A FULL REVIEW OF THE RX COSRX DERM SERUMS

A FULL REVIEW OF THE RX COSRX DERM SERUMS

COSRX is a well known Korean skincare brand whose philosophy is very simple- simple ingredients that result in great formulas. One of their most popular products is the COSRX Advanced Snail Mucin Essence which is still an internet sensation, for good reason. You can read a full review of the product here.

COSRX launched the RX derm serums on the 30th of May, 00:00 PST which featured three different highly concentrated serums, all of which were reportedly sold out  on COSRX official website within 24 hours of its release. These highly concentrated serums are based on research with the optimal combination of active ingredients for your skin concerns.

I was kindly gifted these products by StyleKorean and COSRX in exchange for my honest review. The RX COSRX Derm Serums consist of three serums: the Vitamin C 23 Serum, the Niacinamide 15 Serum and the Hyaluronic Acid 3 Serum. 

After using these serums for a couple of weeks, here are my thoughts.

Are these serums worth the buy?

COSRX VITAMIN C 23 SERUM

This serum is formulated with 23% pure Vitamin C that is intended to fade acne scars, brighten and restore uneven skin tone. It is formulated to maximize effectiveness of the product while minimizing irritation. 

The Cosrx RX Vitamin C 23 Serum

The Cosrx RX Vitamin C 23 Serum

Highly concentrated vitamin C serums are known to be highly susceptible to oxidation and are prone to exploding due to internal gas generation. To combat this, COSRX developed a packaging that allows the container to expel gas while preventing the inflow of oxygen which can in turn cause oxidation. The product has a two (2) months PAO (Period After Opening); after which, the product can lose some or most of its efficacy.

Description

This product comes in a dark reagent-like 20mL bottle with a screw cap. It also came with a dropper in its packaging. The dropper is black as opposed to white which tends to stain over time. Its content is pale yellow in colour. It has an oily feel but not slippery as you would expect for most Vitamin C serums. There is a slight but noticeable smell. Like most vitamin C serums, it has that signature hotdog water smell but it doesn’t linger after use. It is fragrance free and vegan-friendly.

The Cosrx RX Vitamin C 23 Texture

The Cosrx RX Vitamin C 23 Texture

How to Use

After cleansing, shake the bottle lightly from side to side and apply a few drops to dry skin. Use fingertips to gently massage and absorb the serum. Start from the inside of the face working towards the edges.

Ingredients

Water, Ascorbic Acid(23%), Propanediol, Dimethicone, Tromethamine, Panthenol, Ethyl Ascorbyl Ether, Squalane, Caffeine, Sodium Chloride, Sodium Hyaluronate, Sodium Sulfite, Disodium EDTA, Glutathione, Adenosine, Acetyl Glucosamine, Gardenia Florida Fruit Extract, Allantoin, Dextrin, Tocotrienols, Tocopherol, Elaeis Guineensis (Palm) Oil, Butylene Glycol, Arginine, Niacinamide, Pentylene Glycol, Alcohol Denat., Helianthus Annuus (Sunflower) Seed Oil, Glycyrrhiza Glabra (Licorice) Root Extract, Methyl Trimethicone, Carthamus Tinctorius (Safflower) Seed Oil, Camellia Japonica Seed Oil, Daucus Carota Sativa (Carrot) Root Extract, Beta-Carotene

What the product claims to do

The COSRX Vitamin C 23 Serum claims to effectively prevent melanin synthesis, fade acne scars and hyperpigmentation. It also claims to help brighten skin’s complexion. It should help to fight off free radicals and protect against cellular damage, thus keeping the skin healthy. The concentration of Vitamin C in this product will help promote collagen synthesis to improve early signs of ageing, diminish fine lines and enhance elasticity.

It also contains tocotrienol- a super vitamin E which works synergistically with vitamin C to double up effectiveness. 

This formulation contains sodium hyaluronate which will keep the skin hydrated. It also contains niacinamide, a great antioxidant with skin healing properties. COSRX also formulated this product with allantoin which is meant to soothe and relieve irritation. This serum, although highly concentrated, has been formulated to be suitable for use, anytime during the day.

Lastly, COSRX claims that this serum has a double-layer structure with an oil layer on top to maintain freshness and delay oxidation of the product.

