soapfromthehip,
here is probably the best info i've found on shampoo bars and potential damage:
all about shampoo bars. it is by the same cosmetic chemist i mentioned earlier. on p. 2 of the article she discusses both hard water & pH being the culprits so i don't personally believe it is only about pH.
you can look up on these
hard water maps to get a general idea of how hard or soft your water is. here is
another map and they seem to agree generally but not completely. your state looks like one of the better ones for using shampoo bars. if you do decide to go ahead and use the shampoo bars here are some good tips i've come across:
• definitely use
the ACV rinse as it removes both buildup from oils, etc & mineral deposits from hard water & lowers the pH of your hair. i don't think this is optional at all from all my online reading
• use a showerhead filter or bottled water if you have hard water issues (ACV may well not be enough for some & personally i'd definitely do this if in a hard water area)
• consider the level of hard water in your area & the dryness or oiliness of your hair when determining what SF you use
• use a clarifying shampoo periodically if needed
• consider the porosity of your hair, if it is high porosity you may well have more problems because the cuticle is already more raised up
• lather the bar in your hands rather than directly on your hair to avoid breakage. i've read you need to lather really well & rinse really well too
• use a good conditioner after the ACV rinse if your hair needs it
• make sure any products you still use don't have silcones in them so you don't get silicone buildup which poo bars will have a harder time removing
• it may not be a good idea to use coconut oil as it's so cleansing, & possibly drying, but if you do keep it to a rather low %
• consider using
citric acid in your poo bar (interesting discussion about 3/4s of the way down in the comments about whether or not it can really lower the pH. soap queen says yes they got their bars, testing with pH meters, down to a pH of 7 after a year of experimenting on how to add the citric acid & still get a hard bar). this might well be another one of those things that really helps but i honestly don't know.
• consider your soap ingredients well for what is best for your hair & using poo bars & water type
• pay careful attention to the condition of your hair if you do use them. if noticing damage then stop using them or adjust your methods
so, shampoo bars are rather high maintenance and may not be the best way to clean hair, but maybe with a lot of tweaking they can work. some people do seem to have good results. i fully admit i am biased because i'd still like to try them so feel free to take everything i say with a big grain of salt. best.