Don't know what it is, but it's not the platelets. Mosquitoes don't know you have that. My wife and I are like candy to mosquitoes, while our neighbors sit outside in our mosquito infested part of the country without a bite. We'll never know why. I have to wear insect repellent and long pants in the heat and humidity while my neighbor does it in shorts and no shirt. We'll never know why. Some say they like sugar, but carbon dioxide seems to the their main thing. Mosquitoes are bad fliers with not a whole lot of genetic gifts other than survival. I've found, by the way, that concentrated lemon eucalyptus, a different repellent, works pretty well, and there's another one as well if deet isn't your cup of tea. They're all toxic to an extent, because they have to be to work. The natural ones don't work well or very long. Also, instead of spraying, try using the lotion, it allows for more exact application, but if anything really worked mosquitoes would all be extinct, right? They adapt.
Sorry, meant to say I do the yardwork in long pants etc.