Has anyone tried CBD supplements for their horse?

My guy is a special case.... his whole history is TL;DR but essentially was locked in an 8x10 stall from age 1 to age 9, beaten, not fed, was up to his knees in poo and had never had his hooves or teeth cared for in his life. So he has some anxiety and anger issues. We love him anyway. He was rescued 6 years ago and I've owned him for 5. He shows First Level Dressage at rated shows and knocks the bred to perform horses out of the park.

He just has issues coming into spring. Call it Spring Fever, but every year its gotten a bit worse. This year was showing his beautiful rears every time someone tried to ask him to trot. His anxiety in the spring is super hightened (this horse is used to kids riding 4 wheelers all around him by now) and is reactive to literally everything. He got scared of the farrier dropping something out of his truck (25 feet away) last month and kicked me in the hip while he freaking out about it. 

I'm just wondering if anyone has used a CBD supplement for their horses! I have used it with my dog, who has anxiety, and it has helped calm him a bit. It's super expensive, so I don't want to just buy it for nothing. 

He's currently taking a magnesium supplement and doing a bit better on it.

bumping for you 

I don't know about CBD, as I've never used it on anything, but essential oils are great and I have used them with my horses and dogs and truly noticed a difference. 
https://cowgirlmagazine.com/essential-oils-anxious/