I used Equine Herbals E-mmunity (think it is a James Hart product) for my horse when he was recovering from a virus and hepatitis - used 2 bottles over 3 months on the advice of Catherine at Naturally Animals. It did help my boy, but I can't help with Sarcoids im afraid!
Might be worth giving Naturally Animlas a call, they are very helpful
We have recently used Thuja on 2 horses with sarcoids. One was a small relatively new one and it was gone in 3 weeks. The other was the size of a golfball and we had tried sarcX and some topical treatments. We fed thuja 4 times a day for 3 months and it is completely gone. We noticed a difference straight away and then bits started budding off until the whole thing fell off. I would really recommend it. We got it directly from helios. We tried to feed at least 4 times a day, which is annoying, but less might work too
I never fed any supplements for my boys sarcoids, just made sure he was well fed with a balanced diet and it seemed to work! He had liverpool cream treatment for one lot and iridium wire for the other
I used SarcEx on one of mine & within a couple of month it dropped off. I decided there was no harm in trying it as the sarcoid was in an awkward place & as she was a nervous mare I didn't want to go down the Liverpool cream route. So glad I didn't now!