Draft of bill aims to curb underage use of concentrated THC, set potency cap in Colorado Supporters, opponents, share views regarding highly concentrated THC A REPRESENTATIVE FROM THORNTON -- WHO ALSO HAPPENS TO BE A PEDIATRICIAN -- IS SPONSORING A BILL THAT AIMS TO KEEP CANNABIS OUT OF UNDERAGE HANDS.... BUT TO DO SO, THE BILL, IN IT'S CURRENT FORM -- SETS A POTENCY CAP ON MARIJUANA PRODUCTS ACTIVE INGREDIENT -- CALLED T-H-C. and last updated 2021-02-17 14:13:07-05 SOUTHERN COLORADO â A bill that has not been finalized yet is already making waves throughout the cannabis community in Colorado. The proposed legislation, that is still being revised, aims to reduce underage use of highly concentrated THC products. As the language reads at the time of this writing, it would also cap THC potency at 15% for both medicinal and recreational marijuana products.