Cosmedix Serum 24 Rapid Renewal Complex Versus PCA Skin Total Strength Serum

Cosmedix Serum 24 Rapid Renewal Complex Versus PCA Skin Total Strength Serum

This anti-aging serum is formulated around Retinol and Retinal to soften the look of wrinkles and refine skin texture.

This anti-aging serum is formulated around Gluconolactone and Sh-Oligopeptide-1 to soften the look of wrinkles and refine skin texture.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Hamamelis Virginiana Water

Carthamus Tinctorius Oleosomes

Phospholipids

Glycerin

Sodium Acrylates Copolymer

Hydrogenated Polyisobutene

Sodium Lactate

Glycosaminoglycans

Polysorbate 20

Cetyl Alcohol

Retinol

Retinal

Proline

Sodium Hyaluronate

Helianthus Annuus Seed Oil

Tapioca Starch

Leuconostoc/Radish Root Ferment Filtrate

Lonicera Caprifolium Flower Extract

Lonicera Japonica Flower Extract

Santalum Austrocaledonicum Wood Oil

Lavandula Hybrida Oil

Galactoarabinan

Sodium Polygamma-Glutamate

Tocopherol

Squalane

Hydroxypropyl Starch Phosphate

Dimethicone

Polyglyceryl-10 Stearate

Gluconic Acid

Xanthan Gum

Tetrasodium EDTA

Citric Acid

Alcohol

Potassium Sorbate

Sodium Glycolate

Sodium Hydroxide

Trisodium EDTA

Benzoic Acid

Sodium Benzoate

Linalool

Limonene

Water, Hamamelis Virginiana Water, Carthamus Tinctorius Oleosomes, Phospholipids, Glycerin, Sodium Acrylates Copolymer, Hydrogenated Polyisobutene, Sodium Lactate, Glycosaminoglycans, Polysorbate 20, Cetyl Alcohol, Retinol, Retinal, Proline, Sodium Hyaluronate, Helianthus Annuus Seed Oil, Tapioca Starch, Leuconostoc/Radish Root Ferment Filtrate, Lonicera Caprifolium Flower Extract, Lonicera Japonica Flower Extract, Santalum Austrocaledonicum Wood Oil, Lavandula Hybrida Oil, Galactoarabinan, Sodium Polygamma-Glutamate, Tocopherol, Squalane, Hydroxypropyl Starch Phosphate, Dimethicone, Polyglyceryl-10 Stearate, Gluconic Acid, Xanthan Gum, Tetrasodium EDTA, Citric Acid, Alcohol, Potassium Sorbate, Sodium Glycolate, Sodium Hydroxide, Trisodium EDTA, Benzoic Acid, Sodium Benzoate, Linalool, Limonene

Alcohol Denat.

Gluconolactone

Hydroxypropyl Cyclodextrin

Ammonium Acryloyldimethyltaurate/Vp Copolymer

Cocos Nucifera Fruit Juice

Adenosine

Aesculus Hippocastanum Seed Extract

Melaleuca Alternifolia Leaf Oil

Menthyl Lactate

Silybum Marianum Extract

Totarol

Tocotrienols

Elaeis Guineensis Oil

Sh-Oligopeptide-1

Palmitoyl Tripeptide-38

Water, Hamamelis Virginiana Water, Glycerin, Glycosaminoglycans, Alcohol, Alcohol Denat., Gluconolactone, Hydroxypropyl Cyclodextrin, Ammonium Acryloyldimethyltaurate/Vp Copolymer, Sodium Benzoate, Xanthan Gum, Lonicera Caprifolium Flower Extract, Cocos Nucifera Fruit Juice, Adenosine, Aesculus Hippocastanum Seed Extract, Lavandula Hybrida Oil, Lonicera Japonica Flower Extract, Melaleuca Alternifolia Leaf Oil, Menthyl Lactate, Santalum Austrocaledonicum Wood Oil, Silybum Marianum Extract, Sodium Hyaluronate, Totarol, Tocotrienols, Elaeis Guineensis Oil, Citric Acid, Phospholipids, Potassium Sorbate, Tocopherol, Sh-Oligopeptide-1, Palmitoyl Tripeptide-38

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

This ingredient is also called ethanol or ethyl alcohol. It is denatured, meaning made undrinkable for cosmetic use.

In formulas, it:

Is it bad for your skin?

The answer comes down to concentration. Patch and wash studies have found highly concentrated alcohol-based hand rubs (60-100%) cause less barrier disruption than washing with a basic detergent like SLS. The only measurable effect in these studies was a temporary dip in skin hydration.

Concentrations below 12-15% in leave-on cosmetics is generally well-tolerated. Concentrations above start to see increased transepidermal water loss (TEWL) and reduced hydration.

