Why has my The Ordinary vitamin C serum changed colour?

Which vitamin C formula do you have?

Ascorbic acid and L ascorbic acid are names for pure vitamin C. Ascorbyl glucoside and tetrahexyldecyl ascorbate are derivatives used in different The Ordinary formulas.234

The vitamin C derivatives in these two products convert into vitamin C in the skin. The water free format of Ascorbyl Tetraisopalmitate Solution supports the derivative's stability. That makes the formula relevant to your decision, rather than treating every vitamin C bottle as interchangeable. Match the name and ingredient list on your box, because The Ordinary updates formulas and lists can differ by purchase date and region.24

Can you keep using a changed bottle?

Do not use another brand's colour chart as a pass or fail test for The Ordinary. SkinCeuticals' pure vitamin C serums can range from clear to light yellow or light brown, and its formulas retain potency despite colour changes. Those are different products. Colour is not a laboratory result, even when the bottle looks determined to provide one. For your changed bottle, ask The Ordinary to check the exact product and describe its original colour, current colour and storage conditions before deciding whether to continue.1

How can you limit further colour changes?

These are general vitamin C storage steps, not a way to restore a changed serum.

1. 1Move the bottle to a cool, dark place away from direct sunlight and heat.
2. 2Close the bottle tightly after every use to limit air exposure.
3. 3Record when you opened the bottle and check its own label for storage and use instructions.

Vitamin C products can lose effectiveness over time. About six months is a general lifespan estimate, not an expiry date for every The Ordinary formula. Protecting vitamin C from light matters too: opaque or dark packaging reduces exposure, while a clear bottle offers less protection.6

How should you use a suitable bottle?

Once the bottle's condition is settled, follow that product's directions. The Ordinary tells you to apply a few drops of Ascorbyl Tetraisopalmitate Solution morning and evening, avoid the eye area, use only on unbroken skin and use sun protection during the day. Its compatibility instructions say not to use it with niacinamide. For Multi Antioxidant Radiance Serum, apply morning and evening with fingers or a cotton pad, avoiding the eye area; its listed conflicts are peptides, copper peptides and GF 15% Solution.24

General vitamin C routine guidance places serum after cleansing and toner, before moisturizer and morning sunscreen. Visible benefits take about three months, so an immediate change in the liquid's colour is not a measure of progress on your skin.36

What should make you stop?

Vitamin C can cause dryness, itching or redness. The Ordinary advises patch testing: apply a small amount to clean skin on the upper forearm, keep it dry and rinse after 24 hours unless another duration is specified. Do not use the product if redness, burning, itching, blistering or irritation occurs. For irritation from Ascorbyl Tetraisopalmitate Solution, rinse it off, stop using it and consult a physician.234