*BESTSELLER* Vitamin C Serum with 20% Pure Vitamin C
FRESH DROP: Now shipping fresh batches bottled on July 13, 2026.
Because Vitamin C works best when it’s the FRESHEST.
Dermatologist-Tested for Sensitive Skin (Dermatest® Excellent Rating for Skin Tolerability)
Meet our Bestselling Collagen Booster, Vitamin C Serum!
- A lightweight but hydrating oil-free serum.
- Formulated with 20% Pure Vitamin C, L-ascorbic acid, the purest form of vitamin C, at pH level of below 3.5 for MAXIMUM PENETRATION, allowing vitamin C to work from WITHIN to visibly brighten the skin and even out skin tone
- Allantoin to carry active ingredients into the skin for MAXIMUM RESULTS
- Hyaluronic acid and panthenol (Vitamin B5) to hydrate the skin and replenish skin barrier for healthier skin.
Click here to find out why Dr. Louie developed Vitamin C Serum.
Certified for Your Peace of Mind:
- EWG Verified® for the highest standard of ingredient safety and transparency.
- Certified by The Vegan Society, ensuring our formula is cruelty-free and contains no animal-derived ingredients.
Before/After Pictures
- Visible improvement in the look of redness, reduced look of inflammation, and overall brighter skin
- Visibly reduced appearance of hyperpigment
SAMPLE WITH ORDER
- Two potent antioxidants for maximum benefits: Formulated not only with 20% of L-ascorbic acid at an optimal pH level of 3.2 but also with another strong brightening agent, Emblica Extracts, for enhanced brightening effects and protection against skin aging caused by free radicals
- Strengthens weakened skin barrier: Provitamin B5 (panthenol) and Aloe extract soothe irritated and sensitive skin while strengthening the skin barrier.
- Gives long-lasting hydration: Hyaluronic acid and plant-derived glycerin draw moisture and lock it in to keep the skin hydrated, keeping skin plump and health.
- Works in synergy with All-in-One Essence for enhanced antiaging effects: L-ascorbic acid in this product and Emblica(R) in All-in-One Essence work in synergy to deliver enhanced antiaging and brightening benefits.
PUREST form of Naturally-Occuring Vitamin-C (L-Ascorbic Acid) 20%
Clinically-proven antioxidant that gets absorbed quickly into the skin to protect the skin from free radical damage
Hyaluronic Acid
Draws moisture from the surrounding to give the skin a long-lasting hydration
Panthenol
Regenerates the skin while strengthening the skin barrier
Emblica Extracts:The patented 200 x concentrated Indian Gooseberries, Emblica, high in pure Vitamin C. A strong antioxidant, age-defying, and brightening agent
AQUA, ASCORBIC ACID, GLYCERIN, PANTHENOL, ALLANTOIN, HYALURONIC ACID, ARGININE, CAPRYLYL GLYCOL, PHYLLANTHUS EMBLICA FRUIT EXTRACT, ALOE BARBADENSIS LEAF JUICE
After washing your face, dab in 3-4 drops per cheek. Wait a few minutes until the liquid is fully absorbed and the skin feels tacky to the touch rather than wet. Once the serum has settled and your skin feels firm and slightly grippy, apply Revitalizing All-in-One Essence to lock in the nutrients.
For best results, keep the product at around 15℃.
*Because of the special nature of ascorbic acid, the product may change colour to brown after opening. As such, we recommend using the product within 3 months.
Our Recommendation
- For Collagen Boosting: Use with All-in-One Essence
- For Sensitive Skin: Use every other day (at night) to make sure your skin gets used to ascorbic acid
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Frequently Asked Questions
Who Is It For?
Our Vitamin C Serum is for anyone who wants a powerful product that is still gentle on the skin. It is perfect for:
- Sensitive Skin: Dermatest® "Excellent" rated on Sensitive Skin and formulated with high levels of skin-soothing ingredients like Panthenol and Allantoin to mitigate the irritation often associated with pure Vitamin C.
- Wrinkles & Collagen Support: To address fine lines and keep your skin firm
- Brightening & dark spots: Specifically formulated for those with hyperpigment, dullness and uneven skin tone
- Antioxidant Protection: Excellent antioxidant protection against free radicals and environmental stressors that cause premature aging.
