Masking stinky Garlic Supplement?

My horse gets eaten alive on his sensitive belly area. I've already tried fly sheets, fly sprays, topical ointments, holistic remedies, you name it. Nothing has worked and he spends 6 months a year tortured by the itch. Garlic may have a downside, but if you search the internet long enough, you can find information to disprove the effectiveness of any supplement out there. For the sake of my horse's belly, I'll take my chances with a natural substance like garlic. I'll know in a month or so if it works, so no harm no foul if it doesn't. If you have any better suggestions, feel free to throw them out there. I'm all ears.

Feeding Garlic to Horses - benefits and dangers

Sorry to double post, but here's an already somewhat conflicting article. It suggests that the commercially produced garlic supplements destroy the ingredient that creates the anemia problem. If anything, I'd be more worried about my horse getting too much selenium (apparently it's high in garlic) than anemia.