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  • Writer's pictureNaya

All About Kiehl's Vitamin C Serum

kiehls powerful strength line reducing concentrate and eye brightening concentrate review

Kiehl's have introduced a revamped version of their bestselling Powerful-Strength Line-Reducing Concentrate and I figured that, as your trusted beauty enthusiast, I should take one for the team and see what the fuss is all about. If you are curious about this [very much hyped] skincare launch and whether it actually works or not, then please keep on scrolling!

Something new, Something old, Something bad

Now, it seems like everyone and their newborn puppy are on the Vitamin C bandwagon lately. Sure enough, homo sapiens have been benefiting from this miracle worker for what seems like centuries now, but it is this new wave of skincare technologies that offers us improved, powerful (and safe) solutions that we all get really excited about.

Although Vitamin C is kind of a big dog on the skincare block, if the formula is not well-thought-out, you might actually get a reversed effect (in other words temporarily botch your skin in one way or another). Ideally, Vitamin C products should improve skin tone, texture, elasticity, as well as reduce the look of fine lines and wrinkles. It is one of the best anti-ageing (and potent) ingredients out there, but if it is not formulated right, it will turn your skin into a pure kaka and believe me you - I am not talking about a New Zealand parrot here.

My Skin

Dry, dehydrated, sensitive.

The Serum

Kiehl's Vitamin C serum, better known as Powerful-Strength Line-Reducing Concentrate "Volume 2" , is the brand's newest blend that contains 12.5% Vitamin C plus Hyaluronic Acid (aka my bae). You also get not just one, but two types of your beloved ingredient here: 10.5% L-Ascorbic Acid (pure Vitamin C) and 2% Ascorbyl Glucoside (Vitamin Cg).

Claims: essentially Vitamin C skincare is packed with antioxidants, so it almost acts as a guard that protects your skin from free radicals and other environmental stressors (partially responsible for premature ageing). Extended use of products like this should improve your skin's overall quality and minimize the look of enlarged pores, scarring, hyperpigmentation and awaken your cells in a way that they are pushed to produce more collagen naturally.

kiehls powerful strength line reducing concentrate and eye brightening concentrate review

Packaging: Vitamin C products can go dark in colour due to air/light exposure; so it is nice to see a dark bottle with a pump here. Two important packaging bits that will not only protect your serum from the sun, but also ensure that your product preserves its power. You can also lock the pump, so that it doesn't leak if you choose to travel with your citrusy friend.

Texture & Application: a siliconey (Dimethicone is the second ingredient here), bone-coloured and smooth texture that gets nicely absorbed. Initially, you will feel a very sudden warm sensation on the skin, which actually means that the serum has been activated. If you have sensitive skin like I do, you might also notice a lovely flush on your cheeks, almost as if you have had a good jogging session. Powerful-Strength Line-Reducing Concentrate does have a very faint citrus scent, which might be explained by the fact that orange and lemon oils are part of this product's proprietary blend.

You can use this product twice a day, but if you are new to Vitamin C skincare, I would recommend going from one to two times a day in a week's time. Since Vitamin C additionally protects your skin from all the nasty UV rays, you can use a serum like this both day (underneath your favourite sunscreen) and night (underneath your moisturizer).

kiehls powerful strength line reducing concentrate and eye brightening concentrate review

First Impression: I am not going to lie, I was [freaking] scared about having an allergic reaction to this serum, mainly because I have experienced somewhat an intolerance to Vitamin C products before. My skin would get itchy and if I would decide to keep the product on for even a few hours, I would later find myself having incredibly dry, peeling skin that looked like a toxic amanita mushroom (very attractive, I know). All the drama aside, I am here to confess that Powerful-Strength Line-Reducing Concentrate is the only product of its kind that caused ZERO irritation whatsoever. And, on a side note, it was quite hydrating and yet semi-matte in finish, so it was easy to wear it under makeup. Skin felt smoother almost instantly and did not appear as tired-looking as before.

