Review: Naruko Dermalane Intensive Brightening Renewal Treatment 20% Mandelic Acid AHA

I have a complicated relationship with AHAs. They’re some of the most proven actives around for my skin concerns (brightening and anti-aging), but over the past year, I’ve looked for ways to pull back on them rather than go harder. Thanks to prescription tretinoin, I generally seek out products to strengthen my barrier rather than further thin it out. But AHAs have clear benefits (and I was bored of weak acids), so when Naruko’s US office sent me their Dermalane Intensive Brightening Renewal Treatment 20% mandelic acid serum a couple of months ago, I whipped out my pH strips and whispered to myself, “Let’s do this.”

The product reviewed in this post was provided by a Fifty Shades of Snail sponsor. Affiliate links are marked with an asterisk(*).

Naruko Dermalane Intensive Brightening Renewal Treatment review
DermaLane is Naruko’s more cosmeceutical-style skincare line, using well researched actives to target specific skin issues.

Purpose: Naruko DermaLane Intensive Brightening Renewal Treatment is a 20% mandelic acid AHA serum that claims to brighten skin tone and fade dark spots. As an AHA, it may also smooth skin texture and address some acne concerns.

Best suited for: All skin types except for very sensitive skin.

Do not use if: Your skin is currently overexfoliated or experiencing dryness, peeling, or irritation from retinoids or other actives; you are currently using another AHA exfoliant; you are allergic or sensitive to anything in the ingredients list; and/or you are unable or unwilling to use daily sunscreen.

When and how to use: Use 1-3 times a week after cleansing but before any hydrating toner, essence, serum, or cream steps in your skincare routine. Spread a thin layer of product over bare skin. Let dry for at least 10 minutes before following with any other skincare products. Use sunscreen daily when using this product and for at least 7 days after discontinuing use, as AHAs are photosensitizing.

Naruko DermaLane Intensive Brightening Renewal Treatment ingredients:  Purified water, butylene glycol, mandelic acid (20%), hyaluronic acid, arginine, propanediol, sodium lactate, niacinamide, gluconolactone, tranexamic acid, panthenol, lactic acid, sclerotium gum, glycyrrhiza glabra (licorice) root extract, essential oils of lavender (lavandula angustifolia), eucalpytus (eucalyptus globulus), marjoram (origanum marjorana), thyme (thymus vulgaris), clary sage (salvia sclarea), rosemary (rosmarinus officinalis), ho wood (cinnamonum camphora), phenoxyethanol, iodopropynyl butylcarbamate

Naruko DermaLane Intensive Brightening Renewal Treatment English ingredients

CosDNA analysis

Notable ingredients: The key ingredient in the Intensive Brightening Renewal Treatment is mandelic acid, an alpha hydroxy acid that seems to be gentler and more moisturizing, as well as more suitable for darker skin types, than more common AHAs like glycolic and lactic acid. The Intensive Brightening Renewal Treatment ups its brightening potential by including niacinamide, tranexamic acid, and licorice root extract in the formulation.

Down at the bottom of the list, things get a little less positive. Naruko uses several fragrant essential oils in this product, including lavender and eucalyptus, which may be irritating and offer minimal to no skin benefit. I’m guessing their function in the Intensive Brightening Renewal Treatment is to help cover up the smell of the AHAs, which can get a little stinky when unfragranced. Personally, I don’t have an issue with a few fractions of a drop of fragrant oils, but if you do, you may want to avoid this one or at least patch test extensively before going full-face with the product.

pH and free acid content: If you’re used to products like COSRX’s, Papa Recipe’s, or Paula’s Choice’s daily use AHAs, which use the acids in concentrations of 7-8% or so, then the Intensive Brightening Renewal Treatment’s 20% mandelic acid may sound scarily intense. But wait! It’s not that simple.