- Those seeking an EWG Verified and The Vegan Society Certified
Absolutely! We use a high concentration of panthenol and allantoin to soothe and reduce irritation that often comes with a high concentration of pure vitamin c.
You can apply it first at night time, every other day to make sure your skin gets used to Vitamin C. Then you can slowly increase frequency.
Yes, you can use our Vitamin C serum if you're pregnant or nursing. However, skin can become more sensitive during this time, so we recommend doing a patch test before full use to ensure compatibility. As always, consult with your healthcare provider for personalized advice.
Yes, our Vitamin C Serum is gluten-free.
How To Use
To get the most out of our Vitamin C Serum:
- Application: Apply 3-4 drops per cheek to a clean face.
- Technique: Dab the serum into the skin. Dabbing preserves the low-pH environment needed for the Vitamin C to work from within, whereas rubbing can sometimes cause unnecessary friction on sensitive skin.
- Routine: Use it as your first active step. Wait a few minutes for Vitamin C Serum to fully absorb. If using in the morning, follow with its best friend, All-in-One Essence, and an SPF (like our Protection Cream) to double your defense against UV damage. To get the best out of Vitamin C Serum, we recommend using it twice a day, morning and night.
You can use it both morning and night.
Just make sure to cover it with SPF, like our Protection Cream, when you use it in the morning.
We generally recommend 4-5 drops per cheek, but it all depends on how much moisture you need. Just DAB it in, instead of rubbing it in.
You can use Vitamin C Serum both morning and night. Dark Spot Serum is for night time. Your routine would generally be like this:
Morning
1) On clean face, apply Vitamin C Serum all over, followed by our All-in-One Essence or a moisturizer of your choice.
Night
1) On clean face, apply Dark Spot Serum on areas where you have dark spots, age spots, and visible wrinkles.
2) Apply Vitamin C Serum all over, followed by our All-in-One Essence or a moisturizer of your choice.
If you have SENSITIVE skin, then use Vitamin C Serum in the morning, and Dark Spot Serum at night.
Yes — you can layer this serum with your other treatments. A typical routine could be:
Morning: Vitamin C Serum → All-in-One Essence of your Choice → SPF
Night: Dark Spot Serum on target areas → Vitamin C Serum→ All-in-One Essence of your Choice
This sequencing helps protect and treat without reducing effectiveness.
Sensation & Tolerance
You don't have to keep it in the refrigerator. If you have a wine cooler, you can keep it there for freshness, but it's not a must. As for stinging, yes. We use a high concentration of L-ascorbic acid, and for its stability, penetration, and effectiveness, the pH level is kept low. So when you first apply it, it'll sting a bit. As long as it does not turn bright red, it's completely fine. And as your skin gets used to it, it won't sting :)
A slight stinging at first can happen because L-ascorbic acid is formulated at a lower pH to improve skin penetration and effectiveness. This should lessen as your skin gets used to it.
Vitamin C can be powerful on its own. Some actives may increase irritation when used together; many dermatologists recommend using vitamin C at a different time of day than exfoliating acids, benzoyl peroxide, or retinoids to avoid potential irritation. Always observe your skin’s response and adjust.
Results, Care & Formula Integrity
Vitamin C Serum should be clear to yellow. But if it turns bright orange to brown, stop using it as it has oxidized and lost its effectiveness.
As a general rule of thumb, try to finish using Vitamin C Serum within 3 months of opening. When not opened, please keep it in the refrigerator until you open it for use.
They work as a team. Vitamin C Serum (20% L-ascorbic acid) is a clinical-strength treatment for deep hyperpigment and wrinkles. The Essence uses Emblica® for surface-level protection and deep hydration. Using them together gives you faster, more visible results. When Emblica® neutralizes a free radical, it doesn't stop working; it transforms into a new antioxidant, which then transforms into another, creating a chain reaction of protection. This makes it stay active on the skin for a much longer period.
Vitamin C generally shows visible improvement in brightness and tone over weeks, especially with consistent daily use. Meaningful changes in texture or pigment may take 8–12+ weeks.
The Self-Preservation System is a patented formulation approach developed by Dr. Louie Kim to help maintain product stability and hygiene without relying on traditional preservative systems. It works through formulation design and ingredient synergy that create conditions less favourable for microbial growth, alongside controlled manufacturing and packaging practices. Products using this system are still assessed for safety and stability in accordance with applicable cosmetic regulations; the system describes the preservation approach rather than replacing required safety testing.
