Cos De BAHA AC Azelaic Acid Hinokitiol Clear Skin
A highly rated serum with 12 ingredients, including BHA, retinoid, and niacinamide.
Overview
What it is
Serum with 12 ingredients that contains azelaic acid, BHA, hyaluronic acid, niacinamide and retinoid
Cool Features
It is cruelty-free and reef safe
Suited For
It has ingredients that are good for fighting acne, anti aging, dry skin, brightening skin, sensitive skin, oily skin, reducing pores, scar healing, dark spots and better texture
Free From
It doesn't contain any harsh alcohols, common allergens, parabens, silicones or sulfates
Fun facts
Cos De BAHA is from South Korea. This product is used in 31 routines created by our community.
We independently verify ingredients and our claims are backed by peer-reviewed research. Does this product need an update? Let us know.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Explained
Propylene Glycol is a synthetic, colorless, odorless liquid that has been a staple in cosmetics for decades. It is a skin conditioning agent, humectant, and solvent.
As a humectant, it draw water to the skin to reduce flaking and restore suppleness. It's also a solvent that helps dissolve other actives and keeps formulas stable across temperature changes.
The CIR Expert Panel has confirmed this ingredient to be nontoxic and clinical studies show no sensitization at cosmetic use concentrations.
True allergic reactions are quite rare: a 15-year retrospective study of 6,751 patients found only 0.31% had a positive reaction (and less than half were considered clinically relevant).
It seemed that when sensitization does occur, it's most commonly linked to topical medication (like corticosteroids) and not cosmetics. Allergic contact dermatitis also appears largely limited to individuals with underlying skin conditions.
Overall, propylene glycol is a well-studied ingredient that most people can tolerate without issue.
Learn more about Propylene GlycolWater. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!
Learn more about WaterNiacinamide is a multitasking form of vitamin B3 that strengthens the skin barrier, reduces pores and dark spots, regulates oil, and improves signs of aging.
And the best part? It's gentle and well-tolerated by most skin types, including sensitive and reactive skin.
You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.
In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.
If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.
When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.
When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.
In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).
Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.
Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.
The type of niacinamide used in skincare is synthetically created.
Learn more about NiacinamideAzelaic acid is a multitasker ingredient that helps treat acne, pigmentation, and irritation. It is a great option for sensitive skin.
What makes it special?
OTC Azelaic acid is usually available in concentrations from 10-15% and anything over requires a prescription.
Here's what each tier does best:
Unlike other acids, azelaic acid will not make your skin more photosensitive/sun sensitive.
Though this ingredient is naturally occurring in grains like wheat, rye, and barley, it is usually synthetically created for cosmetics to ensure stability and effectiveness.
Learn more about Azelaic AcidPolysorbate 20 is a gentle, water-soluble emulsifier and mild surfactant. It stops oil and water from separating to keep your formulas blended and stable.
It also acts as a mild penetration enhancer by helping active ingredients absorb slightly better.
The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.
Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).
True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.
Because it is derived from lauric acid, it may not be fungal acne safe.
Learn more about Polysorbate 201,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.Â
It is a:
- Humectant, drawing moisture into the skin
- Emollient, helping to soften skin
- Solvent, dispersing and stabilizing formulas
- Preservative booster, enhancing the antimicrobial activity of other preservativesÂ
Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
Interestingly, the size of the molecule affects its behavior:
Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.
Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.
You'll typically see concentrations between 0.1-2% for this ingredient.
Learn more about Sodium HyaluronateSalicylic Acid (also known as beta hydroxy acid or BHA) is a well-known ingredient for treating skin that struggles with acne and clogged pores. It exfoliates both the skin's surface and deep within the pores to help clear out buildup, control oil, and reduce inflammation.
Unlike AHAs (alpha hydroxy acids), salicylic acid is oil-soluble. This allows it to penetrate into pores which makes it especially effective for treating blackheads and preventing future breakouts.
Salicylic acid is also known for its soothing properties. It has a similar structure to aspirin and can calm inflamed or irritated skin, making it a good option for acne-prone skin that is also sensitive.
Concentrations of 0.5-2% are recognized by the U.S. FDA as an over-the-counter topical acne product.
It can cause irritation and/or dryness if one's skin already has a compromised moisture barrier, so it's best to focus on repairing that before introducing this ingredient into your routine.
While salicylic acid does not increase sun sensitivity, it’s still important to wear sunscreen daily to protect your skin.
If you are looking for the ingredient called BHA or Butylated Hydroxyanisole, click here.
Learn more about Salicylic AcidHinokitiol is a naturally occurring compound in the wood of trees like the hinoki cypress or western red cedar. It mostly has antistatic and hair conditioning functions.
Lab studies have shown it has broad-spectrum antibacterial activity, antifungal properties, anti-inflammatory effects, and antioxidant activity.
This ingredient is also known as tea tree oil. It has antioxidant, anti-inflammatory, and antimicrobial properties.
Tea tree oil is a complex lipophilic (fat-loving) oil that contains around 100 compounds with terpinen-4-ol being the most abundant (~40%).
Terpinen-4-ol is responsible for tea tree oil's broad-spectrum antimicrobial activity and makes it a well-researched option for acne.
Clinical studies support 5% tea tree oil as an effective topical treatment for mild to moderate acne. A study with 124 patients compared 5% tea tree oil gel to 5% benzoyl peroxide and both reduced acne (though tea tree oil worked more slowly).
Besides acne, it is also seen in anti-dandruff shampoos and scalp treatments for it's antimicrobial and anti-seborrheic properties.
Safety-wise, the allergic potential of low concentrations on healthy skin is considered low. However, oxidized (old or improperly stored) tea tree oil is a stronger sensitizer.
Irritation can also occur if using the undiluted oil on skin; it's best to use this ingredient as part of a carefully crafted cosmetic formula. This is because regulations require tea tree oil in cosmetics to be stabilized to prevent degradation.
This ingredient has been deemed safe up to 2% in shampoo, 1% in cleansers, and 0.1% in face cream by the EU's Scientific Committee on Consumer Safety (SCCS).
There is some lab evidence that tea tree oil is antifungal against Malassezia, but it is a supportive option at best and not a replacement for proven antifungal treatments.
Learn more about Melaleuca Alternifolia Leaf OilRetinol is a gold-standard ingredient for anti-aging. It is a form of Vitamin A and belongs to the class of retinoids that also includes tretinoin.
Why is retinol famous?
It has the most scientific studies backing up its skin benefits out of all the non-prescription ingredients.
Retinol is proven to:
This is why retinol is effective at removing wrinkles, fading dark spots, treating acne, and reducing the appearance of pores.
Studies show retinol is less effective when exposed to UV. Be sure to look for appropriate packaging to keep your retinol potent (similar to Vitamin C).
Using retinol or any retinoids will increase sun-sensitivity in the first few months. Though studies show retinoids increase your skin's natural SPF with continuous use, it is best to always wear sunscreen and sun-protection.
We recommend speaking with a medical professional about using this ingredient during pregnancy.
Retinol may cause irritation in some people, so be sure to patch test. Experts recommend 'ramping up' retinol use: start using this ingredient once a week and work up to using it daily.
Read about Tretinoin
Learn more about RetinolDisodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.
This ingredient mainly works behind the scenes and helps with:
On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.
One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).
Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.
You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.
Learn more about Disodium EDTAReviews
Average rating of all formulations of this product: 5.00
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Where it's from
Cos De BAHA is a Korean brand
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The data we've presented on this page has been verified by a member of the SkinSort Team.
Read more about us· Updated October 22, 2025 • Added by Frans