The INKEY List Lactic Acid Serum Versus Drunk Elephant Protini Powerpeptide Resurfacing Serum

The INKEY List Lactic Acid Serum Versus Drunk Elephant Protini Powerpeptide Resurfacing Serum

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

This smoothing serum is formulated around Lactic Acid and Sh-Oligopeptide-1 to refine skin texture and soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Lactic Acid

Propanediol

Glycerin

Sodium Hydroxide

PPG-26-Buteth-26

Sodium Hyaluronate

Phenoxyethanol

PEG-40 Hydrogenated Castor Oil

Ethylhexylglycerin

Trisodium Ethylenediamine Disuccinate

Agastache Mexicana Flower/Leaf/Stem Extract

Water, Lactic Acid, Propanediol, Glycerin, Sodium Hydroxide, PPG-26-Buteth-26, Sodium Hyaluronate, Phenoxyethanol, PEG-40 Hydrogenated Castor Oil, Ethylhexylglycerin, Trisodium Ethylenediamine Disuccinate, Agastache Mexicana Flower/Leaf/Stem Extract

Dicaprylyl Carbonate

Squalane

Glycine Max Seed Extract

Sclerocarya Birrea Seed Oil

Camellia Sinensis Seed Oil

Sodium PCA

Caprylic/Capric Triglyceride

Borago Officinalis Seed Oil

Tremella Fuciformis Polysaccharide

Tocotrienols

Sh-Oligopeptide-1

Sh-Oligopeptide-2

Sh-Polypeptide-1

Sh-Polypeptide-9

Sh-Polypeptide-11

Copper Palmitoyl Heptapeptide-14

Heptapeptide-15 Palmitate

Palmitoyl Tetrapeptide-7

Palmitoyl Tripeptide-1

Palmitoyl Tripeptide-38

Palmitoyl Hexapeptide-12

Tripeptide-1

Pyrus Malus Fruit Extract

Panthenol

Sodium Hyaluronate Crosspolymer

Sodium Lactate

PCA

Alanine

Arginine

Glycine

Histidine

Isoleucine

Phenylalanine

Proline

Serine

Threonine

Valine

Adenosine

Nymphaea Alba Root Extract

Bacillus/Folic Acid Ferment Filtrate Extract

Symphytum Officinale Callus Culture Extract

Dextran

Oryza Sativa Bran Oil

Linoleic Acid

Linolenic Acid

Butylene Glycol

Acetyl Glutamine

Coconut Alkanes

Coco-Caprylate/Caprate

Pentylene Glycol

Isomalt

Lecithin

Xanthan Gum

Aspartic Acid

Phytosphingosine

Phospholipids

Glycine Soja Sterols

Tocopherol

Citric Acid

Lactic Acid/Glycolic Acid Copolymer

Polyvinyl Alcohol

Sodium Benzoate

Hydroxypropyl Cyclodextrin

Polysorbate 20

Caprylyl Glycol

Phenylpropanol

Chlorphenesin

Carbomer

Glyceryl Caprylate

Water, Glycerin, Lactic Acid, Dicaprylyl Carbonate, Squalane, Sodium Hydroxide, Glycine Max Seed Extract, Sclerocarya Birrea Seed Oil, Camellia Sinensis Seed Oil, Sodium PCA, Caprylic/Capric Triglyceride, Borago Officinalis Seed Oil, Tremella Fuciformis Polysaccharide, Tocotrienols, Sh-Oligopeptide-1, Sh-Oligopeptide-2, Sh-Polypeptide-1, Sh-Polypeptide-9, Sh-Polypeptide-11, Copper Palmitoyl Heptapeptide-14, Heptapeptide-15 Palmitate, Palmitoyl Tetrapeptide-7, Palmitoyl Tripeptide-1, Palmitoyl Tripeptide-38, Palmitoyl Hexapeptide-12, Tripeptide-1, Pyrus Malus Fruit Extract, Propanediol, Sodium Hyaluronate, Panthenol, Sodium Hyaluronate Crosspolymer, Sodium Lactate, PCA, Alanine, Arginine, Glycine, Histidine, Isoleucine, Phenylalanine, Proline, Serine, Threonine, Valine, Adenosine, Nymphaea Alba Root Extract, Bacillus/Folic Acid Ferment Filtrate Extract, Symphytum Officinale Callus Culture Extract, Dextran, Oryza Sativa Bran Oil, Linoleic Acid, Linolenic Acid, Butylene Glycol, Acetyl Glutamine, Coconut Alkanes, Coco-Caprylate/Caprate, Pentylene Glycol, Isomalt, Lecithin, Xanthan Gum, Aspartic Acid, Phytosphingosine, Phospholipids, Glycine Soja Sterols, Tocopherol, Citric Acid, Lactic Acid/Glycolic Acid Copolymer, Polyvinyl Alcohol, Phenoxyethanol, Sodium Benzoate, Hydroxypropyl Cyclodextrin, Polysorbate 20, Caprylyl Glycol, Phenylpropanol, Chlorphenesin, Carbomer, Glyceryl Caprylate, Ethylhexylglycerin

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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.

Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:

The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

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:

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.

It’s often used to:

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

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.

Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.

In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

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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