Cat therapy

Our cat (age unknown) has been looking pretty manky since winter. Some home remedies and a bit of TLC doesn't seem to have made much difference so today I took him to the vet. I should probably mention here that he's a very odd cats with lots of little quirks and 'normal' doesn't apply.

Vet asked lots of questions. I was on a deadline so rushed through the answers and rudely interrupted her. She probably thought I was on speed. Anyway, the outcome was that the vet agreed cat looked a bit manky and wanted me to spend $267 on blood tests to find out why. I wasn't keen on the idea of working 10 hours to get an answer and suggested we explore some other possibilities.

Vet said cat could be stressed. We discussed some scenarios and decided to treat the condition as if anxiety was the cause and if there was no improvement, we'd go ahead with the blood tests. Vet then said that if the blood test were negative for anything, her best guess would be stress and there's an injection she can give cat but she can't give it unless the blood tests are negative.

Fair enough. But what I want to know is, if there's an injection for cats that will apparently chill them out and also encourage soft, shiny fur growth, why in the name of modern miracles isn't it being developed for humans? We know that stress is a major cause of modern health issues - this sounds like answer. And who wouldn't want soft, shiny fur, erm, hair?
If there are any drug companies reading this, I put my hand up to be guinea pig. Or cat, as the case may be.