COSRX The 6 Peptide Skin Booster Serum Versus MEDI-PEEL Peptide 9 Aqua Essence Toner

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.

Fun fact: Betaine is naturally created in the skin and body. The kind found within cosmetic products can be either plant-derived or synthetic.

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.

Though Caprylyl Glycol is an alcohol derived from fatty acids, it is not the kind that can dry out skin.

This ingredient is also used as a preservative to extend the life of products. It has slight antimicrobial properties.

While studying wound healing, researchers noticed GHK-Cu stimulated hair follicle enlargement and growth by keeping hair in its active growth phase longer. This has made it a promising ingredient for hair regrowth treatments.

Some people have reported increased facial hair. While GHK-Cu can make your hair follicles bigger, it usually doesn’t turn soft, barely-visible facial hairs into thick, dark ones.

Anecdotal reports suggest that overusing copper peptides might lead to premature aging due to excess free copper or enzyme imbalances. This claim isn’t backed by large-scale studies.

Unfortunately, there are limited human studies for this ingredient. While early results are promising, many studies are either small, in-vitro, or not rigorously controlled.

For example, there is a 1998 study that explored the effects of copper tripeptide, vitamin C, tretinoin, and melatonin on skin repair and collagen synthesis.

After one month, increased procollagen production was seen in 7 out of 10 participants using copper tripeptide (more than those using vitamin C, melatonin, or tretinoin.

While the study was exploratory, it offers early evidence that copper tripeptide may support collagen production. Larger, well-designed trials are still needed to confirm its potential and understand individual responses.

Read more about other common types of peptides here:

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.

Sodium Hyaluronate is naturally occurring in our bodies and is mostly found in eye fluid and joints.

These are some other common types of Hyaluronic Acid:

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.

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!