Rudolph Care Nourishing Cleansing Oil

Clinical studies have found it can reduce water loss and improve smoothness/hydration, particularly in sensitive skin types. Studies also suggest it helps maintain the lipid layer that is compromised in atopic (eczema-prone) skin.

Wound healing studies showed that low-concentration linseed oil formulations (1-5%) produced significant barrier repair, but it should be noted that high concentrations showed diminishing returns.

Due to the rich fatty acid content, this ingredient may not be fungal acne safe.

Dicaprylyl Ether gives a non-greasy feel and better spreadability to products.

This makes it a great choice for spray formulations, serums, and lightweight moisturizers where traditional shea butter would be too heavy.

It's rapidly absorbed on skin and provides an instant moisturizing effect and velvety after-feel.

These conditioning benefits trace back to shea's well-studied bioactive profile; shea is rich in antioxidants like tocopherols and contains stearic and oleic acids that support skin barrier health.

It also contains triterpene alcohols known to reduce inflammation, cinnamic acid esters with some UV-absorbing capacity, and lupeol that protects skin proteins.

Research backs up those triterpenes: a study isolating triterpene acetates and cinnamates from shea fat found all tested compounds showed anti-inflammatory activity in mice.

Fungal acne: Because this is an ethyl ester derived from shea's long-chain fatty acids (primarily stearic C18 and oleic C18), in vitro testing has shown the Malassezia species can grow in the presence of ethyl esters. This ingredient may not be fungal acne safe.

In skincare, it is an emollient that dries down to a solid film with water-binding properties. This helps keep skin hydrated and helps reduce transepidermal water loss (TEWL).

A 2026 dermatology review pulls together its broader uses:

Human clinical testing found this ingredient to be non-irritating and non-sensitizing.

Because castor oil contains fatty acids in the C11-24 range, this ingredient may not be fungal acne safe.

At this time, the literature does not support castor oil in regrowing hair. A 2022 systematic review found no strong evidence that it supports hair growth and only weak evidence that it improves hair shine.

Castor oil itself carries "perfuming" and "masking" function tags according to the official CosIng database. This is because of its mild odor and odor-dampening properties.

This plant is native to the Amazon rainforest.

Squalene is pretty cool because it's already naturally found in our skin and makes up about 13% of sebum. This makes it a great moisturizing and skin-barrier-supporting ingredient.

This ingredient is typically used at low concentrations (~1-3%) and occasionally up to 25% when acting as the main ingredient in a formula.

Fungal acne note: Though this ingredient is largely free of fatty acid esters that feed Malassezia, it may still have some residual fatty acids depending on the purity. This is why this ingredient is marked as not fungal acne safe.

People with existing olive oil allergies should be cautious as well.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.