Vitamin C (Ascorbic acid)

Vitamin C (Ascorbic Acid)

Vitamin C (ascorbic acid) is one of the most widely recognised cosmetic actives and is commonly used in formulations designed to support a brighter-looking complexion and more even skin tone. It is a popular choice in radiance-focused and age-support skincare, where fresh, potent vitamin C is desired.

Ascorbic acid is the pure, biologically active form of vitamin C, which is why it remains so highly regarded. However, this same potency also makes it one of the most challenging ingredients to formulate with successfully.

Notes on formulating with ascorbic acid

Ascorbic acid is highly sensitive to air, heat, and light, meaning it oxidises easily and can lose effectiveness if not carefully handled and stabilised. It requires a low pH environment, typically between pH 2.6 and 4.0, to remain active. This can limit its compatibility with some formulations and may not be suitable for very sensitive skin.

Creating a stable vitamin C serum at home can be difficult without controlled formulation conditions and appropriate stabilisation strategies. Many DIY formulations have a relatively short shelf life, and visible yellowing or browning is a common sign that oxidation has occurred.

For this reason, ascorbic acid is best suited to fresh, small-batch formulations where it can be used promptly and stored carefully.

Considering alternatives?

If you’re looking for a gentler or more formulation-friendly option, we also stock vitamin C derivatives that are significantly easier to work with and offer greater stability:

• Ascorbyl Glucoside – A stable, water-soluble vitamin C derivative suitable for serums, gels, and creams

• Tetrahexyldecyl Ascorbate – An oil-soluble, premium vitamin C derivative ideal for facial oils and anhydrous serums

Both options have a longer shelf life and are generally better tolerated than pure ascorbic acid.

Formulation tips

• Store airtight and protected from light to help slow oxidation
• Best used in low pH, water-based serums
• Adding chelators (such as sodium phytate) or antioxidants (such as vitamin E) can help support stability
• Avoid heating, as heat accelerates oxidation

Common Name: Ascorbic Acid, Vitamin C

INCI: Ascorbic Acid
Certification: Conventional
Appearance: Fine white powder
Origin: China
Solubility: Water soluble
Usage Rate: 1 to 10 percent
pH Range: 2.6 to 4
Vegan: Yes
Palm Oil: No
Animal Tested: No

All our products are for external use only.