The Shreddies motto is ‘Fart with confidence’ according to their website, which says the "patented filter underwear removes odours through the use of a thin and flexible carbon cloth."
According to Mudhar, Shreddies get the job done.
"I wore Shreddies for three days around town and they seemed to work pretty well, although I wasn’t particularly gassy. Sure, I let a couple fly -- including one attempt on an elevator at work, which has mirrored walls, so I watched all the faces for familiar signs of putrid smell recognition, but no joy. Still, I needed to enlist another set of nostrils."
In the interest of science, Mudhar also enlisted the help of his wife.
“Back under the sheets in the Dutch oven, I let loose a few. One loud one and a couple of quieter follow-ups. Speaking scientifically, the problem with fart testing is that each one is a random occurrence, so you never know exactly what their stink level is going to be. There is no control group to compare it with. My wife inhales a big whiff and says: ‘I don’t smell anything.’ Success! The Shreddies seem to do what they say.”
UK-based Shreddies says their flatulence-filtering underwear "are a proven medical solution to flatulence," though they likely mean technological solution.