Chemistry & ProductsQuestion 304 of 484

Compared with a thiol-based (ammonium thioglycolate) perm, a sulfite-based 'true acid' perm typically:

a.Has a near-neutral to slightly acidic pH and produces a softer, less aggressive curl
b.Has a higher pH and processes faster than thio waves
c.Uses sodium hydroxide as its reducing agent
d.Requires no neutralizer because no bonds are broken

Explanation

Sulfite (acid) waves use ammonium sulfite or bisulfite at a pH near 6.5 to 7. They swell the hair less than alkaline thio waves, so they create a softer curl and are gentler on porous or color-treated hair, though processing time is longer.

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