Cosrx BHA Blackhead Power Liquid has been a huge part of my routine since mid November of 2017. Since I am very acne-prone I use it daily, and sometimes twice daily. I had a period of time in January 2018 where my acne was flaring up and I couldn't seem to get it under control so I switched to using The Ordinary Salicylic Acid 2% Solution and Oxy Deep Pore Medicated Acne Pads with 2% salicylic acid. Things got worse: my acne persisted and my skin became even more irritated. I switched back to Cosrx BHA Blackhead Power Liquid and my skin gradually began to recover from irritation. However, I am not saying that it was the two salicylic acid containing products that caused the acne or the irritation.

I have been making all kinds of skincare mistakes despite supposedly knowing better. I ended up somewhat over-exfoliated recently due to a combination of things, as well as finding out the hard way that one of my trigger ingredients is lanolin. Long story short: Eucerin Aquaphor causes my skin to break out in painful little pustules that aren't fixed by applying acne solutions. It took me a while to realize that my acids were only worsening the problem by weakening the already irritated skin barrier that I would then apply more Aquaphor to fix. Once I ditched the Aquaphor the pustules healed and I was no longer stuck in the cycle of trying to treat a reaction as acne.

I have played around with The Ordinary Salicylic Acid 2% Solution and the Oxy Deep Pore Medicated Acne Pads since ditching Eucerin Aquaphor, and they have not caused anywhere near the level of irritation I previously experienced. However, I still don't like using them as much. Why? Well, the Oxy Pads are rough, stinky and very drying, and The Ordinary Salicylic Acid 2% Solution can be drying as well. These problems are not entirely the fault of the 2% salicylic acid that they contain. It's likely that my skin prefers Cosrx BHA Blackhead Power Liquid not because of the 4% betaine salicylate it contains, but because of the overall formulation. Let's look at the ingredients for all three products.

BHAs all day

Cosrx BHA Blackhead Power Liquid (list taken from Ulta): Salix Alba (Willow) Bark Water, Butylene Glycol, Betaine Salicylate, Niacinamide, 1,2-Hexanediol, Arginine, Panthenol, Sodium Hyaluronate, Xanthan Gum, Ethyl Hexanediol.

*sings* One of these things is not like the other..

The Ordinary Salicylic Acid 2% Solution (from their website): Aqua (Water), Hamamelis Virginiana Leaf Water, Cocamidopropyl Dimethylamine, Salicylic Acid, Dimethyl Isosorbide, Trisodium Ethylenediamine Disuccinate, Citric Acid, Polysorbate 20, Hydroxyethylcellulose, Ethoxydiglycol, Potassium Sorbate, Sodium Benzoate, 1,2-hexanediol, Caprylyl Glycol.

See? Look at how rough that pad is!

Oxy Deep Pore Medicated Acne Pads (transcribed from container): Salicylic Acid 2%, Non-Medicinal Ingredients: Fragrance, Isoceteth-20, PEG-8/SMDI Copolymer, Purified Water, SD Alcohol 40D, Triethanlomine, Trisodium EDTA.


Looking at all three lists of ingredients doesn't really clarify things. For one thing, I don't think the ingredients on the container of Oxy Pads is in order of most to least, rather it looks like alphabetical ordering. Why else would Fragrance be listed before Purified Water? Nonetheless, alcohol is apparent in the smell and feel of the liquid which is probably why these pads are very drying. I also really dislike the rough texture of the pad. It's very scratchy feeling ◉_◉

The difference between the ingredient lists for Cosrx BHA Blackhead Power Liquid and The Ordinary Salicylic Acid 2% Solution doesn't tell me much about why my skin prefers one over the other. To really find out, I will probably have to quit using the Cosrx for around 3 months and use The Ordinary instead. I'm not super keen to do that right at the moment since I like how the Blackhead Power Liquid feels under my other layers of skincare. Instead, we'll look at what are the differences between salicylic acid and betaine salicylate, and why they are used in concentrations of less than 2% and 4% respectively.

