dose is established. In most horses, this is usually in the range of 6 to 36 mg total daily dose of T-4. Serum T-3 and T-4 values can vary greatly among individual horses on thyroid supplementation. Dosages should be individualized and animals should be monitored daily for clinical signs of hyperthyroidism or hypersensitivity.
Levothyroxine Sodium 

About This Product

Customer Reviews

4.9
70 reviews
5 62
4 8
3 0
2 0
1 0
Customer review photo
Darlene M Verified Purchase
September 6, 2026

Keeps my horse healthy

Beverley B Verified Purchase
April 16, 2025

My gelding was diagnosed as metabolic and has been getting thyro-l ever since. He responded well and will continue with the supplement.

Abbey J Verified Purchase
February 28, 2024

My horse is insulin-resistant. This medication helps her feel so much better and keeps the weight off!

Vanetta E Verified Purchase
July 27, 2022

It does a great job keeping excess weight off my mare with EMS.

BURTON R Verified Purchase
January 25, 2022

Lowest price for this product.

Lisa C Verified Purchase
January 25, 2022

My donkey has Cushings disease and it was recommended by his vet to use the Thyro-L. So far so good, he is starting to get back to his obnoxious self after only 2 weeks of taking the medication.

Susan M Verified Purchase
September 21, 2021

love this site ... takes just one minute to order !!

John D Verified Purchase
June 8, 2021

Really works well on our horses.

Rachel t Verified Purchase
May 3, 2021

Does what it is supposed to do!

Deb D Verified Purchase
April 26, 2021

This product was prescribed by my Vet. My mini horse has EMS, and Thyro-L has corrected the issue. It worked within 24 hours and now I have a happy , healthy , active mini horse. Would recommend this product to anyone who has the same issue with their horse. Allivet is a very reliable company, shipping is done in very good packaging, delivery is prompt. Would recommend Allivet to everyone who needs pet products. Thank you, Allivet!

Robert G Verified Purchase
April 26, 2021

Allivet is always quick and easy and their prices are great

DEBBIE L Verified Purchase
April 26, 2021

Great prices and fast shipping

Pamelia H Verified Purchase
April 26, 2021

Vet recommended for elevated insulin levels.

Diane P Verified Purchase
February 23, 2021

This product has been maintaining my horse’s Cushings disease. No complaints.

Stacy j Verified Purchase
November 10, 2020

I like that I can have this sent to me at anytime, Allivet has the products that I need

Marie D Verified Purchase
November 10, 2020

good product

DEBORAH N Verified Purchase
August 28, 2020

My pony lives on this and the shipping is quick!

PAMELA E Verified Purchase
August 10, 2020

Great price on my horse meds.

Catherine V Verified Purchase
July 31, 2020

Great buy

Kelly E Verified Purchase
January 28, 2020

Much less expensive than any other on-line pharmacy.

Rosemarie W Verified Purchase
January 20, 2020

Great price and fast service!

Mary J Verified Purchase
November 6, 2019

Best price anywhere and they email you tracking info so you know exactly where your order is and when it will arrive.

April N Verified Purchase
October 25, 2019

I have a automatic ship on my Thryol for my donkeys. Always arrives on time. I get the best price,too. They have a super customer service department. Wouldn’t buy anywhere else!

Susan C Verified Purchase
September 17, 2019

Great service and prices

Lynn C Verified Purchase
September 17, 2019

My horse has metabolic disease and this was recommended by my vet.

Susan L Verified Purchase
August 15, 2019

This product is helping my mare to lose weight and she's become more energetic as well!

Maryanne S Verified Purchase
July 31, 2019

This is for an older labrador retriever with weight issues.

Susan L Verified Purchase
July 15, 2019

My vet recommended it, I order other products from Allivet as well. I trust them.

Denise v Verified Purchase
July 10, 2019

Prompt and Reliable

Allison G Verified Purchase
July 8, 2019

My horse has to have for thyroid so my vet wants him on it. He has been on it for a few days i see a difference in him.

Sheila H Verified Purchase
July 2, 2019

Convenient to use and excellent service.

Nancy C Verified Purchase
April 22, 2019

Easy ordering and good price

Sharon d Verified Purchase
April 15, 2019

Thyroid supplement that was recommended by my vet for my senior Haflinger mare. She eats this powdered medication in a small amount of feed with no problem. It has helped her lose her excess body fat.

Janice A Verified Purchase
March 26, 2019

Easy service to use

Jacki O Verified Purchase
March 11, 2019

Best value on the market. Speedy reply, follow up and delivery.

