innisfree My Hair Recipe Essential Hair Oil Serum

You'll likely see this in many BHA products because this is the go-to solvent for salicylic acid.

This ingredient is typically used at levels between 2-20%.

Regarding fungal acne:
In 2019, this ingredient was tested against multiple Malassezia species (the yeast that causes fungal acne) and showed no growth.

That profile makes it a classic emollient; it works by hanging out with the skin's surface lipids, softens, and slows down water loss.

The most cited study on it was done on skin cells in a dish where this oil got them to make more of the building blocks for collagen while also slowing down the enzyme that breaks collagen down. Researchers tested this on human skin too; it didn't cause irritation and helped skin hold onto moisture better.

Another study done on cells and mice found this oil quieted down some of the body's inflammation signals.

These studies are still small, early, and not done on humans, so it's best to think of this ingredient as a great supporting ingredient for the rest of your routine and not the main active.

Concentrations can range from 1-5% in serums to 100% as a single face oil (how it's most traditionally used).

Because this ingredient is a triglyceride of long-chain fatty acids, this ingredient may not be Malassezia safe.

Allergies to this protein are quite rare as the refined seed oil contains very little residual protein. Human irritation testing also came back clean. But it is a plant and as with any botanical ingredient, contact allergy is possible.

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.

One manufacturer study found their glycolipid also demonstrated sebum reduction and helped reduced oiliness after four weeks. This means it can also be great for scalp care.

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.

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

Studies show products formulated with NMF ingredients help strengthen our skin's barrier. Having a healthy skin barrier reduces irritation and increases hydration. Our skin barrier is responsible for having plump and firm skin. It also helps protect our skin against infection, allergies, and inflammation.

Fun fact: Phytosphingosine is abundant in plants and fungi.

More ingredients that help boost collagen in skin:

A separate study found the flower extract had solid antioxidant activity and reduced the reactive oxygen species that urban air pollution triggers in skin cells.

Newer work also points at anti-aging and calming effects:

One 2025 paper tied the extract and its component hyperoside to collagen III and elastin production plus better skin-barrier protein expression. A mouse study on eczema-like skin found four weeks of topical camellia extract reduced inflammation and itch-related markers.

Just know that most of these studies are cell-culture and animal work and not human trials. For now, it's best to treat it as a nice supporting antioxidant rather than a headline active.

At this time, there's no published regulatory use-level for this specific ingredient; suppliers usually sell it as a water/glycerin-based extract used in the low single-digit percent range.

There's no published contact-allergy case reports for this ingredient but as with any botanical, a patch test is sensible if you react to plant extracts generally.

Lab work shows that a butylene glycol extract of young camellia leaves mopped up radicals, reduced protein damage in the stratum corneum after UVB exposure, and lowered free-radical levels inside culture skin cells.

Another related whole-plant extract calmed inflammatino and boosted the skin's own antioxidant enzymes in a mouse eczema model.

Concentration uses typically range from 0.1-5% as a botanical extract.

There are no published case reports of allergic contact dermatitis to this ingredient and one report noted that camellia leaf extracts are used topically without reported irritation issues. But like any botanical extract, patch testing is sensible if you react to plant extracts generally.

On allergies: there are no published case reports of allergic contact dermatitis to this ingredient, and one review notes camellia leaf and flower extracts are used topically without reported irritation issues; the theoretical concerns are its tannins and saponins, which can be sensitizing at high levels, so patch testing is sensible if you react to plant extracts generally, but the risk looks low.

This ingredient is an emollient, emulsifier, and penetration enhancer. As an emollient, it helps soften and hydrate skin by trapping moisture within. As an emulsifier, it prevents oil and water ingredients from separating.

Hydrogenated Lecithin can form tiny spherical structures made of phospholipid bilayers called liposomes. These liposomes are able to capture compounds inside their structure and deliver them through the skin barrier.

Because phospholipids are a natural component of our cell membranes, this ingredient is inherently compatible with skin.

A 2021 study found lecithin-based surfactants were less harsh and more tolerable comared to Sodium Lauryl Sulfate (SLS).

This ceramide works by slotting into gaps within the stratum corneum's lipid matrix to limit trans-epidermal water loss (TEWL) and shield the skin against external irritants.

A study with 312 patients found that using a ceramide-containing routine for 4 weeks reduced the severity of atopic dermatitis by over 61%.

Another clinical study in subjects aged 60 and older found that a ceramide body wash and moisturizer improved skin dryness and itchy skin in 15 days.

Overall, ceramides are considered non-irritating and safety tests have found little to no observable adverse effects from using this ingredient.

Ceramide NP is usually sourced from plants (like soybean or rice bran), or produced synthetically.