Vitamin C Under $30: Cosrx Triple C Lightning Liquid Review

Continuing on with my Vitamin C series, here's my review of the Cosrx Triple C Lightning liquid that I've used almost daily for 3 months. I finally finished it up last month at the end of June soo I'm here writing this post so I can finally toss the bottle (I had to keep it for photo reasons cause blogger priorities.)

The two other vitamin c serums I've reviewed here on the blog are the Dr. Dennis Gross and Drunk Elephant.

I received this serum as a PR gift from Sokoglam-- the bottle is white as opposed to their classic back because it's their 1-year anniversary bottle! The serum inside is exactly the same as the permanent one.

Price, size, & availability

$27.00 USD for 1.0 fl oz via Sokoglam

While Cosrx is a Korean brand, this product, in particular, was done in collaboration with Sokoglam's founder. Therefore I'm not sure of its availability in Korea/ elsewhere. The good thing is Sokoglam offers international shipping!


Aronia Melanocarpa fruit extract (Black Chokeberry), Ascorbic acid (Vitamin C), Butylene glycol, Sodium lactate, Licorice root extract, 1,2- Hexanediol, Pullulan, Sodium Hyaluronate, Cassia obtusifolia seed extract, Allantoin

Active Ingredients

Contains 20.5% pure vitamin C (ascorbic acid) and 72% black chokeberry; the serum has a pH of 3.

If you're a fellow skincare addict, you might be familiar with L-ascorbic acid aka OG vitamin C. There are a dozen different derivatives out there on the market at this time, but from my understanding, LAA is arguably the most effective form of vitamin C in skincare as it's naturally occurring in our skin so our bodies already have the mechanisms to process it.

With some vitamin C derivatives, our bodies have to convert it into LAA before we start reaping the benefits. So by utilizing products that use LAA, we're cutting out the middleman.

If you're curious about learning more about Vitamin C, this journal article provides an easy to read summary as does this Beauty Brains post (they also go more into some vitamin C derivatives.)

Note: the Sokoglam ingredients list says ascorbic acid not L-ascorbic acid, but I'm making the assumption because the only other form of ascorbic acid out there is D-ascorbic acid, which is useless for our needs.

Of course, there are some downsides to using LAA as well-- for one, it's pretty unstable and needs to be protected from heat + light. Often it's stabilized through the use of ferulic acid and Tocopherol (vitamin E) but this formula uses black chokeberry extract. Another issue with LAA is that it can be potentially irritating at high concentrations for those with sensitive skin. While other vit C derivatives might not provide as dramatic results, they may be a better (gentler) option if your skin cannot tolerate LAA.

What does it do?

This is a straight up vitamin C serum. There are a few hydrating and soothing ingredients but the start of the show is the LAA.

The real question is, what doesn't LAA do?? Vitamin C is a true powerhouse. She is the queen of multi-tasking. If you read the literature review I linked earlier in the post, you'll get a good overview of the various potential benefits.

To list the main ones: it works as an antioxidant and protects the skin from oxidative stress. It helps at fading hyperpigmentation. It has anti-inflammatory benefits that could aid with acne and rosacea. I should stress that these are all POTENTIAL benefits, not guarunteed outcomes. I'm no scientist but even I have the knowledge to say that there are too many unknown factors at play to say that every single LAA serum will deliver all these benefits to every user.

When do I use it?

Personally, I like using vitamin C serums in the morning because it can help protect against UV radiation (not that you should use it INSTEAD of sunscreen, rather as an additional step.) I'll apply it as the first step after washing my skin, as I do with all actives. From my experience, the earlier on in my routines I apply my actives, the better results I see. I've read on Reddit that applying actives after slapping on your toners and essences and all that jazz has the potential to decrease the serums' effectiveness because then they need to penetrate through other those layers of skincare. I'm not sure of the veracity of that statement but I follow it nonetheless because it doesn't hurt!

After applying the serum, I'll wait a few minutes for it to dry and then continue on with my routine, the last step being sunscreen, of course.

Personally, I was able to use it 4-5x times a week as my skin is pretty used to acids. If you have sensitive skin or have never tried a vitamin C serum before, I recommend easing yourself into it. Try it 2x a week and work yourself up to using it more frequently, checking if your skin becomes irritated or excessively dry along the way.


Quite watery, it's probably the thinnest Vitamin C product I've tried or seen to date. It absorbs very quickly UNLESS you over-apply. In that case, it leaves my skin a tad tacky. But even then because it's so lightweight, the tackiness disappears as you apply the rest of your skincare.


It doesn't really smell like much, which is uncommon for a vitamin C serum. They usually smell stinky or overly fragranced because of added scents. I *think* the reason this one doesn't stink is because it doesn't use the same Ferulic Acid + vitamin E combo that the stinky ones do.

Results & Review

HOLY SMOKES, Y'ALL!! I saw brightening results from using this serum after about a week and a half. My scars were significantly lighter which is very impressive because they usually take months to fade (#melaninproblems.) Personally, I did not experience any purging or sensitivity, but then again I've been a regular vitamin C user for over a year now so I wasn't expecting any.

It also helped keep my skin relatively smooth. I don't think I'll ever have invisible pores and baby smooth skin, but that doesn't mean I can't try. With regular use I saw less breakouts. Although when I stopped using an AHA at nighttime for a week and a half, I did see some milia popping back up. So while this does have a positive effect on my acne, it isn't enough to keep it 100% away.

The one major issue I had with this serum is how freakin' fast it oxidized!! All you really need to know about vitamin C oxidation is that your serum will turn darker (in this case from clear to a deep orange) and you won't receive as much/ if any of the benefits as it oxidizes. Within the first month this serum had gone from clear to a light yellow. At that point, I started keeping it in the fridge a few days a week but even that didn't stop it from fully oxidizing. By the time I stopped using the serum I had a few days use left, but I didn't see the point in using it because the color was so dark. I used it up on my chest to get it over with.

On one hand, I think it's cool that Sokoglam thought outside the box with their preservative system (chokeberry extract rather than the traditional ferulic acid + vit E), but I don't think it worked. SO MANY people messaged and commented on my posts about the serum on Instagram, saying that they also had issues with it oxidizing.

TLD;R version: I loved the results I saw from this serum but I hate how unstable of a product it is. While I am tempted to repurchase it, there are other options out there are similar price points that I want to try first (Timeless skincare, Mad Hippie, Paula's Choice, etc.)

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