Years ago, probably in the 1970s, I was invited to one of those sales parties where there was a demonstration of a breadmaker and they tried to sign people up for a regular supply of their flour and their 'special secret ingredient' that speeded up the process. The secret ingredient was vitamin C, but they didn't tell you that (or you would have known you didn't need to buy into their regular supply).
I didn't buy it anyway - a long rising improves the flavour of the bread.