Direct answer: Ferulic acid is a plant-derived antioxidant used to complement vitamin C and vitamin E in topical formulas. A landmark study found that 0.5% ferulic acid improved the stability and photoprotective effect of a specific solution containing 15% L-ascorbic acid and 1% vitamin E. That result cannot be copied automatically onto every vitamin C derivative or concentration.
Written by the Evolved Health Editorial Team · Published 3 September 2026 · Editorially reviewed; not medically reviewed.
The famous study in one table
| Detail | What was actually tested |
|---|---|
| Vitamin C form | 15% L-ascorbic acid |
| Vitamin E | 1% alpha-tocopherol |
| Ferulic acid | 0.5% |
| Main findings | Improved chemical stability of vitamins C and E and increased measured protection against solar-simulated irradiation |
| What it does not prove | Identical effects for ascorbyl glucoside, another base, another pH or another ferulic-acid percentage |
This distinction matters because “vitamin C + ferulic acid” describes a family of formulas, not one standard recipe.
What ferulic acid is
Ferulic acid is a phenolic antioxidant found in plant cell walls, including grains, fruits and vegetables. In skincare, it is valued for its ability to help neutralise reactive molecules and for its formulation relationship with other antioxidants.
An antioxidant does not become sunscreen. It may complement a morning routine, but it does not provide an SPF or replace broad-spectrum UV protection.
Why vitamin C form changes the answer
L-ascorbic acid is the active form of vitamin C and is difficult to stabilise in water. Ascorbyl glucoside is a derivative that requires conversion and is chosen for a different formulation profile. Their percentages and evidence cannot be compared directly.
Therefore:
- evidence for 15% L-ascorbic acid is not evidence for 15% of a derivative;
- stabilising L-ascorbic acid does not prove the same mechanism is needed for every derivative;
- adding more ferulic acid does not guarantee more benefit;
- the whole formula, packaging and pH remain important.
Is the combination synergistic?
For the exact 15% L-ascorbic acid, 1% vitamin E and 0.5% ferulic-acid solution, the published findings support a meaningful interaction. For a different derivative-based product, “complementary antioxidant support” is the more responsible description unless the finished formula has been tested directly.
This is not pedantry. It protects the customer from assuming that a familiar trio on the front label guarantees the same stability, penetration, tolerance or result as the research formula.
What can you realistically expect?
A well-formulated antioxidant serum may support:
- a brighter, more radiant appearance;
- more even-looking tone over consistent use;
- protection from oxidative environmental stress as part of a broader routine;
- comfortable hydration when humectants and emollients are included.
It should not be promised to:
- replace sunscreen;
- bleach skin;
- remove scars or melasma;
- prevent all sun damage;
- reproduce a study conducted on a different formula.
How to use an antioxidant serum in the morning
- Cleanse or rinse according to your skin’s needs.
- Apply the serum according to its label.
- Add moisturiser if needed.
- Finish with broad-spectrum sunscreen.
- Store the serum as directed and monitor unexpected changes in colour, smell or texture.
If layering causes pilling, reduce optional layer amounts and press rather than repeatedly rubbing. Do not reduce the necessary sunscreen amount.
For the form comparison, read Ascorbyl Glucoside vs L-Ascorbic Acid. If colour changes, use our vitamin C oxidation and orange-serum guide. For realistic tone-change expectations, see the Vitamin C dark-spot timeline.
Where LÉVOJU Vitamin C Serum fits
LÉVOJU Vitamin C Serum contains 2% ascorbyl glucoside and 1% ferulic acid, plus vitamin E, 1% sea-buckthorn oil, botanical oils, hyaluronic acid and Sodium PCA. It is a derivative-based brightening and antioxidant formula for dull, dehydrated and uneven-looking skin. We do not claim that it reproduces the exact C+E+ferulic research formula.
Frequently asked questions
Does ferulic acid make every vitamin C serum stable?
No. Stability depends on the vitamin C form, pH, solvent, packaging, manufacturing and storage as well as supporting antioxidants.
Is 1% ferulic acid better than 0.5%?
You cannot rank formulas from percentage alone. The best-known study used 0.5% in a specific combination; a higher number is not automatic proof of greater performance.
Can vitamin C and ferulic acid replace SPF?
No. They are not sunscreen. Use broad-spectrum sunscreen as the final morning skincare step.
Sources
- PubMed: Ferulic acid stabilises a specific solution of vitamins C and E
- PubMed: C+E+ferulic formula and UV-exposure study
- PubMed: Review of topical vitamin C and derivatives
- PubMed: Topical vitamin C mechanisms and clinical applications
Educational information only. Evidence from one antioxidant formula should not be transferred automatically to another.