Skin Resource.MD Age-Limit Advanced Refinishing Serum

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:

High percentages of Sodium Lactate can have an exfoliating effect.

Fun fact: Sodium Lactate is produced from fermented sugar.

This property also makes Pentylene Glycol a great texture enhancer. It can also help thicken or stabilize a product.

Pentylene Glycol also acts as a mild preservative and helps to keep a product microbe-free.

Some people may experience mild eye and skin irritation from Pentylene Glycol. We always recommend speaking with a professional about using this ingredient in your routine.

Pentylene Glycol has a low molecular weight and is part of the 1,2-glycol family.

As an emollient, it helps trap moisture in the skin. It is considered an occlusive.

This ingredient contains polyphenols, a strong antioxidant. Antioxidants help fight off molecules that damage skin cells.

On top of that, the antioxidants in green tea neutralize free-radicals from the sun. This gives the skin some extra UV protection, but should not replace sunscreen.

Many components of tea have anti-inflammatory properties.

Polyphenols and L-theanine help soothe the skin and reduce irritation. The caffeine in Camellia Sinensis Leaf Extract helps calm inflamed blood vessels.

Other compounds found in tea include: Vitamin Bs, linoleic acid, magnesium, calcium, iron, and zinc.

Research has shown both drinking Camellia Sinensis Leaf Tea and applying it to the skin can help boost skin elasticity and hydration. Studies also show using tea extract may reduce sebum, or oil, production.

Arginine isn't fungal acne safe when used in the presence of other lipids (fats, fatty acids, oils, esters, etc). Oils and fats occur naturally within the skin, so take caution when using Arginine if you're prone to fungal acne.

It is also an emollient. Emollients help soften the skin and prevent water loss. Silicones create a silky texture in products. D5 helps other ingredients become more spreadable.

Studies show D5 is safe to use in skincare products. We recommend speaking with a skincare professional if you have concerns.

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.

Due to their hygroscopic nature, they act as both humectants and emollients. Humectants draw moisture from the air to your skin, while emollients help trap moisture in.

The phospholipids in our skin can be naturally depleted. Replenishing the phospholipids in our skin can help hydrate your skin.

Studies show phospholipids display antioxidant activity and may help with reducing the signs of aging.

This ingredient is non-occlusive.

Some types of phospholipids:

This ingredient can also be found in pill medicines to help our bodies digest other ingredients.

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.

Learn about other types of clay, such as Kaolin, Bentonite, or Fuller's Earth.