Sodium ascorbyl phosphate

Sodium ascorbyl phosphate is the sodium salt of a phosphate ester of ascorbic acid (vitamin C). Adding the phosphate group makes it much more stable in water than pure ascorbic acid, so it is less likely to turn yellow or brown in a finished product.

• Formula: C6H6Na3O9P, molar mass about 322.05 g/mol
• CAS number: 66170-10-3
• Appearance: white to off-white powder
• Solubility: water soluble; not oil soluble

Azlok lists Vitamin C (Sodium Ascorbyl Phosphate) Powder as a cosmetic raw ingredient. The name doesn't state a pack size, so check the weight on the product page. It's not sold as a food supplement or for eating. See today's price per kg.

• Water-based serums and toners as an antioxidant ingredient
• Creams and lotions aimed at uneven-looking skin tone, often alongside niacinamide
• Rinse-off products such as face washes and toothpastes in some brands
• Formulas where pure ascorbic acid would be too unstable or too acidic

Formulators choose SAP over pure ascorbic acid mainly for practical reasons. Ascorbic acid needs a low pH and turns yellow quickly once mixed with water, so it is often sold as a powder to mix fresh. SAP stays usable for longer in a water-based product at a pH that is closer to neutral. The trade-off is that it is a different ingredient, so don't compare percentages one-for-one with ascorbic acid recipes.

SAP is commonly used at about 1–3% in leave-on products. Treat this as a typical range and follow your supplier's data sheet.

1. Dissolve the powder in part of the water phase, or in a little distilled water.
2. Add it at the cool-down stage, below about 40 °C.
3. Keep the finished product around pH 6–7; SAP is most stable at neutral to slightly alkaline pH and is not suited to low-pH serums.
4. Use distilled water and a chelating agent such as disodium EDTA or sodium phytate, as metal ions speed up breakdown.
5. Fill into opaque, airless or pump packaging.

Avoid breathing the dust and keep it out of your eyes. Wear gloves when weighing.

• Store the powder tightly closed in a cool, dry, dark place; moisture shortens its life.
• Keep away from children.
• Throw out finished products that change colour or smell.
• Label homemade jars with the date; most home formulators use water-based vitamin C products within about three months.

Patch test any homemade product on a small area of the inner arm for 24–48 hours before wider use. If you plan to sell finished cosmetics in India, they need to meet BIS standards and CDSCO cosmetic rules, so check those before you launch.

Because SAP is used at low levels and slowly picks up moisture, a small pack is the better buy for home formulators. Larger packs make sense for regular production; transfer working amounts into a small jar so the main pack stays sealed. For 25 kg and above, use bulk inquiry.