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Vitamin C

Brightening Serum

3-O-Ethyl Ascorbic Acid (EAA) is a more stable, less irritating Vitamin C derivative that stays effective at a skin-friendly pH (~4-5), unlike L-Ascorbic Acid (LAA), which degrades quickly and requires a harshly low pH.

When paired with Ferulic Acid, EAA remains potent without rapid oxidation or irritation, delivering powerful antioxidant and brightening benefits—all while being gentler on sensitive skin.

Not at all! Tasmanian Pepper, a potent soothing ingredient from Australia, is one of the best for calming skin. We’ve added it to make Vitamin C gentler, even for sensitive skin—reducing redness, irritation, and sensitivity.

Absolutely. /PHD/'s Vitamin C Brightening Serum is made for all skin types and genders—including men. If your skin is more exposed to pollution and sun—Vitamin C helps by calming that damage, fading dark spots, and evening out the skin tone. Just follow it up with a moisturizer and sunscreen for best results.

Yes, you can use Vitamin C serum at night. While it’s popularly used in the morning for its antioxidant protection against sun and pollution, nighttime use is just as effective. At night, Vitamin C works to repair skin damage, support collagen production, and even out your skin tone while your skin is in recovery mode. Just avoid layering it with strong exfoliants or retinol unless advised by your dermatologist.

Vitamin C is prone to oxidation when exposed to air, heat, or light. To maintain its potency, store it in a cool, dark place and keep the lid tightly closed. If your serum changes colour (e.g., turns yellow or brown), it may have oxidized.

Great question — "antioxidant" is one of those skincare buzzwords that gets thrown around a lot but nobody really understands what it really means!

Antioxidants are ingredients that protect your skin from damage. Every day, your skin faces stress from things like sun, pollution, and even your phone screen — these create unstable molecules called free radicals that harm skin cells.

Think of free radicals as tiny troublemakers that break down collagen, speed up aging, and make your skin look dull.

Antioxidants are like your skin’s defense team — they stop this damage before it happens.

Ingredients like Vitamin C, Vitamin E, Ferulic Acid, and CoQ10 are powerful antioxidants that help keep your skin bright, firm, and healthy.

That’s a completely valid observation — and also a great opportunity to understand how skin science truly works. Dullness, pigmentation, uneven tone — these are often the result of months or even years of exposure to UV rays, pollution, oxidative stress, inflammation, and lifestyle factors like lack of sleep or diet. Because this damage runs deep, no dermatologist would ever promise visible results within a few days — especially for complex concerns like brightening or pigmentation. Here’s what a realistic, skin-aligned timeline looks like with consistent daily use:

Week 1–2: Your skin is adjusting to the actives. Vitamin C begins neutralizing free radicals and supporting collagen, while ingredients like Niacinamide and Betaine start calming inflammation and reinforcing the barrier. You may not see visible change yet — but the foundation is being laid.

Week 2–4: You may start noticing a subtle glow, more even tone, and slightly smoother texture. Your skin’s natural renewal process (about 28 days) is now in motion, and cell turnover starts to reveal fresher skin.

Week 4–6: Pigmentation begins to visibly fade, and dullness reduces. Skin appears noticeably brighter, more even, and resilient. Antioxidants and peptides continue to support long-term repair and protection.

Beyond Week 6: This is when the deeper benefits become evident — strengthened barrier, improved collagen function, and skin that looks more youthful, firm, and consistently radiant.

Remember, skincare is science — and at /PHD/, we don’t believe in quick fixes. We believe in long-term skin health, guided by clinical insight and honest timelines.

Great question—and let’s break it down scientifically.

Vitamin C doesn’t technically remove a tan, but it can help fade the appearance of it over time by:

- Inhibiting tyrosinase, the enzyme involved in melanin production

- Reducing oxidative stress, which contributes to skin darkening

- Promoting cell turnover, so pigmented cells get replaced faster

Since a tan is your skin’s natural response to UV exposure (melanin increase), Vitamin C can help brighten the skin and even out tone, making a tan fade faster.

For best results: Pair with daily broad-spectrum sunscreen—to prevent further tanning—and hydrating actives to support the skin barrier.

Yes, it is still safe to use. Ethyl Ascorbic Acid, the active ingredient in our Vitamin C serum, is a stable derivative of Vitamin C. However, like all Vitamin C derivatives, it can undergo slight colour changes due to environmental factors like light, temperature, and air exposure. If the serum changes from its original clear or light yellow hue to a deeper yellow or amber shade, it’s still safe to use and effective.

The serum is best used while it is still in its pale yellow to light amber state. Once it turns darker (brown or deeper amber), the stability and potency may be compromised. For best results, store it in a cool, dark place and tightly close the cap after each use.

Yes, this product is completely fragrance-free. What you may notice is a mild scent that comes from the active ingredients and the base formulation itself. We haven’t added any artificial or natural fragrance, nor have we included any ingredients to mask the base smell, so it remains as pure as possible. Sometimes, certain actives or carrier ingredients—like niacinamide or botanical extracts—can have a subtle inherent smell.

It’s possible you're experiencing purging, which is common when starting actives like Niacinamide, Retinol, Salicylic Acid or Vitamin C. This happens as the product speeds up cell turnover, bringing clogged pores to the surface usually in areas where you already get breakouts.

Purging typically lasts 2–4 weeks and then improves.
If breakouts appear in new areas or persist beyond 4–6 weeks, it may be irritation instead.

To support your skin:
– Keep the rest of your routine gentle
– Don’t introduce other new actives
– Use hydrating moisturizer and sunscreen

We’re here if you’d like help adjusting your routine!