Why do horses get foamy sweat?


A few notes to dispel a common myth about horses – a foamy horse is not indicative of an overworked horse. The foam on your sweaty horse results from the ingredients of your horse’s sweat – and it’s a pretty snazzy horse adaptation. So – let’s talk about latherin.


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Latherin creates the foamy sweat


  • Latherin is the reason that horses foam up while sweating. And contrary to popular belief, it’s not bad!


  • Getting technical: Latherin is a protein that’s also a non-glycosylated surfactant. 37% of latherin is hydrophobic.


  • Translated: Latherin is a protein that acts like soap. It’s slippery, and 37% of latherin contains ingredients that repel water.


  • Latherin is also found in your horse’s saliva, and it’s suggested that saliva is the original source of latherin. Latherin in the saliva helps your horse chew and digest dry forage. Somewhere along the line, horses decided that latherin is also a great idea to put into sweat.


  • The theory is that latherin became a part of horse sweat to facilitate evaporative cooling with a hairy coat.



Foam doesn’t mean the horse is overworked. It means sweat and friction are going on.


How sweat cools your horse


  • Your horse cools when the sweat evaporates.  But, his hair coat, even in summer, is a physical barrier and traps the sweat.


  • So, latherin acts to “slickify” the sweat so that evaporative cooling is effective.


  • The foam is produced when the soapy properties of latherin are rubbed. Just as your sponge will foam up as you start to wash the dishes, the same is true for your horse. Reins and butt cheeks and girths will foam up the sweat. You will tend to notice it more where there is friction involved.


  • Some horses get super soapy and foamy, others do not.  Foamy horses are not necessarily overworked. It’s actually a really good sign – and you know that when you see latherin your horse’s own cooling system is working.


  • For horses that don’t get foamy – there’s no reason to panic.  Perhaps your horse doesn’t have a lot of friction, or your horse doesn’t produce much latherin. 


  • However, if your horse doesn’t sweat at all, or only partially sweats, you may have a horse with anhidrosis or partial anhidrosis. This is an entirely different scenario that needs careful management and veterinary care.




A teeny, tiny patch of latherin-induced foam.


Grooming the horse after sweating


  • You can easily rinse sweat and latherin with water.  No shampoo needed.  In hot months, this is the fasted way to groom your horse after a ride. 


  • You can also sponge or wipe latherin and sweat away. A cactus cloth does wonders to remove crusty and dried sweat after your horse exercises. A quick buffing with a wadded up cactus cloth takes all of the dull away.


  • For horses that get a bit dirty and sweaty, the hose is great.  Or, use a no-rinse shampoo to help lift the sweat and dirt if the weather doesn’t allow for a bath.


Does your horse get foamy when he sweats?





If you need to pick up a fancy-dancy cactus cloth for regular grooming and bathing, here’s the place. As an Amazon Associate, I earn from qualifying purchases, which are not a penny more for you. I couldn’t be more grateful for your support!


HandsOn Gloves on horse_.jpg

HandsOn Grooming Gloves – also, use code PEG for some free shipping!

Farnam Apple Elite Electrolyte, 20 lbs



Electrolytes for horses


                                Paste electrolytes are an option, too, if your horse doesn’t want to eat them in feed.



Apple flavored electrolytes for horses 


This is an evaporative cooling blanket for horses

Another cooling blanket option for horses


Genuine Cactus Cloth – Natural – 18 X 16-1/2 Standard This is much better for stain removal and spreading natural oils around.

This cactus mitt may be easier to use than a cloth.  


I love Easy Out for touch-up stain removal!


Thanks, everyone!