Skin science article
PURITO AHA BHA Refreshing Solution Versus Paula's Choice Skin Perfecting 6% Mandelic Acid + 2% Lactic Acid Liquid Exfoliant
PURITO AHA BHA Refreshing Solution Versus Paula's Choice Skin Perfecting 6% Mandelic Acid + 2% Lactic Acid Liquid Exfoliant This smoothing exfoliator is formulated around Glycolic Acid and Salicylic Acid to refine skin texture and clear breakouts. This smoothi
PURITO AHA BHA Refreshing Solution Versus Paula's Choice Skin Perfecting 6% Mandelic Acid + 2% Lactic Acid Liquid Exfoliant
This smoothing exfoliator is formulated around Glycolic Acid and Salicylic Acid to refine skin texture and clear breakouts.
This smoothing exfoliator is formulated around Mandelic Acid and Lactic Acid to refine skin texture and brighten dull-looking skin.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Salix Alba Bark Water
Butylene Glycol
Dipropylene Glycol
Glycolic Acid 7%
Tromethamine
Water
Salicylic Acid 2%
1,2-Hexanediol
Sodium Citrate
Arginine
Caprylyl Glycol
Citric Acid 0.28%
Hydroxyacetophenone
Pentylene Glycol
Allantoin
Dipotassium Glycyrrhizate
Disodium EDTA
Salix Alba Bark Water, Butylene Glycol, Dipropylene Glycol, Glycolic Acid 7%, Tromethamine, Water, Salicylic Acid 2%, 1,2-Hexanediol, Sodium Citrate, Arginine, Caprylyl Glycol, Citric Acid 0.28%, Hydroxyacetophenone, Pentylene Glycol, Allantoin, Dipotassium Glycyrrhizate, Disodium EDTA
2,3-Butanediol
Mandelic Acid
Lactic Acid
Sodium Hydroxide
Myrica Cerifera Fruit Extract
Akebia Quinata Stem Extract
Prunus Lannesiana Flower Extract
Lactobacillus Ferment Lysate
Saccharomyces Lysate
Achillea Millefolium Extract
Saccharide Isomerate
Sodium Phytate
Xanthan Gum
Citric Acid
Sodium Benzoate
Water, 2,3-Butanediol, Mandelic Acid, Lactic Acid, Sodium Hydroxide, Myrica Cerifera Fruit Extract, Akebia Quinata Stem Extract, Prunus Lannesiana Flower Extract, Lactobacillus Ferment Lysate, Saccharomyces Lysate, Achillea Millefolium Extract, Saccharide Isomerate, Arginine, Hydroxyacetophenone, Butylene Glycol, Sodium Phytate, Pentylene Glycol, Xanthan Gum, Citric Acid, Sodium Citrate, 1,2-Hexanediol, Caprylyl Glycol, Sodium Benzoate
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Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.
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 preservatives
Arginine is a semi-essential amino acid. This just means our bodies can product a bit on its own, but sometimes needs a little boost from food sources.
It is a part of your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.
Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.
A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.
Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.
One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.
Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.
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.
Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.
Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.
Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).
Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.
Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.
However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.
Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.
In skincare formulas, citric acid can:
While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.
Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.
Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.
However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.
Hydroxyacetophenone is a small phenolic molecule that earns its place in a formulas as an antioxidant and preservative booster.
As a phenol, it is able to neutralize free radicals to protect both the product and the skin from oxidative stress.
Though it can't kill microbes on its own, it works as a good supporting agent when combined with other preservatives like Phenoxyethanol or 1,2-Hexanediol.
This ingredient naturally occurs as piceol in Norwegian spruce needles (~0.4-1.1% dry weight and in cloudberries). Though the cosmetic-grade material is synthesized for purity and consistency.
You'll usually see it used at low levels and suppliers recommend up to 1% added to a water phase.
Safety testing was done at concentrations like 0.05% in SPF products and 0.5% in a Human Repeated Insult Patch Test. The safety evidence is assuring; this ingredient is safe for cosmetics in current use and also holds safety status as a food flavoring as well.
An honest caveat: the "soothing" and "anti-inflammatory" claims come mostly from supplier marketing rather than published clinical trials. The Cosmetic Ingredient Review's own literature search found no useful efficacy studies on this ingredient.
So the antioxidant and preservative-boosting roles are the well supported ones while the calming benefit is plausible but thinly evidenced.
Overall, this is a well-tolerated, low-irritation multitasker that quietly helps a formula stay fresh and stable.
Pentylene Glycol (1,2-pentanediol) is a multitasking little diol with three main roles in a formula:
Research on alkanediols (the family pentylene glycol belongs to) show they work by disrupting microbial cell membranes. This disruption helps the primary preservative system in a product work more effectively at lower doses.
On the safety side, the Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe as used in current cosmetic practices + concentrations.
Typical use levels in a formula run about 1-5%.
Sodium Citrate is the sodium salts of citric acid. In skincare, it is used to alter pH levels and acts as a preservative.
Its main functions are to maintain the pH of a product and neutralize metal ions.
The acidity of our skin is maintained by our glands and skin biome; normal pH level of skin is slightly acidic (~4.75-5.5).
Being slightly acidic allows our skin to create an "acid mantle". This acid mantle is a thin barrier that protects our skin from bacteria and contaminants.
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!