My Personal Experience– COSRX Vitamin C Serum Review

When I received the products in this collection, I was highly impressed by how much thought COSRX put into them- from the ingredients, texture and the elegantly detailed packaging. I noticed a soda pop like sound when I opened this product for the first time. COSRX had explained the cause of this sound meticulously. This is because the container needs to expel gas whilst blocking the inward flow of oxygen to safely house the highly concentrated pure vitamin C formula and subsequently preventing oxidation caused by external factors. 

COSRX Vitamin C serum has a slightly oily feel; not too thick, not too watery. It absorbs into my skin just as quickly as it is applied which is a huge bonus to me. I have previously used The Ordinary Ascorbic acid 8%+ Alpha Arbutin 2% which has a more oily texture and takes more time to absorb. A comparison is here if you’re curious. 

I noticed some tingling upon first application only. I have used this product every morning before my sunscreen since I have received it. Since then, I have noticed significant change in the overall brightness of my skin. I loved the product so much that I already repurchased it.

Where to Purchase

COSRX

StyleKorean

Yesstyle

RATING- 5.0/5.0

THE NIACINAMIDE 15 SERUM

Niacinamide is a multi-beneficial ingredient which can help with brightening uneven skin tone, reducing acne and post-acne scars, fading hyperpigmentation as well as improving skin texture. This 15% concentrated niacinamide serum was formulated based on COSRXs’ research that customers were more inclined to using niacinamide for its acne fighting and post-acne benefits as opposed to its other benefits. 

Cosrx RX Niacinamide 15 Serum

Cosrx RX Niacinamide 15 Serum

This serum contains N-acetylglucosamine, zinc PCA and allantoin which work together to combat acne at all stages, from cause to resolution, exfoliating, soothing and clearing post acne marks. 

Description

The product comes in a 20mL almost black coloured glass bottle with white sticker labelling. The bottle is very thick and well made. The dropper is shorter than most droppers you would find in a serum. This is because of the small nature of the bottle as well as the overall size of the product. The dropper is also black in colour, which I appreciate.

The product inside is a translucent silky texture. It feels smooth against the skin once applied, creating a thin layer of hydration.

The smell is nothing like other niacinamide serums I have used in the past. It had absolutely no scent or fragrance whatsoever. This is intriguing because most products with Zinc usually have a subtle iron-like smell. It is not sticky or tacky. It also layers well with other products in my routine.

How to Use

After cleansing, apply a few drops to the skin. Use fingertips to gently massage to absorb the serum into the skin.

Ingredients

Water, Pentylene Glycol, Niacinamide(15%), Butylene Glycol, Acetyl Glucosamine, 1,2-Hexanediol, Zinc PCA, Trehalose, Hydrolyzed Sclerotium Gum, Pullulan, Allantoin, Ethylhexylglycerin, Sodium Phytate, Tocopherol

What the product claims to do

It aims to provide total acne care by controlling sebum production, soothing acne inflammation and diminishing post acne scars. The 15% concentration of niacinamide should also help reduce the appearance of pores.

This product contains Zinc PCA which COSRX claims in this formulation to help reduce excess sebum and balance oily skin. It will also help inhibit inflammation and promote recovery of damaged skin.

My Personal Experience

I used this product every other day so as to ease it into my routine. Since I already us ae 10% niacinamide in my routine, my skin was used to a high percentage niacinamide. I did not find this product to be irritating in any way.

With consistent use, I noticed that this product helped with pore reduction- although very minimally. It also helped to control excessive sebum. However, I have not noticed any brightening using this product. I always focus on the antioxidant effects of niacinamide in my routine as opposed to its other benefits like brightening and acne care. This product at 15% gives a great antioxidant kick. 

Cosrx RX Niacinamide 15 Serum Texture

Cosrx RX Niacinamide 15 Serum Texture

I still don’t use it every day because I find that it may be too much for my skin. One thing I definitely appreciate is how it has helped tighten my pores and reduce excessive sebum production. I would thus recommend it to anyone who has oily skin or large pores.

I don’t have acne so I am unable to verify its efficacy as regards acne reduction and care. The texture of this product makes it so easy to apply. I appreciate the fact that it has no smell or added fragrance. It is such a great serum and definitely worth repurchasing in my opinion.