In concentrations about 58%, it creates temporary channels in your skin's lipid layers to become more permeable and allow other ingredients to slip through easily.

This ingredient can be up to 80% of the formula in alcohol-based perfumes.

Overall, this ingredient is probably harmless if found lower down an ingredients list but worth side-eyeing if it's high up (especially if your barrier is already struggling).

Alcohol can worsen dry skin, eczema, and oily skin, especially at higher concentrations. This is because it can increase transepidermal water loss and decrease hydration to disrupt the skin barrier.

According to the National Rosacea Society based in the US, you should be mindful of products with these alcohols in the top half of ingredients.

True allergic contact dermatitis to ethanol is uncommon, but be sure to patch test if you have dry or sensitive skin.

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.

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.

We don't have a description for Glycosaminoglycans yet.

Hamamelis Virginiana Water is made by distilling parts of the witch hazel plant. You can also call this ingredient "witch hazel water".

The name 'Hamamelis Virginiana Water' refers to the distillation product used in cosmetics. On the other hand, 'Witch Hazel' refers to the active drug ingredient.

Unless it is specified to be non-alcohol, many types of witch hazel ingredients are distilled in denatured alcohol.

Witch Hazel water is an astringent, anti-inflammatory antioxidant, and antibacterial ingredient.

It contains tannins. Tannins have a drying effect when used on skin by constricting proteins. The constriction also minimizes the appearance of pores.

Both the tannins and fragrance found in witch hazel may be skin-sensitizing.

Witch hazel water gets anti-inflammatory and antibacterial properties from its catechin and gallic acid content.

Indigenous groups have used witch hazel to help treat inflammation in North America for centuries.

Lavandula Hybrida Oil is an oil.

This Honeysuckle flower extract comes from the Italian honeysuckle. It is an antioxidant, antimicrobial, and fragrance.

Both this and the Japanese Honeysuckle are rich in a natural paraben that give it antimicrobial property. They are effective in inhibiting bacteria, yeast, and mold.

Honeysuckle contains flavonoids and saponins. Both of these components are natural antioxidants that can help soothe the skin.

As most flowers do, honeysuckle has a natural fragrance.

Lonicera Japonica Flower Extract comes from the honeysuckle flower.

Honeysuckles have skin protecting, anti-viral, and anti-inflammatory properties. It contains many antioxidants, such as luteolin, caffeic acid, loniflavone, and chlorogenic acids.

This honeysuckle is native to East Asia and used in traditional Chinese medicine to treat fever and inflammation.

Phospholipids are a family of skin-identical lipids that makeup the structural backbone of every cell membrane in your body.

In cosmetics, they function as skin conditioning agents with emulsifier and surfactant properties. They're typically sourced from soybean or sunflower lecithin (or sometimes egg yolk or marine sources).

Because they mirror the lipids naturally found in the deeper layers of your skin, topical phospholipids help reinforce the lipid matrix, reduce transepidermal water loss, and leave skin feeling conditioned.

They're also used to form liposomes, or tiny self-assembling vesible used to stabilize actives like vitamin c or retinol. This helps these ingredients integrate into the upper layers of skin more easily.

Phospholipids are compatible with everything and the CIR Expert Panel has concluded them to be safe at current use levels.

Some types of phospholipids include:

Potassium Sorbate is a preservative used to prevent yeast and mold in products. It is commonly found in both cosmetic and food products.

This ingredient comes from potassium salt derived from sorbic acid. Sorbic acid is a natural antibiotic and effective against fungus.

Both potassium sorbate and sorbic acid can be found in baked goods, cheeses, dried meats, dried fruit, ice cream, pickles, wine, yogurt, and more.

You'll often find this ingredient used with other preservatives.

Santalum Austrocaledonicum Wood Oil is a fragrance and is an oil.

Sodium Benzoate is a preservative. It's used in both cosmetic and food products to inhibit the growth of mold and bacteria. It is typically produced synthetically.

Both the US FDA and EU Health Committee have approved the use of sodium benzoate. In the US, levels of 0.1% (of the total product) are allowed.

Sodium benzoate works as a preservative by inhibiting the growth of bacteria inside of cells. It prevents the cell from fermenting a type of sugar using an enzyme called phosphofructokinase.

It is the salt of benzoic acid. Foods containing sodium benzoate include soda, salad dressings, condiments, fruit juices, wines, and snack foods.

Studies for using ascorbic acid and sodium benzoate in cosmetics are lacking, especially in skincare routines with multiple steps.

We always recommend speaking with a professional, such as a dermatologist, if you have any concerns.

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.

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

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!

Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.

On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.

Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.

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