Are garlic and onion mosquito repellent or attracts mosquitoes?

Garlic, citronella, and other "odorants" are not as effective as DEET repellent sprays (e.g. Off products), which actually mask what attracts mosquitos: the scent of lactic acid and the CO2 you exhale. Mosquitoes will home in on both. An oily repellent product is not much more effective than a non-oily one, because the bugs will find unprotected areas.