I keep hearing that here, but when I've used products containing sodium hydroxide (NTM Silk Touch leave-in, the re-formulated Yes To Cucumbers leave-in), I get bundle shedding rather than the few single strands I get when wet bunning which I do 99% of the time. The sodium hydroxide seems to be a common denominator so I'm erring on the side of caution.
I think it's also a ph balancer as well. But it's so down the list and in such a little amount that it won't affect the hair. YTC has it in some of their products as well.