As with cleansers, pH matters with chemical exfoliants. For sciency reasons that Lab Muffin explains more clearly than I could, the lower the pH of the AHA or BHA product, the more the acid can actually absorb into skin and produce an exfoliating effect. I used my nice four-color pH testing strips* to check the pH of the Intensive Brightening Renewal Treatment. I also tested the pH of the product several times over the last two months to make sure it was stable, since some products’ pH may fluctuate. This product’s pH held steady at about a 4.

pH test of Naruko DermaLane Intensive Brightening Renewal Treatment 20% mandelic acid

Lab Muffin also has a handy free acid calculator, which I used to calculate the approximate percentage of free acids in the product and compare it to other AHAs I have on hand. Naruko’s product clocks in at about 4.09% free acid. This makes it stronger than COSRX’s AHA 7 Whitehead Power Liquid, which comes out to about 2.82%, and Papa Recipe’s White Flower Clear Up 8% AHA Gel, which I calculated at about 3.23%.

While the Intensive Brightening Renewal Treatment is clearly stronger than those common daily use AHAs, it’s nowhere near peel strength despite the high concentration of mandelic acid. I have a Make Up Artist’s Choice 25% mandelic acid peel that my friend and other self Chel decanted for me to try. That product has a pH between 1.5 and 2, according to my test strips. Its free acid percentage is about 24.06-24.7% depending on whether I put 1.5 or 2 into the pH value field of Lab Muffin’s calculator! That’s a lot of acid!!!!!

So why did Naruko choose to use such a high concentration of mandelic acid, but at a pH that would significantly weaken its effect? I don’t know. It’s possible that the brand wanted to make an AHA notably stronger than most 5-10% AHAs on the market, but found that boosting effectiveness while staying in that concentration range would require a pH low enough to greatly increase the chances of irritation. A high concentration to enable higher free acid content even at a more gentle pH level might be the compromise. But that’s just me writing beauty brand fanfiction really.

Anyway, knowing the free acid content of the product helps me know how to fit it into my routine. These days, I’d be comfortable using the COSRX or Papa Recipe AHA almost every day and the MUAC peel pretty much never (unlike Lord Fiddy, who last night put it on his entire face including eyelids). I settled on the higher end of Naruko’s recommended usage rate. I use it every other night.

Naruko DermaLane Intensive Brightening Renewal Treatment English instructions
I really appreciate the brand’s warning to use SPF during the day when using this product.


After my experiences with the odors of both COSRX’s and Papa Recipe’s AHAs (and the somewhat milder but still unpleasant scent of Paula’s Choice’s 8% AHA gel), my biggest worry with the DermaLane mandelic serum was how it would smell. Would it stink like a burning chemical tire fire (COSRX)? Would its scent be vaguely reminiscent of unwashed undergarments (Papa Recipe)? Would it have the sharp tang of overly fermented vinegar (Paula’s Choice)? And if it smelled like any of those products, would I be able to go nose-blind to it as I did to the COSRX?

There was one night when I thought things might be bad. I put the Intensive Brightening Renewal Treatment on my face and became convinced that my entire face smelled like fish. I remember a lot of panicky all-caps ranting in the Snailcast group chat about it.

Thankfully, I think I was just hallucinating the smell that night. For one thing, it wasn’t the first time I’d used the product. It had been active in my beauty stash for a couple of weeks at that point. And I never smelled that fishy funk again. Maybe I’d been visited by the ghost of some fish I once consumed at a sushi bar, I dunno. Point is, no, for me the DermaLane Intensive Brightening Renewal Treatment does not stink after all. For the most part, it just has a faint sourness to it. I can live with that, and happily.

Naruko DermaLane Intensive Brightening Renewal Treatment is a moderately thick, champagne-colored liquid in a simple dropper bottle.

Naruko Intensive Brightening Renewal Treatment review
That’s what champagne color looks like, right?

I dislike dropper bottles, since they expose the product to light and air each time you dispense it, increasing the chances of both contamination and premature breakdown of any light-sensitive components. I’d prefer a serious product like this one to be packaged in at least a pump bottle but ideally an airless pump.

With that being said, at least the bottle is opaque, and since I don’t use it every day and it is adequately preserved as far as I can tell, neither the contamination or oxidation issues should be serious ones.

Naruko 20% mandelic AHA English label

The serum spreads smoothly over my skin but doesn’t sink in or dry down immediately. Even at a very thin layer, it settles instead into a slightly oily-feeling film that turns tacky over the next few minutes. Since I use this product so early in my routine, I’d prefer it to have a more watery and quick-absorbing (or at least quick-disappearing) consistency. To be fair, though, I pile on plenty of other products afterwards and haven’t experienced problems with any of them absorbing more slowly than usual. The film this product creates is therefore really more of an aesthetic and tactile gripe for me than it is a functional one.

