Remedy For Daily Defense 15% Vitamin C Antioxidant Complex Brightening Serum Versus Remedy For Skin Elasticity Copper Peptide Complex Advanced Firming Serum

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.

Read more about some other popular AHA's here:

This ingredient contains a group of yellow pigments called curcuminoids (mostly curcumin) that give it genuine antioxidant and anti-inflammatory activity in skin.

Reviews of topical clinical studies have found turmeric/curcumin to be generally well-tolerated and useful across conditions like eczema and mild inflammation.

One thing working in its favor is that curcumin barely penetrates; in lab skin-permeation testing, the curcuminoids mostly stayed in the outermost layer of skin. This is a good thing because its soothing and antioxidant activity is a surface-level job anyway.

At this time, industry data shows there's no single "correct" cosmetic percentage. It's used across a wide range depending on the product and varies from tiny fractions of a percent up to a few percent.

Allergy-wise, curcumin is a documented (but uncommon) contact allergen. It can also cross react with related plants, so anyone with a turmeric/ginger/cinnamon allergy or reactive skin should patch test first.

When applied to the skin, ectoin helps bind water molecules to protect our skin. The water forms a sort of armor for the parts of our skin cells, enzymes, proteins, and more.

Besides this, ectoin has many uses in skincare:

A study from 2004 found ectoin to counteract the damage from UV-A exposure at different cell levels. It has also been shown to protect skin against both UV-A, UV-B rays, infrared light, and visible light.

Studies show ectoin to have dual-action pollution protection: first, it protects our skin from further pollution damage. Second, it helps repair damage from pollution.

In fact, ectoin has been shown to help with:

Fun fact: In the EU, ectoin is used in inhalation medication as an anti-pollution ingredient.

Ectoin is a highly stable ingredient. It has a wide pH range of 1-9. Light, oxygen, and temperature do not affect this ingredient.

The chemical name for this ingredient is Tetrahydromethylpyrimidine Carboxylic Acid.

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

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.

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.

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.

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.

Antioxidants help fight free-radical molecules that may damage your skin's DNA. This may help with the signs of aging. Due to its antioxidant property, it is used to help treat chronic inflammation.

In cosmetics, SOD is usually obtained from marine phytoplankton, bovine liver, horseradish, cantaloupe, and certain bacteria.

The three major families of SOD include: Copper/Zinc, Iron/Manganese, and Nickel.

When eating SOD-rich foods, our bodies break it down into amino acids before absorption. Foods that contain SOD include: melons, citrus, spinach, broccoli, kale, almonds, sunflower seeds, and blue-green algae.

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!