Linda T Verified Purchase
January 25, 2019

Seems to be working well

Brigitte B Verified Purchase
December 6, 2018

So easy to buy and the best pricing out there!

Nancy C Verified Purchase
November 12, 2018

Recomended by my vet

Diana D Verified Purchase
November 2, 2018

Product works great.

Linda s Verified Purchase
October 22, 2018

good price easy free shopping

Nancy A Verified Purchase
October 15, 2018

FAST SHIPPING AND ABOUT HALF THE PRICE OF VET CHARGES.

Jodi S Verified Purchase
August 22, 2018

daily RX for horse - medicine is cheaper than purchase at vet office

James G Verified Purchase
July 23, 2018

It has kept my aging horse very comfortable and sometimes a little spunky.

Mary K Verified Purchase
May 29, 2018

My horse has more energy and has lost weight. Very effective product.

Nancy C Verified Purchase
May 7, 2018

Vet recommended

CHRISTY S Verified Purchase
April 30, 2018

I have had my IR/Cushings horse on this since he was diagnosed. His thyroid is fine, but this has been helping him with weight loss since he was overweight when diagnosed. This has worked amazingly well.

Mary J Verified Purchase
March 5, 2018

My vet has me use Thyro-L occasionally on my pony to help boost her metabolism for weight loss.

Victoria W Verified Purchase
November 29, 2017

Great product for my easy keeper mare. $9 less than at the vet's office. Thanks Allivet.

Kira B Verified Purchase
August 30, 2017

Phenomenal product!

Lori P Verified Purchase
August 30, 2017

They really keep in contact with your vet and they send it quickly. Way cheaper than buying it at the vets.

Darah S Verified Purchase
March 1, 2017

This product has worked for my mare. She is getting her energy back and losing weight.

Arlene F Verified Purchase
December 14, 2016

This was prescribed by my vet for my horse but found this to be cheaper here than thru my local source.

Blanca C Verified Purchase
October 27, 2016

This stuff is helping my plump gelding loose some weight! :)

Claire G Verified Purchase
August 18, 2016

Always great for international orders

Sheila H Verified Purchase
August 11, 2016

Very happy with this product and the service was efficient, easy and quick!

Cindy P Verified Purchase
August 4, 2016

My order arrived quickly, and it was nice that Allivet emailed me when they requested the prescription from my vet. That way I was able to know when to call my vet to be sure that they responded to the request promptly.

Brenda L Verified Purchase
July 13, 2016

Great product ,fast shipping

Jan W Verified Purchase
June 17, 2016

My 20 y/o TB gelding had lost weight and muscle mass even though I had drastically increased his pellets and offered excellent quality free choice hay. After a few months on THYRO L he looks like a young horse again. Allivet is a very efficient and cost conscious company. Thank you for excellent service!

Keith C Verified Purchase
May 24, 2016

This and Metformin (Diabetic horse) have made our horse's life much better.

Danette N Verified Purchase
April 26, 2016

This was my 1st time using Allivet and it won't be my last. Customer Service was great. Placing my order was easy and receiving the item was fast.

DEBRA B Verified Purchase
April 7, 2016

Good for metabolic mini mare

Carolyn P Verified Purchase
January 26, 2016

The medication is good but more of a delay than I had hoped for in receiving he medication. I am still waiting; although, we have had a snowstorm - I thought it would have been here prior to the storm.

Michelle M Verified Purchase
October 18, 2015

Works great but needs to have some flavor to disguise the taste. After a while my horse does not want to eat the grain that has Thyro-L mixed in with it.

Michelle M Verified Purchase
October 18, 2015

Works great but needs to have some flavor to disguise the taste. After a while my horse does not want to eat the grain that has Thyro-L mixed in with it.

Lisa D Verified Purchase
April 29, 2015

Thyro-L has my horse from founder for 4 years, and helps maintain his healthy weight!

Katherine S Verified Purchase
April 28, 2015

Great product! Really gives my horse the energy he needs.

Virginia F Verified Purchase
April 10, 2015

Great product and price. Good service.

Janet M Verified Purchase
February 25, 2015

My two insulin resistant horses are on Thyro-L. I but the giant size and keep in the freg.

TERI L Verified Purchase
January 16, 2015

2 Show horses were having problems with their thyroid and this helped.

Sandy E Verified Purchase
April 17, 2014

I am very grateful that i can buy this product from Allivet for a reasonable price. Definitely cost less than at the vet's office. It's a great value and the shipping is speedy. I'm very happy with this product and service!

Questions & Answers