Where to Purchase

COSRX

StyleKorean

Yesstyle

RATING- 4.7/5- Worth Repurchasing

THE HYALURONIC ACID 3 SERUM

Hydration is very important in any routine and hyaluronic acid is well known for its ability to hold up to one thousand times its weight in water. This product can thus help to hold water in the skin and keep the skin hydrated for long periods of time. Most commercially distributed hyaluronic acid serums contain less than or 2% hyaluronic acid in them. In fact, some dermatologists have opined that 1- 2% is the optimal concentration of hyaluronic acid you should put in a solution to avoid any drying effects.

The Cosrx RX Hyaluronic Acid 3 Serum

The Cosrx RX Hyaluronic Acid 3 Serum

However, COSRX created this serum with 3% hyaluronic acid, combined with NMF and ceramide. The formulation is completely safe at this percentage and COSRX claims the product will provide a high level of hydration with their formulation. It should be great for all skin types and skin conditions.

Description

The packaging is similar to the Niacinamide 15 serum. It comes in a 20mL bottle and has a subtle- almost unnoticeable chemical like scent. I didn’t find it to be bothersome at all. 

Cosrx RX Hyaluronic Acid 3 Serum

Cosrx RX Hyaluronic Acid 3 Serum Texture

The serum itself has a nice silky texture which actually reminds me a lot of The Inkey List Polyglutamic Acid. It is a lighter consistency and creates a smooth finish after application. It does not contain any added fragrance.

How to Use

After cleansing, apply a few drops to damp skin. Use fingertips to gently massage and absorb the serum, starting from the inside of the face and working towards the edges.

Ingredients

Water, Butylene Glycol, Propanediol, Glycerin, Sodium Hyaluronate(3%), Pentylene Glycol, 1,2-Hexanediol, Diethoxyethyl Succinate, Sodium Polyacryloyldimethyl Taurate, Betaine, Xanthan Gum, Dimethicone, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Sodium PCA, Sodium Lactate, PCA, Glyceryl Acrylate/Acrylic Acid Copolymer, Hydrogenated Lecithin, Ethylhexylglycerin, Serine, Alanine, Glycine, Sodium Phytate, Sorbitan Isostearate, PVM/MA Copolymer, Glutamic Acid, Citric Acid, Lysine HCl, Threonine, Arginine, Sodium Methyl Stearoyl Taurate, Proline, Ceramide NP, Cholesterol, Caprylic/Capric Triglyceride, Phytosphingosine, Stearic Acid, Oleic Acid, Alcohol, Tocopherol, Lactic Acid, Caprylyl Glycol, Caprylhydroxamic Acid

What the product claims to do

COSRX claims that this product will recharge the skin with hydration while alleviating dryness and restoring the skin’s moisture balance. It claims to be more hydrating than most hyaluronic acid serums because of the 3% concentration of hyaluronic acid in this product. The Natural Moisturising Factors in this product should help improve skin barrier while protecting against dryness and dehydration. It is also fortified with Ceramides which should help protect the skin from external stressors and prevent the evaporation of hydration.

My Personal Experience

The feel of this product on the skin is absolutely phenomenal. The first thing I noticed about this product the moment I applied it was that the finish is silky. It creates a smooth layer of hydration on my skin. I would attribute this to the added ceramides in this product.

I love this product so much but I did not notice any extra significant hydration that I can’t find in any other hyaluronic acid serum. It however, does remind me a lot of The Inkey List Polyglutamic Acid in terms of feel and hydration. A full review of The Inkey List Polyglutamic Acid is here. I find myself gravitating to it everyday because of the way the texture feels on my skin.

Where to Purchase

COSRX

StyleKorean

Yesstyle

RATING- 5/5

ARE THESE SERUMS CONCENTRATIONS TOO HIGH?

A couple of people online have shared their concerns about the formulations being too high. However, COSRX has put a lot of thought into the formulation… such that even sensitive skin was put into mind when formulating.

Of course, you do not need these high levels of concentration to see results or have the perfect skincare routine. However, I would assume that people with resilient skin or seasoned skincare users, looking to incorporate something with a higher concentration without worrying about irritation will love these products.

COSRX seems to have made the formulations intentionally and safely for the skin. However, ensure you do a patch test before you fully commit to any product. My skin did not have any adverse reactions from these products at their concentrations.

CONCLUSION

COSRX did it again with these products. They are definitely worth the buy- each having their own perks and place in my skincare routine now. The formulations seem to be well thought through and they clearly live up to their claims.