Sodium Metabisulfite (Na2S2O5) is an inorganic compound widely utilized in the skincare and cosmetic industry for its preservative and antioxidant properties. This white or yellowish-white crystalline powder plays a crucial role in maintaining the integrity, stability, and safety of skincare products.

In skincare formulations, Sodium Metabisulfite functions primarily as an antioxidant, helping to protect the products from oxidation, which can cause deterioration of active ingredients, discoloration, and a reduction in product effectiveness. By preventing these oxidative processes, Sodium Metabisulfite extends the shelf life of products and ensures that their beneficial properties remain potent and effective over time.

Additionally, as a preservative, it helps to inhibit the growth of microbes and bacteria in products, especially those containing water. This is essential for ensuring the safety and hygiene of skincare products, as microbial contamination can lead to skin irritations, infections, and spoilage of the product. Sodium Metabisulfite’s role in preventing microbial growth makes it a valuable ingredient in creams, lotions, serums, and other personal care items.

Despite its beneficial uses in skincare formulations, Sodium Metabisulfite can be a concern for individuals with sensitive skin or sulfite allergies. In some cases, it may cause allergic reactions or skin irritation, particularly in those who are sensitive to sulfites. Therefore, its inclusion in skincare products is carefully regulated and monitored to ensure safe concentration levels that are unlikely to cause adverse reactions in most users.

Manufacturers and formulators of skincare products are also required to list Sodium Metabisulfite on product labels, allowing consumers to make informed choices, especially those with known sensitivities. As with any skincare ingredient, it is recommended to perform a patch test before using a new product extensively, particularly if you have sensitive skin or allergies.

In summary, Sodium Metabisulfite is a key ingredient in the skincare industry, valued for its antioxidant and preservative qualities that help enhance product stability, longevity, and safety. Its careful use within regulated limits ensures that skincare products remain effective and safe for a wide audience, while mindful consideration is given to those with specific sensitivities.

Sodium Metabisulfite (Wikipedia)

Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na₂S₂O₅. The substance is sometimes referred to as disodium metabisulfite. It is used as a disinfectant, antioxidant, and preservative agent. When dissolved in water it forms sodium bisulfite.

Sodium metabisulfite

Names
Other names Sodium pyrosulfite Sodium disulfite
Identifiers
CAS Number	7681-57-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:114786 N
ChEMBL	ChEMBL2016976 N
ECHA InfoCard	100.028.794
EC Number	231-673-0
E number	E223 (preservatives)
PubChem CID	656671
RTECS number	UX8225000
UNII	4VON5FNS3C Y
CompTox Dashboard (EPA)	DTXSID0029684
InChI InChI=1S/2Na.H2O5S2/c;;1-6(2)7(3,4)5/h;;(H,1,2)(H,3,4,5)/q2*+1;/p-2
SMILES [O-]S(=O)S(=O)(=O)[O-].[Na+].[Na+]
Properties
Chemical formula	Na2S2O5
Molar mass	190.107 g/mol
Appearance	White to yellow powder
Odor	Faint SO2
Density	1.48 g/cm3
Melting point	170 °C (338 °F; 443 K) decomposition begins at 150 °C
Solubility in water	45.1 g/100 mL (0 °C) 65.3 g/100 mL (20 °C) 81.7 g 100 mL (100 °C)
Solubility	Very soluble in glycerol Slightly soluble in ethanol
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H318
Precautionary statements	P264, P270, P280, P301+P312, P305+P351+P338, P310, P330, P501
NFPA 704 (fire diamond)	2 0 1
NIOSH (US health exposure limits):
PEL (Permissible)	None
REL (Recommended)	TWA 5 mg/m3
IDLH (Immediate danger)	N.D.
Safety data sheet (SDS)	Mallinckrodt MSDS
Related compounds
Other anions	Sodium sulfite Sodium bisulfite
Other cations	Potassium metabisulfite
Related compounds	Sodium dithionite Sodium thiosulfate Sodium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references