When most people hear the word “serum,” they picture something light, watery and almost weightless. So, encountering an oil-based serum can be surprising. Is it still really a serum, and will it deliver the same kind of results?
The answer is yes, although it works rather differently.
Choosing between an oil serum and a water serum is not simply a matter of preferring one texture over another. The base of a formula influences which ingredients it can carry, how those ingredients are protected and how the product interacts with your skin. For Noelani, creating the ʻIli Nani Vitamin C Oil Serum in an oil base was a deliberate formulation decision.
What is the difference between an oil serum and a water serum?
Water-based serums are made primarily with water and are especially suited to water-soluble ingredients such as hyaluronic acid, certain peptides and botanical extracts. They generally have a very light texture, absorb quickly and can provide hydration without adding much richness.
Oil serums contain little or no water. Instead, they use plant oils, oil-soluble emollients or squalane as their base. This makes them particularly well suited to oil-soluble antioxidants, lipid-compatible botanical extracts and certain encapsulated ingredients. They also help replenish the lipids that keep skin feeling soft, supple and comfortable.
Neither format is automatically better. The right choice depends on the actives being used, the desired skin benefits and, most importantly, the needs of the skin itself.
Why we formulated ʻIli Nani as an oil serum
Vitamin C is a famously challenging ingredient to formulate with. Pure L-ascorbic acid is highly effective, but in conventional water-based formulations it can oxidize when exposed to water, air, heat and light. This is why some vitamin C serums gradually turn dark yellow, orange or brown after opening.
Water-based L-ascorbic acid serums are also usually formulated at a low pH, often below 3.5, to help the vitamin C remain effective and penetrate the skin. Not every water-based vitamin C derivative requires this acidity, but traditional L-ascorbic acid formulas often do.
For context, the skin’s natural surface pH averages around 4.7. A more acidic vitamin C serum is not inherently harmful, but it may cause stinging or feel uncomfortable on skin that is already dry, sensitive or reactive.
In ʻIli Nani, the vitamin C is encapsulated within cornflower stem cells. This delivery system helps protect and stabilize it while allowing us to create a waterless formula that does not depend on a very low-pH environment. It also increases the bioavailability of the ascorbic acid to the skin.
Because a waterless oil does not have a measurable pH in the same way that a water-based product does, it offers a different approach to delivering vitamin C. It is an approach designed with comfort, stability and sensitive skin in mind.
The oil base also allows us to surround the vitamin C with nourishing tropical seed oils and complementary antioxidants, including licorice root extract, vitamin E and ethyl ferulate.
Vitamin C works beautifully with other antioxidants
Vitamin C, vitamin E and ferulic acid are often described as antioxidant partners. Research on topical formulas containing vitamins C and E with ferulic acid has shown that the combination can improve antioxidant stability and provide stronger protection against oxidative stress than vitamins C and E alone.
ʻIli Nani brings these antioxidant families together in an oil-based format. It contains vitamin E and ethyl ferulate, an oil-compatible derivative of ferulic acid, alongside its stem cell-encapsulated vitamin C.
Rather than relying on one fashionable “hero” ingredient, the formula creates a network of complementary antioxidants. It is further enriched with licorice root, tetrahydrocurcumin, fermented Dragon’s Blood oil and tropical seed oils from passionfruit, pineapple, guava and papaya.
Who may prefer an oil-based serum?
An oil serum can be especially comforting for skin that feels dry, depleted or increasingly reactive. These changes are common during perimenopause and menopause, when hormonal shifts can affect the skin’s moisture levels, suppleness and barrier function.
This does not mean that oil serums are exclusively for mature or dry skin. A finely formulated oil serum can also suit combination skin, particularly when the skin feels dehydrated beneath the surface. ʻIli Nani has a silky, lightweight texture and is designed to absorb without leaving a heavy or greasy residue.
If your skin already produces plenty of oil or you primarily want weightless hydration, a water-based serum may be a better fit. If your skin is craving nourishment, softness and antioxidant care in one step, an oil serum may offer more of what it needs.
What did our testers notice?
In an eight-week in-house consumer study, 20 women tested ʻIli Nani:
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100% said their skin felt more moisturized.
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100% noticed softer-feeling skin.
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70% noticed brighter, more radiant-looking skin.
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65% said their skin appeared more dewy and glowing.
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55% noticed an improvement in uneven-looking skin tone.
These are not vague promises. They are the experiences reported by real women using the finished formula.
Recognized as a leading vitamin C serum
ʻIli Nani was also named a finalist in the Best Vitamin C Serum category at the 2026 Beauty Shortlist Awards.
This independent recognition is especially meaningful to us because it shows that an effective vitamin C serum does not have to come in a watery format. An oil-based serum can still be recognized by beauty experts as an exceptional vitamin C treatment. What matters is the quality of the ingredients, the intelligence of the formulation and how beautifully the product performs on the skin.
How to use an oil serum
After cleansing, apply two to three drops of ʻIli Nani to clean, slightly damp skin and gently massage it over the face and neck.
For the complete Noelani ritual:
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Cleanse with Kuʻuipo.
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Apply two to three drops of ʻIli Nani.
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Layer Hōkūloa Moisturizer on top if your skin needs additional moisture and barrier support.
A few drops truly are enough. ʻIli Nani can be used morning or evening and also provides beautiful slip for a gentle nighttime gua sha ritual.
Oil serum versus water serum is not about one format winning. It is about choosing a formula designed around the ingredients it carries and around what your skin needs now.
Discover ʻIli Nani Vitamin C Oil Serum and experience vitamin C formulated with nourishment, stability and sensitive skin in mind.
