Skinerie Vitamin C And Ferulic Acid Illuminating Serum

Methylpropanediol is able to add a bit of moisture to the skin. It also helps other ingredients be better absorbed into the skin, such as salicylic acid.

In a formula, it does the 3 classic vitamin C jobs: it acts as an antioxidant, helps brighten skin tone by inhibiting tyrosinase, and supports collagen.

The evidence is reasonably solid for a cosmetic ingredient; Liao and colleagues (2018) showed it's significantly more stable than ascorbic acid while still being effective.

A 2021 study by Zerbinati and colleagues tested a serum with 30% 3-O-ethyl-l-ascorbic acid and 1% lactic acid significantly increased collagen production, reduced UVB-induced DNA damage, and decreased melanin on a reconstructed pigmented skin model.

Typical real world usage sits around 0.5-5% (and 1-2% is common for daily serums).

Amounts up to 30% have been shown to be non-irritating on human skin samples, but two isolated cases reported allergic contact dermatitis so a patch test is sensible if you have reactive skin.

Its headline job is hydration.

The star polysaccharide in aloe, acemannan, is a humectant that retains moisture and helps reduce trans-epidermal water loss.

Aloe also has real soothing credentials; it contains anti-inflammatory compounds like bradykinase and C-glucosyl chromone that help calm irritation and redness.

On the repair side, lab work shows that acemannan wakes up your skin's repair cells (fibroblasts), prompting them to multiply and speed up healing.

There's some human data for cosmetic benefit too: a cream containing 10% Aloe Barbadensis leaf extract improved skin hydration and elasticity in a real-use study.

Safety-wise, this ingredient is well-regarded with just one rare downside; there have been some case reports of acute eczema, contact urticaria, and dermatitis in people who applied aloe-derived ingredients topically. Those with a known aloe or Liliaceae sensitivity should patch test.

Typical use levels range widely, from under 1% up to 90%+ depending on the format and the effect you are after.

Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

Fun fact: Mannitol can be found in foods as a sweetener. It can be naturally found in mushrooms, algae, fruits, and veggies.

Due to its large molecule size, it doesn't penetrate beyond the skin's surface.

This ingredient has a solid regulatory track record; the CIR Expert Panel first concluded it was safe for use in cosmetics at concentrations up to 100% in 1997. A 2012 reassessment reaffirmed that finding. Safety studies have also found no irritation or evidence of toxicity.

A 2019 study did find this ingredient to grow Malassezia, so this ingredient may not be fungal acne safe.

Recent research shows topical glycogen can help improve skin moisture, support barrier function, and increase the rate of keratinocyte production. Some studies also suggest this ingredient can protect our skin from oxidative stress.

Biologically, animals and some microorganisms use glycogen as an energy-storage molecule.

This ingredient is usually derived from marine or plant sources, but can sometimes come from animals. We recommend reaching out to the brand if you have questions about the source of their glycogen.

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

For instance, Habanolide is a proprietary trade name for a specific aroma chemical. When used as a fragrance ingredient in cosmetics, most aroma chemicals fall under the broad labeling category of “FRAGRANCE” or “PARFUM” according to EU and US regulations.

The term 'parfum' or 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term.

For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance by INCI standards.

One example is Calendula flower extract. Calendula is an essential oil that still imparts a scent or 'fragrance'.

Depending on the blend, the ingredients in the mixture can cause allergies and sensitivities on the skin. Some ingredients that are known EU allergens include linalool and citronellol.

Parfum can also be used to mask or cover an unpleasant scent.

The bottom line is: not all fragrances/parfum/ingredients are created equally. If you are worried about fragrances, we recommend taking a closer look at an ingredient. And of course, we always recommend speaking with a professional.

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.

This is why Europe's medicines regulator has approved calendula extracts as a traditional remedy for minor skin inflammation and healing small wounds.

The stronger human evidence is around would/ulcer care rather than everyday cosmetic claims; a review that pulled together 14 studies found that calendula helped calm the early, inflamed stage of a wound and helped new skin tissue form faster.

Two studies also showed it shrank leg ulcers (the kind caused by poor circulation). Results were mixed for burns and for the skin irritation people get from radiation treatment, so it's not a sure thing there.

In cosmetics, it's mostly a skin conditioning and soothing agent.

