Both my horses grew much thicker manes, tails, and forelocks when I added extra essential amino acids to their diet (Nutramino). My mare's diet lacked them, and my old gelding must not absorb EAA's well from other food sources because adding a pure source made a huge difference. My gelding's mane is actually pretty respectable at the moment, and it used to be so pathetic I'd just roach it off. His forelock is longer (albeit still short) and way thicker than it ever was before. You'll just be paying for expensive urine if your horse is not lacking them, but it's worth a double check to ensure his diet includes enough EAA's! Otherwise I use Eqyss products because they moisturize and are silicone free so won't promote breakage. I don't go crazy brushing out, and don't do prolonged neck covers. I tried all the products with Samson before though, and nothing made much of a difference until I fixed his diet.