In Practice Skincare Skin Boost 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.

According to the manufacturer, this peptide boosts the skin's immune defenses and regenerates the outer layers of skin.

On the surface, it acts as a humectant that holds water in place and reduces moisture loss for a plumper, smoother feel, while its anti-inflammatory and antioxidant properties make it a great pick for calming redness or sensitive skin

The more interesting story is underneath:

Despite its large molecular size, oat beta-glucan has been shown to penetrate the epidermis and reach the dermis by slipping between skin cells. Here, it interacts with fibroblasts and macrophages to nudge collagen synthesis and support wound repair.

A small 2005 split-face clinical study of 27 subjects found topical beta-glucan produced measurable reductions in wrinkle depth, height, and roughness after 8 weeks of use.

It is worth noting the trial was small and the penetration testing used frozen, irradiated skin so the anti-aging data is encouraging rather than definitive.

This ingredient gets along with pretty much everything and is typically used around 0.1-1%.

Fungal acne: This ingredient is not a food source for the Malassezia yeast because it is a glucose polysaccharide with no fatty acid or ester component.

The small peptides and amino acids (including Natural Moisturizing Factor components like Hydroxyproline, Serine, and Aspartic Acid) help the surface of the skin hold onto water, feel softer, and look temporarily plumper.

This ingredient also has mild film-forming and antioxidant properties with research showing the antioxidant effect is stronger the lower the molecular weight of the peptides.

It's worth being realistic here:

Topically applied Hydrolyzed Collagen conditions the upper layers of skin rather than rebuilding the structural collagen deep in your dermis (the wrinkle-and-firmness benefits people associate with Collagen mostly come from oral supplements in studies, not topicals).

However, recent lab and skin-model work on Hydrolyzed Fish Collagen has shown promising effects on cell viability and wound healing when used as an active.

Typical concentrations range from 0.2-2%, but the percentage can go much higher in rinse-off or hair products (sometimes even above 50%).

Clinical studies on this ingredient showed no irritation, sensitization, or phototoxicity.

If you are looking for vegan collagen, it usually goes by a different INCI name like hydrolyzed soy protein. Vegan collagen is derived from yeast, bacteria, or plant sources.

The results are varied.

A study from 2021 found hydrolyzed collagen increased elasticity and improved wrinkles in 1,125 participants between age 20 and 70. Another study found increased skin thickness in participants between the ages of 45 to 59.

However, It is difficult to prove that oral collagen will end up working on your skin. Many of the studies using hydrolyzed collagen also add several vitamins and nutrients into the test mixture as well.

Further studies are needed at this time.

D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.

Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):

Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.

This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.

Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.

This ingredient is also referred to as pro-vitamin B5.

The good news is: studies show applying this ingredient topically replenishes ubiquinone levels in our skin. This also comes with a ton of skin benefits. These benefits include:

Ubiquinone is considered a large molecule and cannot be absorbed into the lower layers of skin. This is why it is believed to be such an effective antioxidant: it protects our skin in the upper layers and prevents damage in the deeper layers.

When used in sunscreen, ubiquinone is shown to increase ingredient stability, increase SPF factor, and add to infrared protection.

Fun fact: ubiquinone is fat-soluble.

Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.

A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.

Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.

One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.

Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.

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:

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:

Copper has wound healing properties due to its role in creating new blood vessels and tissue repair.

Antioxidant components in chamomile make it an effective ingredient to help slow the signs of aging. Antioxidants help fight free-radical molecules, or molecules that may damage your skin.

Essential oils from chamomile have been found to improve wound healing due to its antimicrobial properties.

Ancient Greeks and Egyptians used Chamomile to treat skin redness and dryness. Chamomile has also been used to help treat stomach issues.

It doesn’t protect you from the sun, but it can help your skin bounce back after too much time in it.

Let’s get into the details:

Aloe contains antioxidant Vitamins A, C, and E, which help fight off free radicals (unstable molecules from things like pollution that can damage your skin).

It’s also rich in polysaccharides, which are natural sugars that help hydrate the skin by acting like the skin’s own moisturizing agents. These, along with other sugars like monosaccharides, help form a protective barrier that locks in moisture.

Aloe works as both a humectant and an emollient. That means it draws water into the skin (humectant) and helps trap it there (emollient), making it an effective natural moisturizer.

You’ll also find a mix of other skin-supporting ingredients in aloe, including folic acid, choline, calcium, amino acids, fatty acids, and even Vitamin B12.

Out of the 420+ species of aloe, Aloe barbadensis is the most widely used in skincare products thanks to its gentle yet effective properties.

