Omitted Fresh Lime Glow & Pore Refining Serum

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.

You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.

In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.

If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.

When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.

When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.

In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).

Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.

Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.

The type of niacinamide used in skincare is synthetically created.

Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.

Lab research on specialized corn kernel extracts have shown increase collagen deposition in fibroblast cell models; however, human clinical data is needed to support this.

It's pretty compatible with most ingredients, but just sure to space out enzyme products with strong acids/retinoids to avoid over-doing it.

Maximum reported concentration is around 0.1% and most leave-on products use just 0.05%. If you see higher figures like 5-10%, this is usually the pre-diluted material from raw extract suppliers.

This ingredient has an assuring safety record and there's a lack of clinical case reports of dermatitis from using it.

The only caveat is allergy: patch test if you have a papaya or latex-fruit allergy.

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

Last, the phytochemicals found in apples are strong antioxidants. These antioxidants help with anti-aging as they protect your skin cells against oxidative damage.

Grape extract also helps soothe and hydrate your skin.

Your skin has cells called fibroblasts that build collagen (the stuff that keeps skin firm and smooth). Adenosine basically flips a switch on these cells that tells them to get to work making more collagen and other proteins. These cells slow down on their own as skin ages, so Adenosine helps give them a little nudge to keep going.

The clinical backing is pretty solid too.

A blind, randomized, placebo-controlled trial of 126 women aged 45-65 tested a 0.1% cream twice daily and found real improvements in crow's feet and frown lines using a precise 3D skin-mapping technique; these changes showed up by week 3 and held at 2 months.

A later study using Adenosine-loaded dissolving microneedle patches reported gains in wrinkle depth, dermal density, elasticity, and hydration.

On concentrations, South Korea's Ministry of Food and Drug Safety has set 0.04% as the approved functional anti-wrinkle level. You'll typically see this ingredient used somewhere in the 0.04-0.1% range since it works at low doses.

This ingredient has been found safe for cosmetics with the data showing no irritation or sensitization.

Overall, this is a great ingredient for any anti-aging routine and has no photosensitizing effect, so it suits both AM and PM use.

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.

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.

Antioxidants help fight free-radicals. Free-radicals are molecules that may damage your skin cells, such as pollution.

A 2017 study found neem oil was effective at treating wrinkles and dry skin in mice. The study also found higher levels of elastin and procollagen.

Evidence in humans is limited to the non-root parts of this plant; topical arctium fruit extract showed improvements in dermal extracellular matrix metabolism and visible wrinkles.

Evidence for mint as a "treatment" ingredient is limited and depends heavily on the specific extract type and concentration.

In large percentages, peppermint extract may sensitize the skin.

The only catch is that HA isn't a single thing; it actually comes in a wide range of molecular weights (~50 - 2,000+ kDA) and size matters.

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

This is why the best HA serums blend the two sizes together so you get the best of both worlds.

The majority of cosmetic HA is produced by bacterial fermentation, typically using Streptococcus or Bacillus strains. Typical use levels in skincare sit around 0.1-2%.

A clinical study using a 0.2% low-molecular weight HA gel showed improvement in facial seborrheic dermatitis with excellent tolerance.

These are some other common types of Hyaluronic Acid:

Because hydrolyzed hyaluronic acid is smaller in size, it can slip past your outermost layer of skin more easily than full-sized HA.

Most formulations will combine all sizes to get the best of both worlds.

Typical usage levels range from 0.01-1%. Any percentage higher than 2% might become goopy and tacky.

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.

Studies also show that it has antifungal activity against Malassezia furfur. This is the yeast that causes conditions like dandruff, seborrheic dermatitis, and folliculitis (fungal acne). It also displays anti-inflammatory activity.

On top of all this, all tested fractions of the extract demonstrated significant tyrosinase inhibitory activity comparable to ascorbic acid. This suggests it can play a potential role in fading hyperpigmentation.

A 2020 study found the phenolics of this root to have an anti-inflammatory effect.

Fun fact: This ingredient is used in traditional Asian medicine.

It's worth knowing sugars are already a natural component of the skin's NMF (natural moisturizing factor) so it's a molecule that your stratum corneum is well-acquainted with.

Just so you know, glucose is hydrophilic (water-loving) and the stratum corneum is a strong barrier to hydrophilic compounds. This just means penetration is slow and most of the action is happening on the surface.

Gram-to-gram, glucose is not as efficient as a humectant as glycerin. This is why you'll likely see glycose paired with stronger humectants for a bigger hydration payoff.

In skincare, glucose is typically derived from corn or other starch sources.

Like salicylic acid, this ingredient is a chemical exfoliant that can help break down the oil in your pores and reduce inflammation.

Though studies for LHA do show it to be less effective than salicylic acid. To be fair, salicylic acid is the reigning monarch of acne treatments.

However, a study from 2009 found LHA to be comparable to BPO, making it a good alternative for people with sensitive skin. Another study of 14 patients found a significant decrease in comedones after using LHA.

Another pro of LHA? It is less irritating than salicylic acid due to its large molecule size.

Large molecules cannot penetrate skin as well, so they are gentler on the skin. LHA is much less penetrative than salicylic acid.

An in-vitro study (not done on a living organism) found only 6% of LHA penetrated past the statum corneum compared to 58% of salicylic acid. An in-vivo (done on a living organism) analysis revealed ~17% of LHA was still present in the top layer of skin after 4 days, versus ~9% of salicylic acid.

Interestingly, a study from 2008 found LHA comparable to another famous acid, glycolic acid.

This study found about 10% of LHA is as effective as 20-50% of glycolic acid in treating hyperpigmentation and fine-lines.

Hydroxy acids have been found to stimulate skin protein, lipids, and thermal thickening. This may have anti-aging benefits.

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.

It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.

Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.

A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.

This matters a lot because a lot of actives (like vitamin C) needs a specific pH to work well and feel comfortable on skin.

Concentration use ranges from 0.1-1.0% depending on the formula.

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%.

These flowers are rich in polysaccharides, protein, amino acids, catechins, and saponins.