Herbivore Milky Way 10% AHA + Oat Soothing Exfoliating Serum Versus Goop Beauty Goopglow Dark Spot Exfoliating Sleep Milk

PHAs are more gentle than AHAs due to their larger structure. They do not penetrate as deeply as AHAs and take a longer time to dissolve dead cells. Studies show PHAs do not cause as much irritation.

Gluconolactone has some interesting properties:

In a 2004 study, Gluconolactone was found to prevent UV damage in mouse skin cells and has not been found to increase sun sensitivity. However, we still recommend wearing SPF daily.

This ingredient is is an created by reacting gluconic acid with an alcohol.

As a humectant, it helps the skin stay hydrated by pulling moisture to your skin. The low molecular weight of glycerin allows it to pull moisture into the deeper layers of your skin.

Hydrated skin improves your skin barrier; Your skin barrier helps protect against irritants and bacteria.

Glycerin has also been found to have antimicrobial and antiviral properties. Due to these properties, glycerin is often used in wound and burn treatments.

In cosmetics, glycerin is usually derived from plants such as soybean or palm. However, it can also be sourced from animals, such as tallow or animal fat.

This ingredient is organic, colorless, odorless, and non-toxic.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

On the other hand, emulsifiers prevent ingredients (such as oil and water) from separating.

Glycolic acid removes the top layer of dead skin cells to allow newer and fresher ones to emerge.

AHAs work by breaking down the structural “glue” that holds old skin cells in place. When that buildup is gone, your skin can renew itself more efficiently.

Research also shows glycolic acid stimulates collagen production, helping to firm and thicken the skin over time. This is one of its biggest advantages over other AHAs.

Overall, glycolic acid helps with:

Fun fact: Glycolic acid boosts skin hydration by helping it produce molecules that increase hyaluronic acid naturally.

To work best, glycolic acid products should have a pH between 3-4 (that’s where exfoliation is most effective but still gentle on skin).

The pH and concentration of a product are key to its effectiveness:

It is normal to feel a slight stinging sensation when using glycolic acid. This usually fades as your skin adjusts.

Because glycolic acid has the smallest molecular size in the AHA family, it can penetrate deeper, which enhances its effectiveness but also makes it more likely to irritate sensitive skin.

If your skin is very sensitive or prone to rosacea, glycolic acid may be too strong; in that case, try milder options like lactic acid or a PHA instead.

Recent studies suggest glycolic acid might even help protect against UV damage. But don’t skip sunscreen! Freshly exfoliated skin is more sensitive to the sun.

Glycolic acid is a skincare superstar. It smooths, brightens, hydrates, and firms the skin. Unless you’re highly sensitive, it’s well worth adding to your routine.

Read more about some other popular AHA's here:

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:

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

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

It also contains Vitamin E, a great moisturizing ingredient. Vitamin E is also an antioxidant and protects your skin against oxidative damage.

This ingredient humectant properties, meaning it helps draw moisture from the air. This helps keep your skin hydrated.

While jojoba has antibacterial properties, it is only able to kill some strains of bacteria.

Studies also show it helps in wound healing. In fact, Indigenous cultures have used jojoba as a moisturizer and to help treat burns for centuries.

Fun fact: Jojoba oil similar to natural human skin sebum, so it has a great effect on dry skin. It is also promising with helping to regulate sebum production.

Due to its fatty acid content, Jojoba oil may not be fungal acne safe. We recommend speaking with a professional if you have any concerns.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

Squalane comes from squalene, which occurs naturally within the sebum of our skin. It is one of the oils our skin produces to keep itself hydrated. Squalane is the hydrogenated version of squalene and has a longer shelf life.

Research shows that squalane is non-irritating (even at 100% concentration).

In general, it's a fantastic ingredient. It does a great job at hydrating the skin, and it's suitable for those with sensitive skin.

The source of squalane may impact malassezia / fungal acne. This is because olive oil derived squalane can contain impurities such as fatty acids and plant waxes. Sugarcane derived squalane is recommended for anyone with malassezia concerns.

Is squalane vegan?

This depends on the source. Squalane can be derived from both plants and animals. Most squalane used in skincare comes from plants.

Please note: the source of squalane is only known if disclosed by the brand. We recommend reaching out to the brand if you have any questions about their squalane.

Read more about squalene with an "e".

Is squalane an oil?

Squalane is often called an oil, but it’s technically not; it’s a hydrocarbon, meaning it’s only made of carbon and hydrogen, unlike true oils which are triglycerides made of fatty acids and glycerol.

The term “oil-free” isn’t regulated, so companies can define it however they want. Some exclude all oils, while others just avoid mineral oil or comedogenic oils.

While some people avoid oils thinking they cause breakouts, the right kind of oil (or oil-like ingredient like squalane) can actually help balance and hydrate your skin. It’s worth testing out simple oils or squalane to see what works best for your skin.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Stay hydrated!

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.