There are over 420 species of aloe but Aloe Barbadensis is the most commonly used for topical products.

These fatty acids make it a solid choice for supporting the skin barrier and softening skin.

On the evidence front, a 2024 review on postsurgical scarring found this ingredient to be safe with benefits for scar redness, texture, and pigmentation. It's worth noting the human data is still limited and more trials are needed so it's reasonable to be optimistic but not expect miracles.

This ingredient has been found safe in current practices of use and concentration, with the only caveat that it could contain fragrance allergens (linalool and eugenol).

Fungal acne: The fatty acids of this oil fall into the C11-24 range that Malassezia yeast can metabolize, so this ingredient may not be fungal acne safe.

This oil is rich in fatty acids, including: two types of linoleic acid (~30-34%), oleic acid (17%), and palmiteic acid (35%). Note these numbers are averages, and different parts of the plant will vary.

Palmitoleic acid has been shown to help soothe inflammation and promote wound healing. It is also naturally found in the fat of our skin.

Overall, seabuckthorn oil is great for nourishing, hydrating, and soothing skin. While it shows UV protecting properties, it should not replace sunscreen.

Due to the rich fatty acid content, this ingredient may not be Malassezia folliculitis, or fungal acne, safe.

Seabuckthorn berries are little orange fruits. This plant is native to Asia.

The gamma-linoleic acid (GLA) is the headliner here; it's relatively rare in plant oils and acts as a precursor for anti-inflammatory signaling molecules in the skin.

There's a mixed body of clinical research with this ingredient as well, mostly on eczema/atopic dermatitis skin.

Some controlled trials showed improvement in inflammation, dryness, scaling, and overall severity. Other studies and large meta-analysis failed to show a significant effect; the honest takeaway here is "promising but inconsistent" rather than "miracle oil".

On the safety front, this ingredient is found to be safe as used in cosmetics and even has a history of safe food use.

Since this oil is contains oleic acid and palmitic acid, it may not be fungal acne safe. The Malassezia yeast feeds on fatty acids with carbon chain lengths between C11-C24. Oleic Acid sits at C18 and Palmitic acid sits at C16.

In vitro studies have shown that oleic acid and palmitic acid are some of the fatty acids that induce rapid Malassezia growth in lab settings.

Unlike other plant oils, jojoba wax doesn't easily penetrate skin. It mostly works in the uppermost layers as an emollient. This just means it forms a light barrier on the skin to help retain moisture.

Formulations with jojoba esters up to 90% reduced transepidermal water loss (TEWL) and increased barrier recovery by 81% (outperforming bisabolol at 47%).

Besides barrier support, the science also suggests jojoba to have anti-inflammatory effects and potential applications for skin infections, aging, and wound healing.

Fun fact: Indigenous cultures have used jojoba as a moisturizer and to help treat burns for centuries.

Fungal acne: The Malassezia yeast is known to metabolize fatty acids in the C11-24 range and jojoba's dominant fatty acid components fall into this range. This ingredient may not be fungal acne safe.

As an emollient, it softens and hydrates skin by forming a thin barrier that locks in moisture.

Clinical studies have found it to be non-irritating and non-sensitizing. The CIR Expert Panel has evaluated the available safety data and concluded it is safe for topical use.

Because of the oleic acid content, this ingredient may not be fungal acne safe.

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.

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

As a humectant, Sorbitol helps draw water to the skin. This helps keep the skin hydrated. Sorbitol also helps create a thicker texture in products. You might find sorbitol in your toothpaste and other gels.

It is a non-irritating ingredient that is great for those with dry skin.

Sorbitol is a prebiotic. It helps promote the growth of healthy bacteria on your skin. The bacteria on your skin form a microbiome. This microbiome helps protect your skin from infection and harmful bacteria.

Studies show green tea extract and its catechins (like epigallocatechin gallate (EGCG)) help your skin cells product energy more efficiently and reducing the number of free-radicals that can damage your skin from the inside.

In lab-grown skin models, this translated to younger, healthier, and stronger skin.

There's also good sun protection data; researchers saw less DNA damage and redness on human skin when green tea was applied before UVB exposure. And the more they applied, the better the protection.

Needless to say, this ingredient shouldn't replace your sunscreen. But it is a great supportive ingredient that you can already find in many sunscreens and antioxidant serums.

A 2009 study found a 2% green tea lotion was effective for mild-to-moderate acne thanks to its anti-inflammatory and mild antimicrobial activity.