And in my experience, the effects of the Intensive Brightening Renewal Treatment more than make up for any of my minor gripes about it.

Within the first three weeks of use, the Intensive Brightening Renewal Treatment had purged several very, very, very deeply embedded clogs (we’re talking years-old clogs here) right out of my skin. These are clogs that no other AHA I’ve used has been able to touch. Clogs that had formed bumps I’d long ago learned to consider just a fact of my life. One clog that had been around for so long that I was starting to think I might need to get it checked out. And now they’re gone. Some surfaced as small, rapidly healed whiteheads (a classic purge). Others just fell out of my face in a glorious shower of grits.

A little bit after the one-month mark, I also began noticing other unmistakable improvements to my skin. Sunspots looked lighter, their edges fading away; my skin texture became smoother overall and much softer to the touch. I’m about two and a half months in with every-other-day use of the Intensive Brightening Renewal Treatment, continuing to see steady progress, and have no plans to change my AHA regimen anytime soon.

Fifty shades of snail skincare routine
It’ll stay in my evening routine for many months to come.

As far as overexfoliation goes, I’ve found that the higher strength of the Intensive Brightening Renewal Treatment does make finding the balance between maximum results and minimum sensitization trickier than it would be with a more conventional daily strength AHA product. I’ve bumped my frequency up a little, using it two nights in a row before taking a night off, and found that my skin will start to feel thin very quickly. It also starts to feel thin if I use any but my gentlest physical exfoliants. No more sugar scrubs for me–when I feel the need to do some manual exfoliation, I stick to my Goodal bubble pack or a nice mild gommage peel.

I also find that I need an extra night off of the product after doing my shitty home dermaplaning routine. (That involves wetting my face, putting on cleanser, then very lightly going over my skin with a fresh Venus razor, in case you’re interested. Best way I’ve found to keep my mustache in check while creating a great surface for makeup.)

While I don’t get any kind of tingle or burning sensation when I use this, the way I did with the MUAC 25% mandelic peel, the Intensive Brightening Renewal Treatment is stronger stuff than the acids I’m used to. Every other night works best for me. You may find yourself able to use it more or less frequently than I do, but no matter how tough you think your skin is, go slowly and carefully as you adjust your AHA routine.

naruko founder Niuer
Niuer would want you to be careful.

Conclusion: You guys should see the grits that pop out of my face since I started using this product. In the past 2+ months, the Naruko DermaLane Intensive Brightening Renewal Treatment has cleared out clogs I’ve been living with for months or years. It’s softened and faded plenty of my sunspots (both new and old) as well, and it makes my skin feel like the silkiest of silk–as long as I don’t get overexcited and use it more frequently than I should.

I’m not a fan of the dropper bottle or the slightly oily feel of the product, and some of you won’t be fans of the fragrant essential oils in it, but overall, this is an exceptional Asian exfoliant. (God knows there are few enough of those!) And since it’s a bit too strong for everyday use for me, the bottle should last me nearly half a year. I’m not even halfway through with it! I can’t wait to see how much more it improves my skin by the time I finish it.

Rating: 4.2/5

Rating scale:

1 – This should be taken off the market, or this failed at its one primary job.

2 – Caused me some problems or doesn’t work very well; would not buy again.

3 – Meh. Neither great nor bad.

4 – Pretty good. Worth rebuying.

5 – I’ll never be in the market for a replacement unless this one is discontinued.

Disclaimer: Reviews on this blog are descriptive, not prescriptive. Individual experiences with products may differ. As always, patch test, know your sensitivities, and remember, YMMV!

Where can I buy Naruko DermaLane Intensive Brightening Renewal Treatment 20% Mandelic Acid?

I received my bottle of Naruko DermaLane Intensive Brightening Renewal Treatment from Naruko Boutique USA*, where a 30ml bottle is currently $34.99*, qualifies for free shipping, and comes with a free hand and foot mask as a gift with purchase. The Naruko US site is also currently running a bunch of special mask promotions* for the holidays.

