Reviewed by Dr M Ajmal Iqbal, MBBS, MTI Medical (Pvt.) Ltd — Last updated: May 2026
This article is for informational purposes. Consult a dermatologist for persistent pigmentation.
Vitamin C serum reduces skin pigmentation through two mechanisms: it inhibits tyrosinase (the enzyme that drives melanin production) and neutralises UV-triggered free radicals that initiate melanin overproduction in the first place. Used correctly, it is one of the most evidence-supported brightening actives available. Most users in Pakistan apply it at the wrong step, pair it with incompatible ingredients, or continue using an oxidised product that has lost bioactivity. This guide covers the correct application protocol, what to pair with vitamin C, and how to prevent oxidation in Pakistan's warm climate. Laskee's Gluto-C Serum combines pharmaceutical-grade L-glutathione with vitamin C in a single stable formula — formulated by MTI Medical (Pvt.) Ltd, a Lahore-based pharmaceutical manufacturer where both actives are produced to pharmaceutical-grade standards and the combination is stabilised in airless, opaque packaging to prevent degradation.
Key Takeaways
- Apply vitamin C serum after cleansing, on clean skin, before moisturiser and SPF — always in the morning
- Wait 60–90 seconds after application before layering other products
- Pair with glutathione for 30–40% faster results — vitamin C regenerates glutathione after it neutralises free radicals, and both inhibit tyrosinase through different pathways
- Discard if the serum turns orange or brown — oxidised vitamin C is inactive and cannot brighten skin
- In Pakistan's climate, store in a cool, dark place; refrigerate if possible; use within 3 months of opening
The Correct Application Order
Vitamin C is water-soluble and absorbs best directly on clean skin. Full routine order for morning:
- Cleanse — remove sunscreen, sebum, and pollution from the previous day/night
- Tone (if used) — balance pH
- Vitamin C serum — apply to dry or slightly damp skin, 2–3 drops for full face
- Wait 60–90 seconds — allow full absorption before the next step
- Moisturiser — seals in the active
- SPF 50+ — required as the final step; vitamin C and SPF together provide significantly better UV protection than SPF alone
Morning, not night. Vitamin C's antioxidant function protects skin from UV and pollution throughout the day.
Application Technique
Quantity: 2–3 drops for the full face. More product does not increase efficacy.
Method: Warm between fingertips, then press gently into skin. Do not rub. Rubbing drags product across the surface before absorption; pressing concentrates it where you apply.
New users: Start every other day for 2 weeks. Mild tingling for a few seconds is normal — ascorbic acid is formulated at low pH (around 3.5). Sustained burning or redness indicates sensitivity; reduce frequency or switch to a derivative form (ascorbyl glucoside is more stable and gentler).
How Vitamin C Actually Works on Pigmentation
Tyrosinase Inhibition
Vitamin C chelates the copper ion in tyrosinase's active site, reducing its catalytic activity. Less tyrosinase = less melanin produced at the dark spot source. This is the same mechanism that glutathione uses — but through a different binding pathway. Running both simultaneously blocks melanin production more completely than either alone.
Free Radical Neutralisation
UV radiation and pollution particles generate reactive oxygen species (ROS) in skin. These ROS directly signal melanocytes to increase melanin production. Vitamin C (ascorbic acid) neutralises these free radicals before they trigger the melanin cascade. For Pakistan's combination of high UV, pollution, and heat, this antioxidant function is as clinically relevant as the direct brightening effect.
The Best Pairing: Vitamin C + Glutathione
This combination consistently outperforms either ingredient alone, for a specific biochemical reason:
When vitamin C (ascorbic acid) neutralises a free radical, it is oxidised to dehydroascorbic acid — inactive. Glutathione acts as a direct regenerator of oxidised vitamin C, converting it back to active ascorbic acid. This means the combination maintains higher active vitamin C concentrations for longer in the skin.
The result: dual pathway tyrosinase inhibition + sustained antioxidant protection + glutathione-regenerated vitamin C. Clinical data suggests a 30–40% faster brightening timeline versus standalone vitamin C for dark spots.
