Long Term use of Thyro-L?

I have a gelding that my Vet put on Thyro-L after a bout of laminitis. She recommends that we keep him on it permanently. I love my Vet, but I come from the show horse world, where they kept them on it, just to try and keep their necks slimmed down.

He also hates it, and I have to syringe it into his unhappy mouth.

Any thoughts or experiences?


My mini had a Near-Founder Experience last May & vet prescribed L-Thyroxine (Thyro-L).
I get it in powdered form & top-dress feed. He has no problem eating it this way.
& has been symptom-free since starting it.
AFAIK, he will be on it for life - not a huge expense & worth it to keep him sound.

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I am always learning new things here on COTH. I have never heard this one before.

My horse is on the powdered version because she came off the winter looking pregnant, and she eats it in her food no problem! If your horse really will be on it for life then maybe see if you can get the powder.

I have also never heard of using it to keep a neck slimmed down for shows lol.

What reason did the vet give?

What was the cause of the laminitis?

is the horse tested IR?

what’s his weight, or what was it before the Thyro-L?

My friends hackney pony has been on it for 3ish years to help manage his thyroid issue, so he will be on it rest of his life.

What does your horses blood work say? And what are you mixing it in when giving it? She mixes hers with molasses and applesauce. Pony mugs you to get his daily treat.

Yes, people use it for slimming necks and extra umph/energy in the big show world. I’ve used it for overweight ponies that are founder risk to get the weight off quicker.

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She said that she finds that Thyro-L helps to keep metabolic horses issues better under control, long term. No, he has not been tested. We’ve taken a bunch of weight off of him. He is leaner, at this point. I left him get chubbier over the winter, and then the hay man ran out of first cutting round bales, and brought out second. That pushed him right over the edge.

He is a rescue, owned by a rescue who will not pay anything toward his keep. I have been fostering he and his half brother for about five years. He is currently on pergolide, as well.

My pony has been on it for several years and it is beneficial. At first he would not eat it when sprinkled over his feed, but I got some inexpensive cherry jello powder at the grocery store and sprinkled a bit on top of the Thyrol-L. That did the trick and he ate it just fine. After a while I was able to eliminate the jello powder, but if you can’t, a fifty cent packet will last a very long time.


When my IR/EMS horse foundered way back when, he went on a high dose of Thyro-L to help with immediate weight loss. 4 tsp/day IIRC. Then as time went on, we did lower it gradually and he was on a maintenance dose of 1 tsp/day for a long time, but eventually we did wean him off. But he was under the care and supervision of the vet and had bloodwork all along for that. Never had an issue with him not eating it but being IR/EMS, he thought he was starving all the time and would have eaten a cardboard box. I only wanted to get him off it to see it would help behavior-wise (I’d read here about people saying it made their horses cuckoo), but it didn’t really make a difference with him.

He’s also on Previcox, although I should be able to wean him off of that soon. He will not touch the Thyrol-L, and his brother will eat anything, so I need to make sure I get it into him before they switch buckets. My blacksmith trimmed him, and his feet actually look pretty good right now. Good angles and concavity to his soles.

I have two of mine on it, but they go on in the spring after bloodwork and then off in the fall after more bloodwork. I also have them on Animed Remission and when mixed in with the small dose of grain and a bit of water, both of them eat it with no problem.

I’ve used Remission before, and I think that it is a great product. This guy used to run up for food, but since I changed him over to more beet pulp and ration balancer (Gro N Win) he is not as interested.

Well that’s pretty rude.


I had a horse that lived on Thyro-L with no ill effects but he also had blood work done which showed he had cushings and thyroid disease that needed treatment (he was also on Prascend). I don’t recall the blood work being much, maybe a couple hundred. I feel like that might set your mind at ease and would be good information to have.

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So the vet has prescribed Thyro-L and Pergolide, with no bloodwork being done? Did I read that correctly?

Yes, you did. Perhaps you can tell me what you can about the specifics of the testing.

It gets better. Last year, for my birthday I did a fundraiser on Facebook to try and raise money to have some different things done for the boys. I set it up so the money would go to the rescue. They kept the money and didn’t even reach out to me. I had emailed them to let them know that I was going to do it. Nothing. Crickets

:thinking: :astonished:

That’s insane to me.

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Good thing you rescued those horses from the rescue…


While I know vets use Thyro-L pretty liberally, and without doing bloodwork, I don’t know of any that would prescribe Prascend/Pergolide without it, add the Previcox and YIKES!!! Is this just the rescue medicating this horse with meds they have on hand? To answer your original question, yes, I have known of horses that live on Thyro-L for many years because of some sort of metabolic issue. The other meds you’ve mentioned, NO, not without periodic bloodwork to see what’s going on…

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