Quercetin and dihydroquercetin

Hello everyone, I wonder about the differences of these two supplements. I've heard about the toxicity and lower positive effects of quercetin in comparison with dihydroquercetin. Any thoghts?  Also my friends recommended me to buy dihydroquercetin extracted from Siberian Larch as it is the most quality and price wise, so as these grow only in Russia I'd like to know if anyone knows if there are differences in different types of dihydroquercetin? Thanks in advance.