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CALCIUM SULFATE.

Valuable CAS 7778-18-9 / ABRASIVE, BULKING, OPACIFYING

A multifunctional inorganic salt primarily utilized as a structural setting agent in professional modeling masks and as a mild abrasive in refining treatments. It serves as the framework for occlusive delivery systems, enhancing the transdermal absorption of accompanying active ingredients.

Abrasive Bulking agent Opacifier Viscosity controller Setting agent

Science

When utilized in hydrocolloid systems like modeling masks, calcium sulfate acts as a cross-linking catalyst that reacts with alginates to form a solidified, rubberized matrix. This reaction creates a therapeutic occlusive seal that temporarily elevates skin temperature and prevents transepidermal water loss, effectively forcing hydration and water-soluble actives into the stratum corneum. In powder formulations, its crystalline structure provides gentle physical exfoliation and oil-absorbing mattifying properties.


Research

High confidence
Effective range 10–20%
Optimal

15%

Key findings

  1. 01 Demonstrated a 45% increase in skin hydration levels post-application through the formation of an occlusive rubberized seal.
  2. 02 Classified as a mild irritant with a 0.41/4.00 patch test score, indicating high dermal tolerance in rinse-off applications.

Transparency

Not commonly dusted
Min. effective
10%
Red flag below
2%

In its primary role as a setting agent for modeling masks, concentrations below 10% are often insufficient to achieve the necessary chemical cross-linking for a functional 'rubber' seal. However, in powders or toothpastes, lower percentages are legitimate for texture and abrasion.


The Formula

Solubility
Water
Optimal pH 7 – 7.5
0 7 14

Stability

Exhibits retrograde solubility (solubility decreases as temperature rises) and is highly hygroscopic in anhydrous form, requiring airtight storage.

Synergies

  • Sodium Alginate
  • Diatomaceous Earth
  • Humectants (to be locked in by occlusion)

Conflicts

  • Metal tools
  • Amino acids
  • Peptides
  • Proteins
  • Tetracycline antibiotics

Safety

CIR Status
Safe as used
Max tested
20%
Pregnancy
Safe
Sensitization risk Low

Recognized as GRAS (Generally Recognized as Safe) by the FDA; it is a stable mineral compound with a long history of safe use in food and cosmetics.


Your Skin

Yes Normal
Yes Dry
Yes Oily
Yes Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Valuable

An essential structural component for professional-grade occlusive treatments that significantly boosts hydration and ingredient penetration.


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