Biologique Recherche Lotion P50 1970 Versus PCA Skin Smoothing Toner

Biologique Recherche Lotion P50 1970 Versus PCA Skin Smoothing Toner

This smoothing toner is formulated around Niacinamide and Lactic Acid to refine skin texture and clear breakouts.

This smoothing toner is formulated around Lactic Acid and Citric Acid to refine skin texture and brighten dull-looking skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

Phenol

Niacinamide

Vinegar

Ethoxydiglycol

Magnesium Chloride

Lactic Acid

Arctium Lappa Root Extract

Salicylic Acid

Sodium Benzoate

Sulfur

Water, Glycerin, Phenol, Niacinamide, Vinegar, Ethoxydiglycol, Magnesium Chloride, Lactic Acid, Arctium Lappa Root Extract, Salicylic Acid, Sodium Benzoate, Sulfur

Citric Acid

Aloe Barbadensis Leaf Juice

Hydrastis Canadensis Extract

Cucumis Sativus Fruit Extract

Salvia Officinalis Leaf Extract

Calendula Officinalis Flower Extract

Paullinia Cupana Seed Extract

Hedera Helix Leaf/Stem Extract

Tetrasodium EDTA

Water, Lactic Acid, Citric Acid, Glycerin, Aloe Barbadensis Leaf Juice, Hydrastis Canadensis Extract, Cucumis Sativus Fruit Extract, Salvia Officinalis Leaf Extract, Calendula Officinalis Flower Extract, Arctium Lappa Root Extract, Paullinia Cupana Seed Extract, Hedera Helix Leaf/Stem Extract, Tetrasodium EDTA

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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.

Arctium Lappa Root Extract is from the burdock plant. It is a botanical extract with skin conditioning and soothing properties.

Burdock root contains polyphenols that have anti-inflammatory and antioxidant activity. This can help explain why it's used to calm irritated or red skin.

Evidence in humans is limited to the non-root parts of this plant; topical arctium fruit extract showed improvements in dermal extracellular matrix metabolism and visible wrinkles.

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.

Lactic Acid is another well-loved alpha hydroxy acid (AHA). It is gentler than glycolic acid but still highly effective.

Its main role is to exfoliate the surface of the skin by loosening the “glue” that holds dead skin cells together. Shedding those old cells leads to smoother, softer, and more even-toned skin.

Because lactic acid molecules are larger than glycolic acid, they don’t penetrate as deeply. This means they’re less likely to sting or irritate, making it a great choice for beginners or those with sensitive skin.

Like glycolic acid, it can:

Lactic acid also acts as a humectant (like hyaluronic acid). It can draw water into the skin to improve hydration and also plays a role in the skin's natural moisturizing factor (NMF) in the form of sodium lactate.

Studies show it can boost ceramide production to strengthen the skin barrier and even help balance the skin’s microbiome.

To get results, choose products with a pH between 3-4.

Lower strengths (5-12%) focus on surface exfoliation; higher strengths (12% and up) can reach deeper in the dermis (deeper, supportive layer) to improve skin texture and firmness over time.

Though it was originally derived from milk, most modern lactic acid used in skincare is vegan. It is made through non-dairy fermentation to create a bio-identical and stable form suitable for all formulations.

When lactic acid shows up near the end of an ingredient list, it usually means the brand added just a tiny amount to adjust the product’s pH.

Legend has it that Cleopatra used to bathe in sour milk to help reduce wrinkles.

Lactic acid is truly a gentle multitasker: it exfoliates, hydrates, strengthens, and brightens. It's a great ingredient for giving your skin a smooth, glowing, and healthy look without the harshness of stronger acids.

Read more about some other popular AHA's 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!

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