Latherin in horse sweat makes it foamy.


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



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


Latherin creates the foamy sweat


  • 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 there are sweat and friction going on.


When your horse sweats, he is cooled as 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. Again, it’s not a sign that your horse is overworked. It’s actually a really good sign – and you know that when you see latherin your horse’s own cooling system is working.


  • Now don’t panic if you have never seen it on your horse – that doesn’t mean your horse’s sweating system is “broken”, it very likely means that there’s no friction on the sweat.


  • 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.

You can easily rinse sweat and latherin from your horse after a workout. You can also sponge or wipe it 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.



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!


Simple and affordable grooming tool!




Thanks, everyone!