Dr. Dennis Gross Skincare C+ Collagen Brighten & Firm Vitamin C Serum Versus Dr. Dennis Gross Skincare Vitamin C Lactic 15% Firm & Bright Serum

Dr. Dennis Gross Skincare C+ Collagen Brighten & Firm Vitamin C Serum Versus Dr. Dennis Gross Skincare Vitamin C Lactic 15% Firm & Bright Serum

This brightening serum is formulated around 3-O-Ethyl Ascorbic Acid and Niacinamide to brighten dull-looking skin and soften the look of wrinkles.

This anti-aging serum is formulated around Ascorbic Acid and Lactic Acid to soften the look of wrinkles and brighten dull-looking skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

3-O-Ethyl Ascorbic Acid

Niacinamide

Glycereth-7 Triacetate

Lactic Acid

Sd Alcohol 40-B

Hydroxyethylcellulose

Dimethyl Isosorbide

Ascorbic Acid

Collagen Amino Acids

Superoxide Dismutase

Glycine

Carnitine Hcl

Ubiquinone

Hexylresorcinol

Emblica Officinalis Fruit Extract

Hydrolyzed Soy Protein

Tetrahexyldecyl Ascorbate

Isoquercetin

Mandelic Acid

Pueraria Lobata Root Extract

Curcuma Longa Root Extract

Phytic Acid

Citric Acid

Tetrasodium EDTA

Sodium Citrate

Butylene Glycol

Xanthan Gum

Polysorbate 20

T-Butyl Alcohol

Sodium Hydroxide

Polysorbate 80

Denatonium Benzoate

Benzyl Alcohol

Phenoxyethanol

Sodium Benzoate

Potassium Sorbate

Water, Glycerin, 3-O-Ethyl Ascorbic Acid, Niacinamide, Glycereth-7 Triacetate, Lactic Acid, Sd Alcohol 40-B, Hydroxyethylcellulose, Dimethyl Isosorbide, Ascorbic Acid, Collagen Amino Acids, Superoxide Dismutase, Glycine, Carnitine Hcl, Ubiquinone, Hexylresorcinol, Emblica Officinalis Fruit Extract, Hydrolyzed Soy Protein, Tetrahexyldecyl Ascorbate, Isoquercetin, Mandelic Acid, Pueraria Lobata Root Extract, Curcuma Longa Root Extract, Phytic Acid, Citric Acid, Tetrasodium EDTA, Sodium Citrate, Butylene Glycol, Xanthan Gum, Polysorbate 20, T-Butyl Alcohol, Sodium Hydroxide, Polysorbate 80, Denatonium Benzoate, Benzyl Alcohol, Phenoxyethanol, Sodium Benzoate, Potassium Sorbate

Dipropylene Glycol

Ricinoleth-40

Aminomethyl Propanol

Tocopherol

Glycyrrhiza Glabra Root Extract

Ferulic Acid

Morus Alba Fruit Extract

Sodium Hyaluronate

Glycolic Acid

Adenosine

Water, Dipropylene Glycol, Ascorbic Acid, Dimethyl Isosorbide, Ricinoleth-40, Aminomethyl Propanol, Lactic Acid, Tocopherol, Glycyrrhiza Glabra Root Extract, Ferulic Acid, Morus Alba Fruit Extract, Sodium Hyaluronate, Glycolic Acid, Adenosine, Glycerin, Phenoxyethanol

Reviews

Be the first to review

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Ascorbic Acid is is pure Vitamin C and is the biologically active form used directly by skin.

Not only is vitamin C great for your overall health and immune system, but it also has plenty of benefits for your skin. It is best supported by academic literature for:

Topical vitamin C has been shown to help neutralize oxidative stress from UV and pollution, helping to improve photoaging and hyperpigmentation when used consistently.

One clinical study found that using 5% topical vitamin C for six months improved signs of photodamaged skin, both on the surface and in the deeper structural layers of the skin.

While vitamin C doesn’t replace sunscreen, studies show it can boost photoprotection when combined with Vitamin E and ferulic acid. These two ingredients help improve stability and protective effects.

The big downside of this ingredient is formulation difficulty. Vitamin C is prone to oxidation and doesn't penetrate the skin unless formulated correctly. Research found that vitamin C absorbs into the skin best at a low pH (< 3.5) with about 20% being the upper limit for effective absorption.

Skin levels can saturate after repeated application; this means your skin won’t keep absorbing more once it’s full of vitamin C. This is why more isn’t always better with vitamin C and why very high concentrations don’t necessarily give extra benefits.

Ascorbic acid generally works well with many skincare ingredients but can be irritating when combined with other active ingredients. Strong oxidizing acne treatments like benzoyl peroxide can reduce the effectiveness of vitamin C if they are used at the same time; they are often recommended for use at different times of day.

Read more about other types of Vitamin C:

Foods rich with vitamin C include oranges, strawberries, broccoli, bell peppers, and more. When consuming Vitamin C, your skin receives a portion of the nutrients.

Dimethyl Isosorbide (often shortened to DMI) is a sugar-derived solvent made from sorbitol. It's used to dissolve tricky ingredients and help them mix smoothly into a formula.

Many actives sit as gritty crystals when undissolved, so DMI swoops in to full dissolve them. This helps improve texture, stability, and how evenly an active is distributed.

It does have a penetration-enhancing reputation that is a bit more nuanced than marketing suggests; a cell study on human skin found that 10% DMI didn't significantly boost the permeation of Hydroquinone, Salicylic Acid, or Octadecenedioic Acid compared to controls (though it did improve their solubility in the formula itself).

Typical usage concentrations usually range from 1-10% depending on the formula's needs; this ingredient is also well tolerated at these levels.

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.

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