Calcium Thioglycolate (Depilatory Agent) CAS 814-71-1

Calcium Thioglycolate – Low-Odor Depilatory Agent for Mild Hair Removal

Basic Information

• CAS Number: 814-71-1

• Molecular Formula: C₄H₆CaO₄S₂ (Ca(SCH₂COO)₂)

• Molecular Weight: 206.29 g/mol

• Appearance: White crystalline or granular powder

• Odor: Nearly odorless (free thiol groups are blocked)

• Density: 1.79 g/cm³

• Solubility: 4–6 g/L at 25°C; increases at pH >9

• Melting Point: >200°C (decomposes)

• Storage: Store in tightly sealed containers, protected from moisture and light

Overview
Calcium thioglycolate is the calcium salt of thioglycolic acid, primarily used as the active ingredient in low‑odor depilatory creams and lotions. Unlike sodium or potassium thioglycolate, the calcium salt offers a milder, more controlled reaction with keratin, making it suitable for sensitive skin formulations. Its high alkalinity (cream pH ~12) provides effective breakdown of disulfide bonds in keratin without releasing significant free mercaptan odor, resulting in a more pleasant user experience.

Mechanism of Action
Calcium thioglycolate reduces the disulfide (–S–S–) bonds in keratin, the structural protein of hair. This chemical cleavage weakens the hair shaft, allowing it to be easily wiped away. The calcium salt form provides a slower, more sustained reaction compared to alkali metal salts, which contributes to its mildness and reduced skin irritation.

Applications

• Cosmetics: Used as the active depilatory agent in hair removal creams, gels, and lotions (typically 2–6% w/w, combined with calcium hydroxide for pH adjustment).

• Industrial: Applied as a mild stripper for removing epoxy resins from metal surfaces; also used as a complexing agent for precipitating heavy metals from wastewater.

• Pharmaceutical: May be used in specialized dermatological preparations for hypertrichosis treatment.

Key Benefits

• Effective hair removal with minimal skin irritation.

• Low odor – pleasant user experience compared to other thioglycolates.

• Gentle on sensitive skin – slower, more controlled reaction.

• Biodegradable – readily breaks down in the environment (80% degradation in 28 days).

• Versatile – suitable for cosmetics, industrial cleaning, and water treatment.

• Safe when used at recommended concentrations.

Safety and Handling

• Oral LD₅₀ (rat): >2000 mg/kg – low acute toxicity.

• May cause mild to moderate skin irritation; use appropriate personal protective equipment (gloves, safety goggles) when handling.

• Avoid contact with strong oxidizers and acids.

• Store in a cool, dry place, away from direct sunlight and moisture.

• Shelf life: typically 24 months under recommended storage conditions.

Quality Assurance
Each batch is tested for purity, pH, and depilatory efficacy to ensure consistent quality.