Dedicated to Brilliance: In-Depth Vitamin C Serum Insights
Winter Snow and the Hidden Danger of UV Rays – Why You Need Vitamin C Serum Now
Did you know that Vitamin C Serum is more important in winter when snow is abound than summer? It's because of the "hidden dangers" of UV rays during winter. Click to find out more!
Read more
Everything You Wanted to Know about Vitamin C Serum
One of the most frequently asked questions about Vitamin C Serum is when the BEST time it is to use Vitamin C Serum. Is it morning or night? Let's find out.
Read more
When is the Best Time to Use Vitamin C Serum: Morning or Night?
One of the most frequently asked questions about Vitamin C Serum is when the BEST time it is to use Vitamin C Serum. Is it morning or night? Let's find out.
Read moreCustomers praised this serum for its effectiveness on sensitive skin, with many reporting a healthy glow, reduced hyperpigmentation, and even skin tone. The fresh, non-irritating formula absorbs quickly and helps with dark spots and fine lines. Some found it slightly sticky or runny, and one noted bottle design concerns.
- My face has a healthy glow and it has really helped with my hyperpigmentation
- My skin is dewey and bright and I don't even feel the need for lotion
- My skin tone is more even, circulation seems better, and overall my skin looks healthier
So far I really like this product. I have a user error that maybe could be remedied with a different bottle type. As I was holding the open bottle in one hand and the dropper in the other, I accidentally poured a lot of the product in the open bottle out. Maybe a different kind of dispenser would be helpful?
Amazing product , the product is so absorbing and works so fine
I could feel the skin being brighter especially for the tan areas , it’s really boosting and makes skin healthier from dull looking face
No reactions for me so far as well
It gets absorbed so quickly
Sunscreen is a must for any products
I have sensitive skin and this vitamin C serum doesn’t irritate my skin. My skin looks brighter and clear and feels hydrated. I use it in the morning and evening and follow up with the oil free serum. Simple and effective routine. I am on my 4th bottle and just about to reorder.
I waited for 3 weeks to see the effect on my skin. So far no irritation and no breakouts (my skin is very sensitive). My face has a healthy glow with it and it has really helped with my hyperpigmentation so far. I’m going to keep using it for this healthy glow. The ingredients are safe and amazing and i’m seeing the results - that’s all i wanted in a product.
Nice to know that it is always fresh! No bad smell. It soaks in nicely and I like knowing it helps build collagen. It also helps even out my skin tone.
This serum goes on smooth and really helps even my skin tone and refreshes my whole face.
I’m sure this is good, but it leaves my face very sticky. It’s not a nice feeling.
I love that this is EWG verified. Our skin is our largest organ so thank you to Dr Louie for providing us with a serum that works to keep my skin revitalized deep down and in a healthy way!
This is a very nice C serum. The product I received was also very fresh, which I very much appreciate.
Just started using Vitamin C serum two weeks ago. I have sensitive skin and I haven't experienced any irritation at all and I am currently using am/pm. I like how my skin feels, it’s not sticky like some vitamin C products I have used in the past. I haven’t been using for long so I can’t comment on changes in my skin’s appearance, hence my 4 star rating. I do recommend this product!
I absolutely love and will repurchase!
I recently started using the serum and already my complexion appears brighter and smoother with a more even tone. There was some tingling initially, but it has now disappeared.
I recently purchased the vitamin c serum and it’s amazing! It definitely allows you to walk around with glowy skin while it’s on + very hydrating
My skin is veeery sensitive and these products have caused no reaction. I love the smell, they feel fresh and high quality. Thank you so much for creating clean products that work!
After reading the quality and science behind this product, I felt confident in trying it, and my face has never felt better! My skin is dewey and bright and I don't even feel the need for lotion because my face feels moisturized enough compared with before, my face would feel like a desert without a ton of lotion or oil applied to it. I will continue using this product hopefully forever.
As a functional medicine practitioner and someone recovering from chronic illness, I'm always on the search for high-quality, low-toxicity, and effective products. I found Dr. Louie on the EWG app, and given that he is EWG approved, I tried the products. I really love them! They're gentle on the skin, and I notice they give my skin a glow and healthy appearance. I also feel assured knowing these are organic and good for my skin, body, and world!