Prolonged Use: I was still getting a few hormonal breakouts here and there, but overall skin felt very supple, it looked much brighter and overall healthy. I felt like my post-breakout scarring disappeared much faster and thankfully I did not experience any extra bit of dryness, which is sometimes associated with products containing Vitamin C. My advice would be: don't neglect your favourite day or night cream while using this serum, even if you feel like this PH-neutral formula alone is enough for you. I believe that using my holy grail Ultra Facial Cream truly helped to lock in moisture and promote an overall well-balanced, hydrated look of the skin.

Now, luckily I don't have that many lines or wrinkles, so I can't really vouch for that part yet; but even with the results that I've got, I am positive that this formula does live up to its claims and in a long run will certainly improve an overall quality of your skin (especially if you are a beauty of a particular age, looking for safe ways to introduce anti-ageing products into your routine).

kiehls powerful strength line reducing concentrate and eye brightening concentrate review

The Eye Cream

Delicate skin under your eyes is an area you should never neglect and while I was testing Vitamin C serum, I have also been using the brand's Powerful-Strength Line-Reducing Eye-Brightening Concentrate. Just think about it as a baby version of the same product; one that is designed for under eye and has a slightly different formula (10.5% Pure Vitamin C plus Haloxyl).

Claims: noticeably decrease "crows feet", sub-orbital wrinkles and brighten eye area, while minimizing dark circles.

Texture & Application: lovely, siliconey texture that gets absorbed in a matter of seconds. Has a faint citrusy scent and light beige colour. Can be used both during your AM/PM skincare routine.

Now, I have to mention that I am very picky when it comes to eye creams; I have a very dry under eye situation going on (plus hereditary panda circles), so even with a myriad of eye lotions and potions I try every year for this blog, I can never find anything that works better for me than Creamy Eye Treatment With Avocado. At this point I have a feeling that my dark circles are not going anywhere, so to ensure that I don't further dry out and potentially age my under eye, I always opt for the same hydrating cream over and over again for what seems like 6+ years now. I might stray and cheat on my moisturizers and serums, but never on my eye cream.

My Experience: when I tried the brand's very own Vitamin C eye cream (one that has pretty much same wonderful claims as the serum we just chatted about) at first I really enjoyed it, but over the course of one-two weeks I started noticing just how dry my under eye has become. We are talking lizard-skin-dry: skin was peeling and texture was showing through makeup. Thankfully I did not experience any irritation or other side-effects aside from dryness, but still figured that it would be best for me to discontinue the use and switch back to my old favourite Avocado eye cream.


I think Kiehl's did a fantastic job formulating their Powerful-Strength Line-Reducing Concentrate; it feels amazing on the skin and you can notice visible results practically after one-two weeks of using it. Naturally, the longer it is in your daily skincare product rotation, the better your skin will become. I think that it is a great product for those of you who are 30+ and are on a hunt for effective and potent Vitamin C products, those that will not burn your skin off or cover it in blackheads or pustule (fancy word for a blemish). If we are in the same age pool though and you are in your 20s, I would save a lovely product like this for later and let your skin naturally sort out collagen production, while you can maintain a healthy look of the skin by using good old AHAs and BHAs to control texture and further balance your transepidermal hydration levels by working with good moisturizers and linoleic/oleic acid rich oils that also have a ton of antioxidants to further protect your skin. And don't forget about SPF of course.

As for the Powerful-Strength Line-Reducing Eye-Brightening Concentrate; well, it was not really my cup of tea so to speak (although I did have incredibly high hopes for it after using the brand's other eye cream for years now) but it doesn't mean you guys would have the same experience. Skincare is very personal and one size certainly doesn't fit all; so I would suggest going to Kiehl's and asking for a sample of this eye cream, so to see how your skin would react to it. Chances are that if your under eye is pretty good and not dry at all, it might work brilliantly for you. At this point I wonder if I will ever switch from Creamy Eye Treatment With Avocado to anything else - so definitely come back to this site or my Instagram for more product updates in the future.

PR samples; this review is not sponsored, full disclaimer here.

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