Well... My old workplace used to make and sell retinol for cosmetics in 13% solutions. It went into a lot of cosmetics found on the market. Each of the 1 kg bottle sold for I think $2000 each. It was one of the few products we made where I had to give back the remaining sample for QC check. Almost everything else we made that got QCd and was left over went into the waste stream.
I don't think you would be able to get anything that would be formulators grade unless you have a manufacturers license or something like that because anything above a very small percent retinol is only available by prescription. I'm referring to retinol or tretinoin (the stuff in retin-a). I don't remember what form of retinol we used to make the solutions.