Sodium Thiosulfate
What is Sodium Thiosulfate?
Sodium thiosulfate (Na₂S₂O₃) is an inorganic compound, a sodium salt of thiosulfuric acid, typically produced through the reaction of sodium sulfite and sulfur dioxide. It forms colorless, water-soluble crystals without odor. Within cosmetics, it finds primary application in hair treatment products, especially permanent waving lotions and straightening formulations. Operating as a reducing agent, it targets the disulfide bridges in hair's keratin protein structure. By donating electrons, it cleaves these -S-S- bonds, softening the hair shaft for reconfiguration into curls or straight styles. Subsequent neutralization with an oxidizing agent, such as hydrogen peroxide, reforms the bonds in the desired shape, yielding durable results. This mechanism underpins professional chemical hair reshaping services, distinguishing it from temporary styling methods.
Roles in Formulation
This ingredient serves the following purposes in cosmetic formulations:
Benefits
Facilitates chemical reshaping of hair for lasting curls or waves.
Supports low comedogenic formulations suitable for pore-friendly products.
Aids in professional hair styling processes with a low hazard profile.
Who It's For
A quick guide for who this ingredient may suit (and who should be cautious).
| Who May Benefit | Who Should Avoid |
|---|---|
| People pursuing permanent hair curling or straightening treatments. | Those with sulfite sensitivities or allergies. |
| Users of salon-based chemical hair reshaping services. | Persons with highly damaged or porous hair shafts. |
| Individuals with hair responsive to disulfide bond modification. | People experiencing scalp dermatitis or open wounds. |
Safety Notes
- Recognized as safe for use in rinse-off hair products by cosmetic safety experts.
- Exhibits low overall hazard potential in standard applications.
Frequently Asked Questions about Sodium Thiosulfate
What role does sodium thiosulfate play in hair products?
It acts as a reducing agent in permanent waving lotions to break keratin disulfide bonds for reshaping.
Is sodium thiosulfate comedogenic?
It carries a rating of 0, indicating no pore-clogging tendency.
What is the safety profile of sodium thiosulfate?
It holds a low hazard rating and is deemed safe in cosmetic concentrations by review panels.