I have been taking Hydrolyzed Collagen myself because I am almost 50 and my body ached. I had read numerous articles stating how Collagen is amazing for the human body because at about 30 or so the human body stops making its own collagen so a person would need to supplement themselves to have continued nail growth, less wrinkles, less body and joint aches etc - So last Novemeber I started taking 11 grams or 1 scoop daily and in 2 weeks I noticed a real difference in my body aches. My nails grow like crazy and my skin looks better than it has in the last 10 years!
SO, I happen to have a gelding that has a suspensory injury. I had him on smart tendon, but then heard about Equinity which is basically amino acids - but no collagen. I purchased some so I could see the label and try it out - but also started giving my gelding Hydrolyzed collagen thinking he would have the same benefits from the amino acids and collagen that I am having…guess what? He is moving better. The healing is also coming along too and I have noticed less head bob at the trot. I now have all FIVE of my horses on 1 scoop or 11 grams of collagen. Its more than anything Smartpak has to offer. Their highest level of collagen in their product is 5000mg. Thats 1/2 of 1 scoop of human grade collagen. I have read several studies on collagen for horses and they suggest that it even helps ulcer healing. Here are some article for your enjoyment. =)
https://theequinereport.com/2017/11/hydrolyzed-collagen-a-supplement-to-maintain-stomach-health/
http://www.thehorse.com/articles/25568/collagen-shown-more-effective-for-arthritic-horses