Silybum Marianum Ethyl Ester
INCI: SILYBUM MARIANUM ETHYL ESTER
Reviewed by Daisy · Last updated 2 Jun 2026
A plant-derived ester that conditions and supports skin resilience
Best For Skin Types
All, Dry, Sensitive, Mature
Addresses
Usage Frequency
Daily
What Is Silybum Marianum Ethyl Ester?
Silybum marianum ethyl ester is a derivative of milk thistle seed extract, where the plant's bioactive compounds have been chemically modified into an ester form. This modification is designed to improve stability and absorption when used in skincare formulations.
As a skin conditioning agent, it works to soften and smooth the skin surface whilst helping to maintain hydration levels. The ingredient is included in formulations to support overall skin comfort and appearance.
How It Works
Milk thistle contains silymarin, a complex of flavonolignans known for their antioxidant and anti-inflammatory properties. By converting these compounds into an ethyl ester, the ingredient becomes more stable in formulation and potentially more capable of penetrating the outer layers of skin.
Once applied, the ester is believed to deposit a conditioning film on the skin surface whilst its antioxidant compounds may help neutralise free radicals that contribute to oxidative stress and skin ageing.
Clinical Evidence & References
Research on milk thistle derivatives in skincare is ongoing, though the plant itself has a long history of traditional use. Studies suggest silymarin possesses antioxidant and anti-inflammatory properties, though evidence specifically for the ethyl ester form in cosmetic applications remains limited.
Most evidence supporting this ingredient comes from botanical research and in-vitro studies rather than large-scale human clinical trials. It is generally considered a supportive ingredient rather than a targeted treatment for specific skin concerns.
How to Use
Silybum marianum ethyl ester is typically found in leave-on products such as serums, moisturisers and treatment creams. It works well in combination with other conditioning and antioxidant ingredients. Apply to clean skin as directed by your product's instructions, adjusting frequency based on how your skin responds.
Safety & Precautions
Frequently Asked Questions
From the Clinic
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