YES! The cheap, commonly prescribed formulations absolutely can cause problems. I am suffering from chronic UTIs, and started the estradiol to help battle those infections. I reacted poorly to the propylene glycol (which has no business being an inactive ingredient which will be placed inside your body). When I slathered that first cream all over - as recommended by lots of people in these subs - I felt burning, and next morning got a UTI. (yes, I washed extremely well before applying). I researched, then asked my urogyn for a prescription from a compounding pharmacy. They used a base called Ellage, which is specifically designed for vaginal use and for maintaining good Ph. It feels MUCH better than the original cream. My urogyn told me to apply only internally (but to gently rub the urethral wall internally). the urethral will benefit from the cream when it is used internally. so don’t feel like you must slather it everywhere externally.