This is the formulation logic behind Laskee's Gluto-C Serum — both actives combined in a single stable formula with pharmaceutical-grade glutathione from MTI Medical.
What to Pair Vitamin C With
Works well:
- Glutathione — biochemical synergy (as above)
- Niacinamide — complements vitamin C through a different mechanism; the claim that niacinamide “cancels” vitamin C has been debunked
- Hyaluronic acid — adds hydration without compromising vitamin C
- SPF — essential; vitamin C + sunscreen provides significantly better UV protection than SPF alone
Separate from vitamin C (different sessions):
- Retinol — use vitamin C in the morning, retinol at night; different pH requirements affect stability of both
- AHA/BHA acids — same session application can reduce vitamin C stability and increase irritation risk
- Benzoyl peroxide — can oxidise vitamin C, cancelling its antioxidant function
Signs Your Vitamin C Serum Has Gone Bad
Vitamin C (ascorbic acid) oxidises on contact with air, heat, and light. In Pakistan's warm climate, oxidation happens faster than in temperate countries.
| Sign | What It Means |
|---|---|
| Pale yellow → orange → brown | Progressive oxidation; orange/brown = inactive |
| Metallic or off smell | Degradation products |
| Cloudy or gummy texture | Breakdown of formula |
| No tingling (was present before) | Ascorbic acid fully degraded |
Storage rules: Keep in a cool, dark place. Refrigerate if possible. Use within 3 months of opening. Choose opaque, airless packaging — this is why Laskee's Gluto-C Serum uses this format specifically for Pakistan's climate.
Expected Timeline on Pigmentation
- Week 1–2: Skin looks more radiant; antioxidant effect is the fastest-acting benefit
- Week 4–6: Surface dark spots begin to fade; overall skin tone more even
- Week 8–12: Significant fading of post-acne marks and sun spots with daily use
Paired with glutathione, these timelines typically accelerate by 30–40% because the dual-mechanism approach reduces melanin production more completely.
Vitamin C Percentages: What to Look For
For L-ascorbic acid:
- Below 10%: Sub-therapeutic for brightening
- 10–20%: Effective range; 10–15% optimal for most skin types
- Above 20%: Higher irritation risk without proportionally better results
Derivative forms (ascorbyl glucoside, ascorbyl palmitate, sodium ascorbyl phosphate) are more stable but convert to active ascorbic acid more slowly. Appropriate for sensitive skin but slower results.
Frequently Asked Questions
Which vitamin C serum works best for pigmentation in Pakistan?
For pigmentation specifically, a serum combining vitamin C with glutathione delivers the strongest results — dual pathway tyrosinase inhibition blocks melanin production more completely than either alone. Laskee's Gluto-C Serum combines pharmaceutical-grade L-glutathione (from MTI Medical) with vitamin C in stable, opaque airless packaging — preventing the oxidation that renders most single-active vitamin C serums inactive before they are half-used.
Is vitamin C serum good for dark spots in Pakistan's climate?
Particularly well-suited. Pakistan's high UV intensity and pollution create elevated oxidative stress — precisely what vitamin C's antioxidant function counters. Daily morning use of a stable vitamin C serum with SPF 50 is one of the most effective protocols for both treating existing dark spots and preventing new ones.
What percentage of vitamin C should I look for?
For L-ascorbic acid: 10–20% is the effective range. Below 10% is generally sub-therapeutic; above 20% increases irritation without proportional benefit.
Why does vitamin C serum sting?
Ascorbic acid is formulated at low pH (approximately 3.5) to remain stable — this causes transient tingling. Brief tingling is normal for new users. Sustained burning signals sensitivity; reduce frequency or switch to a gentler derivative form.
Can I use vitamin C serum without SPF?
Vitamin C provides some antioxidant protection, but without SPF, UV continues triggering the melanin overproduction it is trying to reduce. The vitamin C + SPF combination consistently outperforms either alone. In Pakistan's high-UV environment, SPF 50 is the rate-limiting factor in how fast any brightening treatment works.
