I have never heard of it but I did a quick google and found out that it is plant based, ingredients include:
Instaid - - a proprietary blend of extracts of Frankincense, Citrus reticulata, Camelia sinensis and Curcuma longa standardized for organic acids, polymethoxylated flavones, catechins and curcuminoids.
Apparently Martha Stewart featured this product (woo hoo). The website also sold this formula specifically for people and horses. My own personal opinion is that I tend to like products that offer an equine version as I know 'horse people' have a completely different level of care for their animals (if you know any horse owners you'll know what I mean), again, its just my take on it. I'd try it if I had a need for it. I've helped my Timber with all sorts of herbs and holistic remedies. Just be sure to always read the contraindications.
my 2 cents,