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Moumoujus

FERROUS SULFATE.

Avoid CAS 7720-78-7 / ASTRINGENT

Ferrous Sulfate is recognized for its astringent properties, designed to contract and tighten skin. However, its use in skincare is significantly limited by a notable potential for irritation, primarily due to the formation of sulfuric acid upon hydrolysis.

Summary

astringent

Science

Mechanism of Action

Ferrous sulfate acts as an astringent, facilitating the contraction and tightening of skin tissues. The observed potential for skin irritation is attributed to its hydrolysis, a process that yields sulfuric acid, which can be detrimental to the skin barrier.

Research

Clinical Evidence

Insufficient-data confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

The Formula

Formulation

Solubility
Water
Optimal pH 2 – 6
0 7 14

Stability

Aqueous solutions of ferrous sulfate exhibit optimal stability within a slightly acidic to neutral pH range of 2.0 to 6.0, with enhanced stability observed at lower pH levels, such as pH 2.0. This compound is highly susceptible to oxidation when exposed to air and moisture, transforming into ferric sulfate, with this degradation accelerated by higher pH, temperature, and light. For optimal preservation, storage in sealed containers between 2°C and 25°C in dry, well-ventilated environments is crucial to mitigate air and moisture exposure.

Conflicts

  • strong oxidizing agents
  • alkali materials
  • soluble carbonates (in neutral solution)
  • phosphates (in neutral solution)
  • oxalates (in neutral solution)

Safety

Safety Profile

CIR Status
Insufficient data
Sensitization risk High

While designated Generally Recognized As Safe (GRAS) by the FDA for oral food supplementation, ferrous sulfate's cosmetic application profile is restrictive. It has been delisted as a cosmetic color additive and is not approved for use in the eye area. Despite its recognition as an active ingredient in some OTC drug products, EU GHS Hazard Labeling Codes classify it as an irritant. Risks include potential skin and eye irritation, burns from mists, and documented instances of contact allergy characterized by redness, swelling, itching, and fluid-filled blisters upon patch testing.

Your Skin

Skin Compatibility

No Normal
No Dry
No Oily
No Sensitive
Irritancy High
Comedogenicity Unknown

Our Assessment

Verdict

Avoid

Due to its high irritancy potential, documented contact allergy risk, and restrictive regulatory status in cosmetics, Ferrous Sulfate is not recommended for precision skincare formulations despite its astringent properties.

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