Roz Salt Scalp Scrub vs Custom Wavy Hair Shampoo Base: which is safer?
Roz Salt Scalp Scrub is our pick: better on PFAS and on the overall hazard picture.
Our pick
Credo Beauty
Roz Salt Scalp Scrub
PFAS grade
Excellent 100/100
Overall grade
Excellent 86/100
Verdict
Buy
Hazard flags
⚑ 2
Material
salt crystals, mineral-based scrub
Confidence
82%
PossibleFragrance allergens or undisclosed fragrance components
ReportedMechanical irritation from crystal size and shape
Function of Beauty
Custom Wavy Hair Shampoo Base
PFAS grade
Excellent 75/100
Overall grade
Good 63/100
Verdict
Buy
Hazard flags
⚑ 3
Material
aqueous surfactant shampoo base; no treated coating or water-repellent coating applied
Confidence
82%
Possible1,4-dioxane (surfactant contaminant)
PossibleFormaldehyde releasers (preservatives)
PossibleFragrance allergens
Where these two actually differ
- We flag Fragrance allergens or undisclosed fragrance components and Mechanical irritation from crystal size and shape on the Credo Beauty and not on the Function of Beauty.
- We flag 1,4-dioxane (surfactant contaminant), Formaldehyde releasers (preservatives) and Fragrance allergens on the Function of Beauty and not on the Credo Beauty.
- The Credo Beauty is salt crystals, mineral-based scrub where the Function of Beauty is aqueous surfactant shampoo base; no treated coating or DWR applied, which is most of the difference in these two grades.
- The gap is 25 points, wide enough that this is not a close call, and the Credo Beauty is the one to buy.
Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →
More shampoo: see the full ranking