SLMD Salicylic Acid Cleanser

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.

This ingredient also helps improve the spreadability of a product.

This ingredient hasn’t been shown in studies to feed fungal acne yeast.

Vitamins C and E are potent antioxidants and may help with anti-aging. The fatty acids are emollients that help soften and hydrate your skin.

Another potent vitamin found in rosehip is Vitamin A, or retinol. Retinol encourages collagen production in the skin.

Rosehip extract may help with brightening the skin. Several components, such as beta-carotene, are able to reduce pigmentation caused by sun damage.

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.

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.

The antioxidant properties help protect your body from free-radicals. Free-radicals are molecules that may damage your skin cells. As a result, ginger may help slow down signs of aging such as hyperpigmentation and wrinkles.

Studies show ginger inhibits the enzyme that breaks down collagen. It also helps with:

This ingredient has no negative side-effects and is safe to use unless one has a specific allergy to it.

Ginger originates from Southeast Asia but has spread throughout the world. It is now a common spice used in many cultures.

The cellulose and fiber in colloidal oatmeal help reduce inflammation. This can also help the skin feel softer.

Colloidal Oatmeal is also an antioxidant. Antioxidants protect our skin from free-radical damage.

Oatmeal also contains beneficial compounds:

This ingredient is created by mixing grounded oatmeal and a liquid base.

Saccharomyces is also known as brewer's yeast and was traditionally used to make beer.

It is able to lift away oil and grime and make a nice lather without stripping your skin, so it's a good pick for sensitive skin.

Safety-wise, it has a good record. The CIR Expert Panel has concluded this ingredient to be safe in cosmetics and concentrations go up to 11% in leave-on products or 13% in rinse-off products.

Despite being derived from coconut oil, this ingredient is fungal acne safe. It's a water-soluble surfactant with no fatty oils or esters left intact on skin for the Malassezia yeast to feed.

Salicylic acid is also known for its soothing properties. It has a similar structure to aspirin and can calm inflamed or irritated skin, making it a good option for acne-prone skin that is also sensitive.

Concentrations of 0.5-2% are recognized by the U.S. FDA as an over-the-counter topical acne product.

It can cause irritation and/or dryness if one's skin already has a compromised moisture barrier, so it's best to focus on repairing that before introducing this ingredient into your routine.

While salicylic acid does not increase sun sensitivity, it’s still important to wear sunscreen daily to protect your skin.

If you are looking for the ingredient called BHA or Butylated Hydroxyanisole, click here.

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.

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).

Research shows it can encourage your skin cells to turn over and renew by stimulating keratinocyte and fibroblast proliferation.

It also has mild keratolytic properties to help loosen and shed dead skin cells without being harsh.

Studies also suggest allantoin can help calm inflammation by dialing down some of the chemical signals your skin sends out when it is irritated.

This ingredient is typically used in the 0.1-0.5% range, and the FDA recognizes it as a skin protectant in OTC products up to 2%.

Overall, allantoin is a wonderful addition to most routines; it is stable across a wide pH range (~4-8), works well with other ingredients, and is considered non-sensitizing/non-irritating.

Fun fact: Allantoin is naturally occurring in comfrey root, beets, chamomile, and wheat sprouts. Our bodies even produce it as a byproduct of uric acid metabolism.

Menthol also has antimicrobial properties.

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.

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%.

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

Using high concentrations of Potassium Hydroxide have shown to irritate the skin.