Hi
@AliOop I just did some searches again (I remember looking it up before using but since it was last year, I don’t remember what I found then.) in looking up the results I do recall that sodium bisulfate caught my attention because the chemical composition said it had less sulphuric elements, which made me think it would not smell as bad as the meta bisulfate.
Someone in this
photography forum post says that if you add metabisulfate to water, it becomes sodium bisulfate (since the oxygen molecules are then added). It is the second response by Peter.
That made me wonder if the usage rate of metabisulfate would apply to sodium bisulfate (which is up to 5% in cosmetic applications
according to this, look under Safety Profile subheader). However, I have not found anything specific for sodium bisulfite recommended usage rate in cosmetics. The
Wikipedia page only lists exposure limits of 8 hours in some concentration that I do not know how to translate into usage rate. In the end they just said they deemed it safe for cosmetic applications without specifying usage rate.
The material safety data sheet from soapgoods, which can be found under the documents tab
here, did not list any human skin exposure results (it seems they did not test in humans but reported in some rabbits it could cause skin irritation) but in the exposure limits they just said “none established.” (?)
To be safe I would probably use the a 25% dilution, 75% being water, and that should stay under the 1.25% ingestion limit even if using at same weight as fragrance (if 1 oz per lb of oils). Anyway, I realize perhaps this is more info that you asked. I wished there was a quick definite answer out there!