Let's begin with salicylic acid since it's what I am more familiar with; having used it on and off since I was eleven years old. Salicylic acid is a beta hydroxy acid, or BHA, originally derived from willow bark. Currently, it can be derived from a number of other sources including wintergreen, peanuts, licorice root, calendula (marigold), plantain, and wheat. The proper chemical name is 2-Hydroxybenzoic acid and Health Canada has it listed on its Cosmetic Ingredient Hotlist in the List of Ingredients that are Restricted for Use in Cosmetic Products. Surprisingly there isn't a tonne of other information to be found on Health Canada's site specifically pertaining to salicylic acid. All I've got is: "For topical use only. Permitted at concentrations equal to or less than 2%." Okie dokie then.

In Canada and the U.S. its concentration is capped at 2% for leave-on topical preparations (with the exception of certain foot condition treatments) but in Korea it is limited to 0.5%. At that low of a concentration it is unlikely to be effective for people suffering from severe acne. I believe this is why Cosrx has chosen to use betaine salicylate since the maximum allowable concentration is much higher. I have yet to find what the official maximum allowable concentration is, but I have not seen any product using higher than 4% betaine salicylate. One source states that 4% betaine salicylate acts the same as 2% salicylic acid, but I haven't seen any hard data to support that statement. Betaine salicylate has virtually no information listed about it on Health Canada. It is not mentioned whatsoever in Canada's Cosmetic Ingredient Hotlist. Nor, is it listed in the Cosmetics Ingredient Review, the Cosmetics Info, the Cosmetics and Toiletries, nor the Prospector databases. To me this indicates that either it is sufficiently uncommon and therefore merits no mention, OR it is completely safe with no side effects at all. My guess is the former.

Well that didn't clarify much. Image source 1 and source 2

Betaine salicylate is an ester of salicylic acid, meaning that a salicylic acid molecule has undergone a process called esterification in order to attach a betaine molecule. I last took chemistry in high school so I honestly can't completely understand the process. What I've read is essentially that the salicylic acid is placed in a waterless alcoholic solution and has a betaine molecule attached to it. Chemistry is magic, guys.

So what about the the betaine part of betaine salicylate? What is it and why is it there? Betaine is an amino acid derivative originally discovered in sugar beets. There are many types of betaine, but in skincare the type you find is actually trimethylglycine or TMG. You probably have seen it in many of your own skincare products because it acts as a skin conditioner and moisturizer, and is generally considered as a soothing superstar. If you check the ingredients in your hair care products you'll almost definitely find betaine because of the characteristic silky feeling that it imparts. This article from 2010 quickly summarizes some of the studies about betaine's safety, uses, and benefits. Most notable in my opinion is that "betaine has a good anti-inflammatory action on superficial inflammatory lesions". Less red and swollen acne spots gets a win in my book!

Alright, so they put the salicylic acid and betaine together to form betaine salicylate. Now what? From Patent US3002886A: "Betaine salicylate is slightly soluble in water (0.74 gram percent at 25 C.), and the pH of the saturated aqueous solution is pH 2.7. The compound is soluble in methanol, ethanol and isopropanol and insoluble in anhydrous ether and petroleum benzine. Betaine salicylate is not hygroscopic and is stable to heat and light."

When I first read that I had trouble understanding what 0.74 gram percent actually meant in practical terms. Particularly since 'gram percent' is non-standard notation these days. After some reading and using this great guide, I determined that the author means w/w% which is definitely something I have seen on my products without ever knowing what it meant. In fact, if you scroll up to the image of the container of Oxy pads and look closely at the right-most image you will see it too! Right there, on the line for medicinal ingredients it says "Salicylic Acid 2.0% w/w". Huh, why did I always ignore the w/w? Welp, the more you know I guess.