What’s the strongest exfoliant you’ve used? How did it go for you?


29 thoughts on “Review: Naruko Dermalane Intensive Brightening Renewal Treatment 20% Mandelic Acid AHA

  1. Another question about using this product. You suggested using this before the toner, but if I wipe a cotton pad of toner all over my face, won’t it remove this product if I put it on before the toner?


  2. Oh this sounds delicious. I’m really liking the Paula’ Choice Skin Perfecting 8% AHA gel (their 10% AHA Weekly Resurfacing Treatment is like Wildfire on my face). But I’ve been wanting to try a good mandelic acid that doesn’t sound like it’lol melt my face off my skull a la Raiders of the Lost Ark, sooo… Looks like I’m going to be sacrificing my wallet on the Naruko pyre, is what I’m saying.


  3. i usually wash my face, use the mizon aha/bha toner, and then the cosrx bha blackhead power liquid, and then the papa recipe 8% aha toner. if I swap my papa recipe out for this, do you think i will be overexfoliating?


  4. You mentioned the MUAC mandelic acid but have you tried it? Wondering how it compares to the Naruko one.
    Is Lord Fiddy OK? Does he still have a face?
    I use Alpha Hydrox 10% glycolic lotion about 5 nights out of the week. Occasional I’ll go for a 14% Alpha Hydrox swipe pad and I always regret it because it leaves me flaky the next day.

    Liked by 1 person

  5. Honestly, the MUAC 25% Mandelic scared me too at first, but the results totally won me over (whispers I’ve actually moved on to the 40% a few months back). Since it’s a chemical peel meant to be left on the skin for a few minutes then neutralised and washed off, as opposed to being left on all day/night, I can understand why it’s so strong. But yeah it’s definitely not recommended if you’re using Tret or any other strong stuff like prescription BP.


  6. I bought this product immediately after reading this review because my biggest skin issue right now is inflamed clogs/cysts that like to hang out forever. I’ve been using it every other day since it arrived, so three times now, and I noticed an immediate difference even after the first use. My general redness is reduced and my acne spots are calmer, less inflamed. After the third use my skin is noticeably smoother. I have a similar skin type (and age) to Fiddy, and my skin is easily irritated. However, I’m not using tret. I haven’t noticed any negative effects from this product so far. I’m thrilled with it and it’s my new favorite Naruko product.


  7. Great review! I’m actually in search of a new AHA treatment because I find Cosrx’s AHA 7 Whitehead Power Liquid a bit too aggressive for me (usage: twice I week). Do you think it’s worth trying Naruko in my case? Heaven knows I’d love to get rid of that clog between my eyebrows!


    1. If you find the Cosrx too aggressive, I’d say this one is likely to be as well since it has a higher percentage of free acids. I’m about to try a Swanicoco PHA exfoliant that I direct will


  8. Opps realised that I missed out that you mentioned that you only used it at night. Just bought the product after reading your review. Saw good results only after using the first night. Thank you for the detailed review!


  9. Do you still use cosrx blackhead liquid with this? Pondering whether I use the blackhead liquid with dermalane acid.


    1. You can, though personally I would suggest alternating nights at first. I haven’t used my BHA in a long time, since my tret seems to be keeping pores under control!


  10. Hi I have been lurking on your website. Thank you for your insights on these products. I wanted to ask if you still use OST C20 or C21.5 with any of these regimens. And if not why? Also I can’t seem to find this product on the Naruko website. Have they discontinued it?

    Thank you!


    1. I think they repackaged it into a different product line (AM/PM); I mentioned it to another commenter, that I’ll be checking with Naruko to see if that is the case!


    2. Hi! I use Timeless C+E+Ferulic Acid vitamin C serum now instead of C20 or C21.5, as I find the Timeless has an objectively better formulation (the C+E+ferulic combo is generally considered the most stable and effective) and it doesn’t oxidize as fast. I’ll be reviewing the Timeless this week actually!


  11. Every tried Garden of Wisdom’s Mandelic Acids? I know its not AB, but they seem to be a lot more reasonable in price.


  12. Hi Fiddy,
    Do you think it would reduce the effects of this acid to wipe off the reside after say, 30 minutes?


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