I just recently purchased my 3rd set of these studs. I have both ears triple pierced and these are the standard earrings I wear most everyday and usually even sleep in. They have never caused an allergic reaction and hold up really well. Most people probably wouldn't wear them as much as I do and each set has lasted for a year or so before the base of them darkens and I need a new set. I would give them 5 stars if they didn't do that!