Updating this thread to add that OutSmart has been pulled from the market. The product page currently says:
“OutSmart Fly Spray is currently unavailable
We’ve received tons of positive feedback about OutSmart from horse owners across the country since its launch. While we’re thrilled it is working so well for so many, we’ve also heard reports of skin sensitivity occurring in a small percentage of the horses it was used on. Because we stand for healthy horses and happy riders, even this low incidence rate has us pausing to evaluate the formula, making it even better for horses and the riders who love them.”
My friend told me this after her horse had a bad reaction to it. He is a calm 28-year-old who became agitated, ran around, ground his teeth, shook his head, and yawned repeatedly after application. He settled down once rinsed off but has lingering skin issues. She called SmartPak and they issued her a refund and told her that they were pulling OutSmart from the market because so many people have had issues with it.