Vitamin C Serum in Pakistan: How to Choose, Use and Store It
Vitamin C (L-ascorbic acid) is an antioxidant used on skin for photoageing and hyperpigmentation, but a dermatology review notes that it is unstable and difficult to deliver. Light exposure oxidises it to dehydroascorbic acid, which turns a serum yellow, and an acidic pH below 3.5 helps stability. Choose protective packaging, store it away from light, and discard a serum that has darkened.
Key takeaways
- Vitamin C is used topically for photoageing and hyperpigmentation, but it is unstable.
- Light oxidises L-ascorbic acid to dehydroascorbic acid, which turns serum yellow.
- An acidic pH (below 3.5) helps stability, which is one reason these serums can sting.
- We found no source proving that heat specifically degrades it, so we make no claim about Pakistan’s heat; keep it away from light and heat as a sensible precaution.
What does vitamin C do on skin?
Vitamin C is a potent antioxidant that can be used topically to treat and prevent changes associated with photoageing, and it can also be used for hyperpigmentation. It is part of the skin’s own antioxidant defences, and UV exposure reduces the vitamin C available in skin. It does not replace sunscreen.
Why does a vitamin C serum turn yellow?
L-ascorbic acid is unstable. When it is exposed to light it oxidises to dehydroascorbic acid, and the serum turns yellow. Researchers are working on more stable forms and better delivery for exactly this reason. A yellow or brown serum has partly oxidised, so it may be less useful and, if your skin reacts to it, less comfortable.
| What you see | What it suggests | What to do |
|---|---|---|
| Clear or pale serum | Not noticeably oxidised | Keep using; store carefully |
| Yellow serum | Oxidation has started | Replace soon |
| Dark orange or brown serum | Substantially oxidised | Stop using and replace |
How do you choose a vitamin C serum?
- Packaging: opaque, airtight packaging such as an airless pump reduces light and air exposure.
- Printed form and strength: L-ascorbic acid or a named derivative, with a percentage.
- Fragrance and other actives: keep it simple if your skin is sensitive.
- Size: a smaller bottle you finish quickly is better than a large one that oxidises.
- Seller: buy from an authorised seller to avoid old stock.
How should you store and use it?
| Do | Avoid |
|---|---|
| Keep it in its box, in a cool, dark place | Leaving it on a sunny shelf or in a hot car |
| Close the cap tightly after each use | Dipping fingers repeatedly into an open jar |
| Apply to clean, dry skin, then moisturizer | Layering several actives at once |
| Use sunscreen every morning | Relying on vitamin C instead of sunscreen |
How does vitamin C compare with other brightening serums?
| Ingredient | What we can say |
|---|---|
| Vitamin C | Antioxidant used for photoageing and hyperpigmentation; unstable in formulations (Telang, 2013) |
| Tranexamic acid | Small trials of 3% topical tranexamic acid in melasma; see tranexamic acid serum |
| Kojic acid | Widely used; we make no research claim; see kojic vs tranexamic acid |
| Combined serum | A 12-week study of 3% tranexamic acid, 1% kojic acid and 5% niacinamide reported improvement in pigmentation problems |
Chelure does not sell a vitamin C serum. Our Brightening & Anti-Aging Serum uses 3% tranexamic acid, 3% kojic acid, AHAs and alpha arbutin instead.
How do you introduce a vitamin C serum?
- Patch test behind the ear for 48 hours.
- Apply a few drops to clean, dry skin once a day.
- Follow with a light moisturizer and, in the morning, sunscreen.
- Keep other actives on different nights while you are starting.
- Stop if you have burning, swelling or lasting redness.
What does a simple routine look like?
| Step | Morning | Night |
|---|---|---|
| Cleanse | Gentle cleanser | Gentle cleanser |
| Treat | Vitamin C serum, if you use it | A different active on alternate nights |
| Moisturize | Light gel | Light gel |
| Protect | Broad-spectrum sunscreen SPF 30+ | None |
What mistakes make vitamin C serums fail?
- Buying a large bottle you cannot finish before it oxidises.
- Storing it on a sunny shelf.
- Using a serum that has turned dark.
- Layering several actives with it.
- Expecting it to replace sunscreen.
How do you compare value?
Divide the price by the size in mL, check the printed form and strength, and factor in how fast you will use it, because an oxidised serum is wasted money. A smaller, well-sealed bottle you finish within weeks is often better value than a bigger one.
Frequently asked questions
Why has my vitamin C serum turned yellow?
L-ascorbic acid oxidises to dehydroascorbic acid on exposure to light, which turns a serum yellow. A darker colour means more oxidation.
Is a yellow vitamin C serum harmful?
It is likely less effective, and if your skin stings or reacts, stop and replace it. See a doctor for a lasting reaction.
Can I use vitamin C in the morning and night?
Many people use it in the morning under sunscreen. Introduce one active at a time.
Can I use vitamin C with tranexamic acid or niacinamide?
We have not summarised evidence on combining them. A simple approach is to use them at different times of day and introduce them one at a time.
Does heat damage vitamin C serum?
The review we cite describes light as the oxidising factor and does not address heat, so we make no claim. Keep it in a cool, dark place anyway.
Does vitamin C replace sunscreen?
No. Daily broad-spectrum sunscreen is still essential.
Can I use vitamin C every day?
Many people do once their skin tolerates it. Start slowly and watch for irritation.
Does vitamin C cause breakouts?
Some people report new bumps with a new product. Patch test and introduce it alone.
Is vitamin C better than tranexamic acid?
They are different ingredients with different evidence, and we do not claim either is better. See our tranexamic acid guide.
Sources
- Telang PS. Vitamin C in dermatology. Indian Dermatol Online J, 2013;4(2):143-146. doi:10.4103/2229-5178.110593 (PubMed 23741676)
- Desai S, Ayres E, Bak H, et al. Effect of a tranexamic acid, kojic acid, and niacinamide containing serum on facial dyschromia: a clinical evaluation. J Drugs Dermatol, 2019;18(5):454-459 (PubMed 31141852).
- American Academy of Dermatology. Sunscreen FAQs
A gentle reminder
Skincare helps the look and feel of your skin; it does not treat medical conditions. Patch test any new product behind the ear or on the inner arm first, and introduce one new active at a time. If you are pregnant or breastfeeding, or you have a skin condition such as eczema, ask your doctor before adding active ingredients. See our FAQ for more, or build your own routine.
Related reading: How to choose a serum for dark spots.