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Moumoujus

NONOXYNOL-9.

Avoid CAS 14409-72-4; 26027-38-3(generic); 26571-11-9; 37205-87-1(generic); 68412-54-4; 9016-45-9(generic) / SURFACTANT - CLEANSING, SURFACTANT - EMULSIFYING

Nonoxynol-9 is a nonionic surfactant primarily utilized in cosmetic formulations for its emulsifying and cleansing properties. It functions by significantly reducing surface tension, which facilitates the stable blending of oil and water-based ingredients. This mechanism also supports the effective removal of impurities and enhances foaming in products.

Summary

Emulsifying Agent Cleansing Agent Foaming Agent

Science

Mechanism of Action

As a nonionic surfactant, Nonoxynol-9 effectively lowers the surface tension between immiscible phases, thereby promoting the formation and stability of emulsions. This action allows for the harmonious integration of oil and water components within a formulation. Furthermore, its surfactant capabilities contribute to robust foaming and efficient removal of dirt, oils, and other impurities from the skin and hair.

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Key findings

  1. 01 A 2% concentration of Nonoxynol-9, or its close analogue Nonoxynol-8.3, demonstrated sensitizing effects in patients with dermatitis.
  2. 02 While a related nonoxynol (Nonoxynol-2) showed no allergic contact dermatitis at 5% in normal volunteers, reactions were observed at 10%, indicating concentration-dependent irritation thresholds.
  3. 03 Vaginal applications of Nonoxynol-9 in spermicidal gels at concentrations ranging from 3.0% to 4% led to histological inflammation and deep epithelial disruption in a subset of users, with lesion incidence increasing with more frequent use.
  4. 04 Within the cosmetic industry, concentrations exceeding 2.5% are generally considered a 'red flag' for potential skin irritation and consumer adverse reactions.

Transparency

Dusting Analysis

Not commonly dusted
Red flag below
2.5%

Concentrations of Nonoxynol-9 above 2.5% are recognized within the cosmetic industry as a red flag for potential skin irritation and consumer reactions.

The Formula

Formulation

Solubility
Both
Optimal pH N/A
0 7 14

Conflicts

  • Latex products (e.g., condoms, cervical caps, diaphragms) unless specifically formulated to be compatible, as Nonoxynol-9 can weaken or compromise latex integrity.

Safety

Safety Profile

CIR Status
Safe with restrictions
Max tested
5%
Sensitization risk High

The CIR Expert Panel concluded that Nonoxynol-9 is safe for cosmetic use when formulated to be non-irritating and used within appropriate concentration limits, specifically up to 5% in leave-on products. However, clinical data indicates a high potential for irritation and sensitization; a 2% solution has been shown to sensitize dermatitis patients, and concentrations above 2.5% raise concerns for general skin irritation. While the FDA classified it as safe and effective for vaginal contraception, it explicitly notes that it can irritate the vagina and does not protect against sexually transmitted infections (STIs), potentially increasing transmission risk in that specific application.

Your Skin

Skin Compatibility

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

Our Assessment

Verdict

Avoid

Nonoxynol-9, while effective as a surfactant for emulsification and cleansing, presents a high risk of irritation and sensitization, particularly in sensitive individuals and at concentrations exceeding 2.5%, making it unsuitable for precision skincare formulations.

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