Okay, but if you can only dissolve 0.74g of betaine salicylate into 100g of water (or mL since they are equivalent for pure water in standard atmospheric condition) to reach a saturated solution, how can my skincare product have a 4% (ie. 4g betaine salicylate to 100g water) concentration? I am going to skip answering that question because I can't do it without going even further off-topic. Let's just say it has to do with the other solvents like butylene glycol, dimethyl isosorbide, and alcohol present in the formulations of the products we're talking about. I can't go down every rabbit hole, despite my natural inclination to so I'm noping right out of this one.

I pretty much only use these guys now since the OXY pads are ouch!

In conclusion, I don't think I answered my questions at all. I feel like I know less now that I did when I first began. There are so many factors in the formulation of a skincare product, and even more when that skincare product contains active ingredients. I hope that you learned something from reading this overly long post and if I have made mistakes, pleasepleaseplease correct me by commenting below!

To learn more about the power of acids in skincare, please check out Lab Muffin and her fantastic guides. There are lots and lots of blog posts about beta hydroxy acids and more over at Point of Interest, Vanity Rex, Graceful Face, Simple Skincare Science, The Wanderlust Project, Beauty Brains, Elizabeth Renee, and Escaping Mars.

Further Reading (but if you don't want to, that's okay)

Skincare Guide to Beta Hydroxy Acids

International Journal of Cosmetic Sciences

Comparison study of glycolic acid versus salicylic acid for sun damage

Salicylic acid as a skin whitening ingredient

Salicylic acid in wash-off products

Plant based sources of salicylic acid and other acne treatments

Delivery methods for salicylic acid in skincare

Sodium salicylate for anti-aging


Sources relating to the creation and purchase of betaine salicylate and salicylic acid

Patent for creating tablets of betaine salicylate

Cosmetics and Toiletries profile of salicylic acid

Prospector profile of salicylic acid

Prospector data relating to purchase of salicylic acid

Prospector data relating to purchase of betaine salicylate

in-cosmetics Korea data relating to purchase of betaine salicylate

I have been using Illi Total Aging Care Cleansing Oil since January 1st 2018, and these are my thoughts about this product. Spoiler Alert: it's not my favourite.. but it could be yours!

I bought it from a seller on eBay back in early October but due to shipping delays I did not receive it until the middle of December. By that time I had already begun using Banila Co. Clean It Zero and so I wasn't ready to add the Illi to my routine just then. I am doing my best to test products in a fair manner by using them for a long enough period of time to get a real feel for how they work for me. This review is based on having used 3/4 of the bottle of Illi, approximately 100mL of Banila Co Clean it Zero, 75mL of Heimish All Clean Balm, and a sampling of others. During this period I have used a lot of different leave-on skincare products, but I kept my second cleanser constant. You can see a lot more about my products and routine by checking out my spreadsheet.

Cleansing with oil has been a big part of my routine right from the start. I have very acne prone skin despite being in my thirties because it's pretty much always been this way. I have been trying to work with the skin I was born with ever since I began getting acne at the tender age of eleven. You can learn more about my history here. 

I never wore much makeup because my ideal was to have perfect skin that didn't need any cover. Haha, joke's on me. I had cystic acne all throughout my teenage years and up to my mid-20s. Even now in my early thirties I still have a fair bit of acne but thankfully no cysts. What kick-started my journey in to AB was the reality of aging with its fine lines, wrinkles, and sun damage.

Avoiding further damage means wearing a daily sunscreen in the proper quantity of 2mg/cm^2, or about 1/2 teaspoon for face and neck. I plan to review a bunch of sunscreens later because I am in the process of trying about 6 different ones in order to find my ideal daily driver. For now though, the focus of this post is on how to get that sunscreen OFF.

The signature move - sourced from giphy

Others have written extensively on the virtues of double cleansing, arguably the signature move and most important step in a Asian Beauty routine. Double cleansing also happens to be my favourite part of the whole routine. I typically zen out for 20+ minutes massaging the oil into my face. I am perhaps unusual in this preference because it seems that many AB lovers quickly cruise through the double cleanse in order to get to the 'meat' of the routine; that being all of the amazing toners, skins, essences, serums, lotions, emulsions, masks, creams, packs, and more available to those of us willing to look beyond the aisles of our local drugstores.