It works
Have been using for about a week and am surprised to already be noticing improvement in redness/little bumps on my chin that I've had for years. My skin looks healthier.
Absolutely LOVE this product!
I appreciate how nicely this serum absorbs into the skin with just a handful of drops. It’s too soon to say if I can see visible results, but I am pleased with the application on my skin and I appreciate the scientific principles behind this skin care line.
What I liked about this serum is that it has clean ingredients and is in a dark colored bottle (I think that is to preserve the active C). I think I saw a difference in my skin. What I didn't like it that it seemed very runny and didn't last long. I might have used too much? All that being said I am ordering again because I do think it made a difference. Love other products by Dr. Louie. (Hair growth)
I did a lot of research looking for an EWG-approved Vitamin C that also doesn't oxidize quickly AND feels great on the skin. This serum is absolutely the best I've tried. I notice a big difference since I started using it. My skin is softer and more radiant when I use it regularly. "Radiant" is hard to describe but I guess I would say, my skin tone is more even, circulation seems better (brighter skin), and overall my skin looks healthier. I also have confidence that the Vit C is fighting free radicals throughout the day. I had a little snafu with one of my orders and their customer support team was amazing. They made it right and even sent a free bottle as an apology for the trouble, which was not necessary but an amazing gesture. This is a great product and a really nice company as well. Win-win.
After an extended search for a clean, effective vitamin C serum, I can confidently state that this product has exceeded my expectations. Since incorporating it into my skincare regimen, I have observed a noticeable improvement in the brightness, radiance, and overall health of my complexion. My skin appears more dewy and vibrant, and I frequently receive compliments.
One of the most significant benefits I have experienced is the visible reduction in the appearance of hyperpigmented areas, which now appear less pronounced. As someone with oily combination skin that is occasionally prone to acne, I have found the formulation to be lightweight and non-comedogenic. It does not exacerbate breakouts or contribute to congestion.
While the product can leave a slight sheen on the skin post-application, this has not been a deterrent in my experience. Overall, I am satisfied with the performance and results of this serum and would recommend it to individuals seeking a clean, efficacious vitamin C product.
This serum makes my skin feel so smooth and vibrant! I mix it into my daily moisturizer and it makes a big difference. I Love it!
I have tried many brands of vitamin C since it is an important step to optimize healthy skin. Dr Louie’s is the best- it seems much fresher and my skin feels/ looks great when using it!
I have been using this for about a week now. I'm already starting to see a difference. I could not say enough about this product. Especially because it's EWG approved.
I have used this product for 5 years now and I truly love it. It has evened out my skin and minimizes my hyperpigmentations. My skin still looks fairly youthful at the age of 45. It’s a definite must in my morning and night skin routine.
This c serum really seems to help my skin. Buying again
Is vitamin c serum suppose to be used every day, year round?
Yes, Vitamin C is a Daily Essential!
For a radiant and firm complexion, we recommend using our Vitamin C serum every day, year-round. To get the best results from our specific formula, please follow these steps:
How to Use:
- The Routine: After washing your face, dab 4-5 drops per cheek.
- Layering: Use it before applying the Revitalizing All-in-One Essence for maximum collagen boosting.
- Sensitive Skin: If you are new to Vitamin C, start by using it every other day at night until your skin adjusts.
Vitamin C Serum isn't just for summer; it protects your skin from daily pollution and UV damage every single day, regardless of the season!
All Things Vitamin C
Learn more about our research and expert tips on Vitamin C, in particular L-ascorbic acid.
Winter Snow and the Hidden Danger of UV Rays – Why You Need Vitamin C Serum Now
Did you know that Vitamin C Serum is more important in winter when snow is abound than summer? It's because of the "hidden dangers" of UV rays during winter. Click to find out more!
Read moreEverything You Wanted to Know about Vitamin C Serum
One of the most frequently asked questions about Vitamin C Serum is when the BEST time it is to use Vitamin C Serum. Is it morning or night? Let's find out.
Read moreWhen is the Best Time to Use Vitamin C Serum: Morning or Night?
One of the most frequently asked questions about Vitamin C Serum is when the BEST time it is to use Vitamin C Serum. Is it morning or night? Let's find out.
Read more