The Cosmetic Ingredient Review panel concluded that calendula-derived ingredients are safe as used and that the ingredients are not irritating, sensitizing, or photosensitizing in clinical tests (though they may be mild eye irritants).

Typical use levels are quite low; industry data reported it used at under 0.5% (one supplier noted a 10-25% extract blend used at 1-10% in the finished product). Historical use goes up to 10%.

The only thing to keep in mind is if you have daisy/ragweed allergies. Calendula is in the same family and one patch-test study found 2% of dermatitis patients reacted to marigold. Be sure to patch test if you have sensitive or allergy-prone skin.

Chelating agents help neutralize unwanted metals from affecting the formulation.

Sodium gluconate is water-soluble.

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:

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.

These compounds allow centella to dial back inflammation, encourage the skin to build and hold onto collagen, support the barrier and hydration, and bring solid antioxidant activity to protect against signs of aging.

Centella also carries a nice supporting cast of Vitamin A, vitamin C, several B vitamins, and amino acids. Put it all together and you get an ingredient that soothes, hydrates, and protects, all at once.

Most of centella's magic comes from the four big compounds (Asiaticoside, Madecassoside, Asiatic Acid, and Madecassic Acid). These are the actives doing the heavy lifting in almost every centella study.

Here is the short version of what they do in the skin:

So it is not just soothing for the sake of soothing. Centella calms the skin AND helps it rebuild.

Just FYI, not all centella on an ingredient list is the same. What you are getting actually depends on the extract:

Fun fact on the ratios: the leaves tend to be richest in Madecassoside and Asiaticoside, and lower in the two acids. The exact amounts shift with where the plant is grown and how it is processed. This means purity really does vary brand to brand.

Centella is one of the most easygoing actives out there.

It layers well with basically everything: niacinamide, hyaluronic acid, peptides, and vitamin C, and also pairs nicely with stronger actives like retinoids and exfoliating acids where it can help take the edge off irritation.

On the safety side, centella and its triterpenes are classified as weak sensitizers, meaning allergic reactions are possible but uncommon.

Patch tests at 1% and 5% came back negative in test panels, and creams at typical use levels did not cause allergic reactions across large groups of people.

But as with any new active, a patch test is still a smart move for very reactive skin.

Centella is widely used because it is effective at low percentages. For context, human safety testing found no meaningful irritation from creams containing centella extract at everyday use levels (the tested amounts were well under 1%).

The irritancy threshold in animal testing was also above 30% (so real-world formulas sit far below anything concerning).

In collagen lab studies, higher concentrations drove more collagen synthesis, so serums built around centella tend to feature it more prominently.

Bottom line: you will find centella working nicely anywhere from a fraction of a percent up to hero-ingredient levels depending on whether it is a supporting soother or the main event.

Fun fact: Centella has been used as a medicine and in food for many centuries. As a medicine, it is used to treat burns, scratches, and wounds.

The tannin in witch hazel has a drying effect when used on skin and constricts proteins. This helps minimize the look of large pores. The presence of tannins and fragrance may be sensitizing.

The catechins in witch hazel have anti-inflammatory properties while the gallic acid is antibacterial.

Indigenous groups have used witch hazel to help treat inflammation, which was then used by early settlers to North America.

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.

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.

In cosmetics, it mainly functions as a bulking agent, viscosity controller, binder, and absorbent. It helps thicken products, stabilize powders, and get certain textures a less "wet" feel.

This ingredient has a pretty solid safety profile; it's recognized as a safe food additive and its large molecular size means it doesn't meaningfully penetrate skin.

Human repeat insult patch tests using a rinse-off facial product containing 42.69% dextrin found no skin irritation or sensitization in 54 subjects.

Typical real-world usage is much lower: usually under 1% as a texture modifier and up to 40% in masks (rinse off products use less).

A 2025 review of 18 human studies found that using Ferulic Acid (0.5-1%) daily for one to three months showed improvements in:

As far as allergies go, Ferulic acid is generally well-tolerated but can cause an allergic reaction in very rare cases. It's also worth noting that Ferulic acid is often extracted from plant sources like rice bran or wheat bran, so be sure to path test if you have known grain allergies.

Outside of skincare, researchers are also looking into Ferulic Acid for its potential benefits in areas like diabetes, Alzheimer's, and heart health.

This ingredient can be found in makeup, sun care, and skincare.