I get that, I do. BUT some of my best results to date have been specifically due to prolonged oil massage plus the use of lactic acid, and later tretinoin. The acid clears the surface layers of dead skin and the long massage makes the closed comedones nearly jump from my pores. My skin has become dramatically smoother and more acne-free because I spend the time nearly every night to let the oil permeate deep into my pores. Funnily enough, I'm not sure it really matters what oil you use. As long as the oil you choose has enough time to mix with the natural oils of your face, I'm quite confident it will remove the debris of the day.

This review is supposed to be about the Illi Total Aging Care Cleansing Oil, but to be honest it's not the one for me. I really wanted to get my hanbang on and Fiddy from Fifty Shades of Snail declared this cleansing oil as her HG back in 2015. The Beauty Witches loved it too, so what is my problem?? I figured I could skip the search and just fall in love, but alas no. Still, I really do like it just not enough to repurchase it. The scent and texture were originally part of the appeal of the Illi Cleansing Oil but in the end I want a thicker, less scented oil.

The make a fetching pair, do they not?

It begins as a thin-textured oil which spreads quickly and smoothly across my skin. In order to get enough for my face and neck I use 3 full pumps and I smooth on each individual pump before drawing more. I lightly rub the cleansing oil around so that I can be sure I've covered everything and sometimes I let it sit undisturbed for a few minutes to really settle in. Most of the time I just jump right into the massage. I find that the Illi takes longer to break up my sunscreen than both plain olive oil and Banila Co. Clean It Zero. It also begins to thicken and sort of gum up as I get into the 10 minute mark of my massage. The Illi cleansing oil loses a lot of its slip and generally feels unpleasant to use after fifteen minutes. This is partly the fault of certain sunscreens because it does not gum up equally for all products.

The smell changes too. It starts out lovely with scents of honey and flowers, and then quickly moves into a more gentle floral and herbal tone. Then the oil takes on a vegetal scent which is pleasant at first but seems to get kind of gross and cloying about the same time the oil changes in texture.

In contrast with Banila Co. Clean It Zero, the Illi just can't keep up. Banila Co. Clean It Zero spreads easily just like the Illi does but it actually stays smooth and slippy no matter how long I decide to massage my face. Likewise, the scent starts out soft and pleasantly fruity and then stays that way. It does fade with time, but I vastly prefer that to being assaulted with the smell of strange vegetable matter. If you search 'Illi Total Aging Care Cleansing Oil' on r/AsianBeauty you will find tonnes of glowing reviews. People are saying that this oil smells amazing, washes away cleanly, and doesn't strip skin of all its natural goodness so it leaves your face soft and happy. They are all completely accurate too.

If I was the kind of person who moved efficiently through the double cleanse I would probably love this oil. The bottle is cute, the initial smell is great, it emulsifies and washes away swiftly, and you get to move on with the rest of your routine in no time. I would definitely recommend this to people just getting used to the idea of using an oil cleanser because the pump format makes it much more space efficient and easy to use versus the tub and spatula of Clean It Zero. For myself however, I will not be repurchasing. It is on the pricier side too at about 25CAD for 200mL of oil so I have steered budget-minded friends away from it.

My rating therefore is three out of five:

To see how I rate products click here.

I have already purchased DHC Deep Cleansing Oil, however I have decided not to open it until I have used the last drops left in the bottle of Illi Total Aging Care Cleansing Oil. DHC was recommended to me over and over again by various AB-minded folks so I took the plunge. It costs even more, at 35CAD per 200mL, so this had better be good  ಠ_ಠ

I am not affiliated in any way with any brands and these products were purchased by me with my own money. I am reviewing them because I feel strongly that more reviews of more products leads to better information for everyone.