The quality of the extract matters a lot here:

Good extracts contain 50-90% catechins while lower quality ones are mostly there for marketing. We recommend reaching out to the brand if you have questions about the quality or source of their ingredients.

Human Repeated Insult Patch Testing showed no irritation or sensitization at use concentrations (0.86% in leave-on products and up to 30% as leaf water).

On top of that, soybean oil is rich in vitamins like vitamin E, a potent antioxidant.

Research on soybean's active components also point to anti-inflammatory, collagen-stimulating, antioxidant activity, and protection against UV-induced oxidative damage.

Most of this research applies to the broader soybean plant and not just the oil fraction alone.

This ingredient may not be fungal acne safe due to the oleic acid content.

A clinical study found that applying 0.5% bisabolol daily for 8 weeks produced an average 9% decrease in skin pigmentation. Researchers found it can also suppress the process that leads to excess melanin production in skin.

In vitro studies found that bisabolol combined with propylene glycol significantly increased skin permeability by increasing lipid fluidity in the stratum corneum.

You'll likely see use concentrations quite low, usually 0.1-0.2%.

Overall, this is a well-tolerated ingredient that works well in formulas designed for sensitive, reactive, or post-procedure skin.

It helps with dark spot fading by interfering with the process of skin darkening, helping to reduce hyperpigmentation. Like other forms of vitamin C, this ingredient encourages the skin to create more collagen.

As an antioxidant, it helps fight free-radicals. Free-radicals are molecules that may damage your skin cells.

One study found Ascorbyl Tetraisopalmitate to degrade in sunlight, but is stabilized when combined with acetyl zingerone.

This ingredient has skin conditioning, anti-inflammatory, and humectant properties. Humectants help hydrate your skin by drawing moisture from the air. This helps keep your skin moisturized.

First, Retinyl palmitate is created from palmitic acid and retinol. It is a retinol ester and considered one of the weaker forms of retinoid.

This is because all retinoids have to be converted to Tretinoin, AKA retinoic acid. Retinyl Palmitate is pretty far down the line and has to go through multiple conversions before its effects are seen.

Due to this long and ineffective conversion line, the benefits of Retinyl Palmitate are debated.

Studies show Retinyl Palmitate to help:

Dermatologists say this ingredient is ineffective because it isn't used in high enough concentrations in cosmetics.

This ingredient used to be found in sunscreens to boost the efficacy of sunscreen filters.

The downfall of Retinyl Palmitate was due to released reports about the ingredient being correlated to sun damage and skin tumors.

While there is a study showing this ingredient to cause DNA damage when exposed to UV-A, there is no concrete proof of it being linked to skin cancer. It is safe to use when used correctly.

All retinoids increase your skin's sensitivity to the sun in the first few months of usage. Be especially careful with reapplying sunscreen when using any form of retinoid.

Currently, this ingredient is still allowed in cosmetics all over the world. In Canada, cosmetics must have a warning label stating the product to contain Retinyl Palmitate

Fun fact: This ingredient is often added to low-fat milk to increase the levels of Vitamin A.

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.

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

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.

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.

It plays well with most ingredients and is typically used at 0.1-1%. However, concentrations up to 50% have been reported in moisturizers.

As an emulsifier, Sclerotium Gum helps prevent ingredients from separating, such as water and oil.

Due to it being edible and tasteless, you'll likely find this ingredient in breath freshener strips. This ingredient is produced from the starch of the fungus, Aureobasidium pullulans.

Pullulan is stable over a broad-range of pH.

The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.

Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).

True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.

Because it is derived from lauric acid, it may not be fungal acne safe.

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

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.

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:

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.

The way it works is worth understanding; benzoic acid works when the formula is acidic. It is able to sneak into a microbe's cell and mess up how it functions to stop it from growing in an acidic product.

However, the acid switches to an inactive form and stops working if a product isn't acidic enough (above ~5 pH). This is why you'll often see it in low pH products or teamed up with other preservatives to cover the gap.

Safety wise, it's one of the better studied preservatives out there.

The Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe for use in cosmetic formulations at concentrations up to 5%.

A large international review found this ingredient had no effects on the human body and had low irritation potential.

Just so you know, real world use is usually much lower than the 5% ceiling (usually 1% of less).

The EU caps it at 2.5% in rinse-off products, 1.7% in oral care, and 0.5% in leave-on products.

One thing worth mentioning (it's nothing to worry about): some people get a little stinging or flushing where they apply it. This isn't a true allergy; it's a temporary and harmless reaction. This is the same kind of mild tingle you might notice from sorbic acid.