Interesting. As women tend to combat vaginal dryness later in life, guidelines like these are especially needed there. Pretty sure you very easily fall into a vicious circle of lubing, ruining cells which produce any remaining lube -> lubing even more. I guess the bottom line is to buy water-based lubes with some sort of an organic "gel" source and avoid propylene glycol/tons of glycerine/detergets (though those are harder to detect by name).