California Naturals Classic Clean Shampoo

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.

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.

Aloe Barbadensis Leaf Juice also contains sugars. These sugars come in the form of monosaccharides and polysaccharides, folic acid, and choline. These sugars are able to help bind moisture to skin.

It also contains minerals such as calcium, 12 anthraquinones, fatty acids, amino acids, and Vitamin B12.

Preclinical research has found that topical avocado oil increased collagen synthesis and reduced inflammation during wound healing, giving it some skin-repairing credibility.

The unsaponifiable fraction of the oil is also interesting: studies on avocado unsaponifiables showed that it helped skin produce more collagen and other structural compounds that support healing.

The CIR Expert Panel has found this ingredient to be non-irritating in formulations.

It's a great ingredient for dry or compromised skin. Just know it may not be fungal acne safe. This is because the oleic acid content falls within the range that Malassezia can use as a food source.

Glycolic acid is a derivative of sugarcane. While glycolic acid is an AHA with exfoliating properties, sugarcane is not an AHA.

A study from 2021 found the compounds in sugarcane extract to have antioxidant, antimicrobial, and anti-inflammatory activity. The study also suggests these compounds can inhibit skin ageing enzymes and promote collagen synthesis.

The reason this ingredient is so effective is because it forms a thin film on the skin that reduces transepidermal water loss (TEWL) while supplying linoleic acid to the stratum corneum to improve barrier strength.

The high linoleic acid content is particularly noteworthy for acne-prone skin.

Research suggests that acne-prone skin tends to be deficient in linoleic acid in sebum. Topical application may help replenish this to support a healthier follicular environment and less comedone-promoting sebum.

One randomized study found sunflower seed oil preserved skin barrier integrity in adult volunteers with and without atopic dermatitis (outperforming olive oil).

This ingredient is well-studied, gentle, and an effective emollient suitable for most skin types.

On fungal acne: This ingredient may not be Fungal acne (Malassezia folliculitis) safe. This is because it contains fatty acids with carbon chain lengths in the C11-C24 range.

Because lactic acid molecules are larger than glycolic acid, they don’t penetrate as deeply. This means they’re less likely to sting or irritate, making it a great choice for beginners or those with sensitive skin.

Like glycolic acid, it can:

Lactic acid also acts as a humectant (like hyaluronic acid). It can draw water into the skin to improve hydration and also plays a role in the skin's natural moisturizing factor (NMF) in the form of sodium lactate.

Studies show it can boost ceramide production to strengthen the skin barrier and even help balance the skin’s microbiome.

To get results, choose products with a pH between 3-4.

Lower strengths (5-12%) focus on surface exfoliation; higher strengths (12% and up) can reach deeper in the dermis (deeper, supportive layer) to improve skin texture and firmness over time.

Though it was originally derived from milk, most modern lactic acid used in skincare is vegan. It is made through non-dairy fermentation to create a bio-identical and stable form suitable for all formulations.

When lactic acid shows up near the end of an ingredient list, it usually means the brand added just a tiny amount to adjust the product’s pH.

Legend has it that Cleopatra used to bathe in sour milk to help reduce wrinkles.

Lactic acid is truly a gentle multitasker: it exfoliates, hydrates, strengthens, and brightens. It's a great ingredient for giving your skin a smooth, glowing, and healthy look without the harshness of stronger acids.

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.

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.

Due to the large molecule size, this ingredient is unlikely to penetrate skin.

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

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.

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.

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.