DESCRIPTION: Activ‑Shield (INCI: Sodium Metabisulfite) is a multifunctional antioxidant and reducing agent designed to protect cosmetic formulations from oxidative degradation while supporting overall product stability. As a powerful oxygen scavenger, it helps maintain the integrity of sensitive actives—particularly those prone to oxidation such as ascorbic acid, botanical extracts, and natural pigments—by preventing color shifts, rancidity, and loss of efficacy. Its strong water solubility and rapid reactivity make it especially effective in aqueous systems where oxidative stress is most pronounced.
Beyond its formulation‑protective role, Activ‑Shield contributes to product longevity and sensory quality by minimizing oxidative reductions and preserving active freshness throughout shelf life. Its antimicrobial support and compatibility with chelators further enhance system robustness, making it a valuable component in serums, lotions, hair treatments, and any formulation requiring enhanced oxidative stability. With proper handling and pH control, Activ‑Shield delivers reliable, high‑performance protection that keeps cosmetic products looking and performing their best.
At no more than 0.2% used in cosmetics as a preservative, the CIR considers Sodium MetabisulfiTe as GRAS (Generally Regarded As Safe).
Key Formulation Considerations
- Water‑phase incorporation — Sodium metabisulfite is highly water‑soluble and must be added to the aqueous phase, ideally under controlled conditions to minimize premature oxidation.
- Oxygen‑sensitive handling — It degrades in the presence of air and moisture. Use airtight storage, nitrogen blanketing, or add it late in the process to preserve reducing activity.
- pH‑dependent stability — Most stable in acidic to mildly acidic systems (pH 3–6). At higher pH, it converts to sulfite/bisulfite and loses antioxidant strength.
- Chelator synergy — Works best with chelators (EDTA, GLDA) that bind metal ions which otherwise accelerate oxidation.
- Compatibility with Vitamin C — Excellent stabilizer for ascorbic acid and derivatives by preventing oxidative degradation.
- Heat sensitivity — Avoid prolonged heating above 40–50°C; high heat accelerates decomposition and SO₂ release.
- Odor masking — May release a faint sulfurous odor; fragrance or odor‑neutralizing ingredients may be required.
- Antioxidant–preservative dual role — Can reduce preservative load by contributing antimicrobial activity, but should not replace a full preservation system.
Formulation Contradictions & Incompatibilities
- Strong oxidizers — Incompatible with hydrogen peroxide, benzoyl peroxide, percarbonate, and other oxidizing agents; they neutralize each other.
- Nitrites — Can form nitrosamines in the presence of nitrites under acidic conditions — avoid this combination entirely.
- High‑pH systems — Loses reducing power and decomposes; not suitable for alkaline hair relaxers, soaps, or high‑pH cleansers.
- Metal contamination — Iron, copper, and other transition metals accelerate oxidation; always use chelators and avoid metal‑contaminated raw materials.
- Air‑exposed packaging — Avoid jars or permeable packaging; use airless pumps or low‑oxygen headspace.
- Fragrance components containing aldehydes — May react with aldehydes, reducing fragrance stability.
- Colorants sensitive to reduction — Can bleach or reduce certain dyes and natural pigments.
Practical Formulation Tips
- Use level: Typically 0.05–0.2% depending on antioxidant load required.
- Add during cool‑down to preserve activity.
- Pair with antioxidants like tocopherol for a multi‑phase protection system.
- Use in oxygen‑sensitive formulas such as Vitamin C serums and natural extracts.
APPLICATIONS: In water-in-oil formulas, for skincare and haircare, creams, lotions, conditioners, butters, serums, etc
FORMULATION GUIDELINE
INCI: Sodium Metabisulfte. Synonyms: Disodium disulfite, Disodium metabisulfite,
Solubility: Water
Use Rate: 0.1 – 0.2% (Do not add beyond 0.2% to prevent irritation)
Temperature Stability: Heat tolerant ≤80°C.
pH Stability: 3.0 – 7.0 (3.0 – 6.0 for optimal function)
Assay: 99%
Appearance: White to off-white powder.
Storage: Store in a cool, dark, and dry place
This is a cosmetic raw material and is meant for external use only in cosmetic formulations. As with all of our materials, it should not be taken internally. Treasure Actives is not responsible for product compatibility. We advise everyone to test ingredients for performance, compatibility, and safety prior to committing to larger quantities. Keep all products out of reach of children. For more information, please see our terms and conditions page.
