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Skin science article

Paula's Choice BHA 9 Treatment Versus Isntree Chestnut BHA 2% Clear Liquid

Paula's Choice BHA 9 Treatment Versus Isntree Chestnut BHA 2% Clear Liquid This acne treatment is formulated around Salicylic Acid to clear breakouts and refine the look of pores. This pore-care exfoliator is formulated around Salicylic Acid to refine the look

Paula's Choice BHA 9 Treatment Versus Isntree Chestnut BHA 2% Clear Liquid

This acne treatment is formulated around Salicylic Acid to clear breakouts and refine the look of pores.

This pore-care exfoliator is formulated around Salicylic Acid to refine the look of pores and clear breakouts.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Propylene Glycol

PEG-75 Stearate

PEG-8

Water

Salicylic Acid

Glycerin

Avena Sativa Kernel Extract

Butylene Glycol

Boerhavia Diffusa Root Extract

Sea Whip Extract

Arginine

Polysorbate 20

Disodium EDTA

Propylene Glycol, PEG-75 Stearate, PEG-8, Water, Salicylic Acid, Glycerin, Avena Sativa Kernel Extract, Butylene Glycol, Boerhavia Diffusa Root Extract, Sea Whip Extract, Arginine, Polysorbate 20, Disodium EDTA

Propanediol

1,2-Hexanediol

Castanea Crenata Shell Extract

Sodium Hydroxide

Biosaccharide Gum-1

Ethylhexylglycerin

Xanthan Gum

Hydroxyethylcellulose

Citric Acid

Dipotassium Glycyrrhizate

Hyaluronic Acid

Hydrolyzed Hyaluronic Acid

Sodium Citrate

Sodium Hyaluronate

Salix Alba Bark Extract

Allantoin

Water, Butylene Glycol, Propanediol, 1,2-Hexanediol, Salicylic Acid, Castanea Crenata Shell Extract, Sodium Hydroxide, Glycerin, Biosaccharide Gum-1, Ethylhexylglycerin, Xanthan Gum, Hydroxyethylcellulose, Disodium EDTA, Citric Acid, Dipotassium Glycyrrhizate, Hyaluronic Acid, Hydrolyzed Hyaluronic Acid, Sodium Citrate, Sodium Hyaluronate, Salix Alba Bark Extract, Allantoin

Reviews

Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.

Disodium 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%.

Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.

Topically, glycerin does several things at once:

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Salicylic 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.

Water. 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!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

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Formula cabinet

Ingredients & structured notes

Ingredient index

Paula's Choice Calm Redness Relief Repairing SerumIngredients explained

  1. 01Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product.
  2. 02It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water.
  3. 03Expand to read more
  4. 04Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying.
  5. 05One more thing: the water used in cosmetics is purified and deionized (it means that almost all of the mineral ions inside it is removed). Like this, the products can stay more stable over time.
  6. 06A natural moisturizer that’s also in our skin
  7. 07A super common, safe, effective and cheap molecule used for more than 50 years
  8. 08Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
  9. 09Effective from as low as 3% with even more benefits for dry skin at higher concentrations up to 20-40%
  10. 10High-glycerin moisturizers are awesome for treating severely dry skin
  11. 11It’s naturally in our skin and behaves there like a sponge
  12. 12It can bind up to 1000 times its own weight in water
  13. 13It is a big molecule from repeated subunits (polymer) so different molecular weight versions exist (unfortunately there is no way to determine MW from INCI list only)
  14. 14High-molecular-weight-HA (>500 kDa) is an excellent surface hydrator, skin protectant and can act as an osmotic pump helping water-soluble actives to penetrate deeper into the skin
  15. 15Low-molecular-weight-HA (< 500 kDa) can hydrate the skin somewhat deeper though it is still a big molecule and works mainly in the epidermis (outer layer of the skin)
  16. 16Low-molecular-weight-HA might also help the skin to repair itself by increasing its self-defense (~ 200kDa used in the study)
  17. 17Ultra-low-molecular-weight-HA (<50kDa) is a controversial ingredient and might work as a pro-inflammatory signal molecule
  18. 18Beta-Glucan is a nice big molecule composed of many smaller sugar molecules (called polysaccharide). It’s in the cell walls of yeast, some mushrooms, seaweeds, and cereals.
  19. 19It’s a real goodie no matter if you eat it or put it on your face. Eating it is anti-diabetic, anti-cancer, and even lowers blood cholesterol.
  20. 20Putting it on your face also does a bunch of good things: it‘s shown to have intensive skin repairing & wound healing properties, it’s a mild antioxidant, a great skin soother, and moisturizer, and it even shows promising anti-aging benefits.
Source · incidecoder.com
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Product index

Related product references

Product

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Source: incidecoder.comView reference →
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Comparison edit

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