Sunscreen Filters

Methoxycinnamic Acid

INCI: METHOXYCINNAMIC ACID

Reviewed by Emma · Last updated 14 Aug 2026

A cinnamic acid derivative that offers UV protection and helps stabilise formulations

Best For Skin Types

All

Addresses

Sun damage, Premature ageing, UV exposure

Usage Frequency

Daily

What Is Methoxycinnamic Acid?

Methoxycinnamic acid is a naturally-derived compound belonging to the cinnamic acid family, a group of plant-based phenolic compounds. It functions primarily as a UV filter, absorbing ultraviolet radiation to help protect skin from sun damage. In formulations, it also serves a stabilising role, helping to maintain product integrity over time.

This ingredient has been studied as an alternative to some conventional synthetic UV filters, with research exploring how different delivery systems can optimise its absorption into the skin.

How It Works

Methoxycinnamic acid absorbs UV radiation by converting it into heat, which is then dissipated from the skin. This mechanism helps reduce the penetration of harmful UV rays that can cause photodamage, premature ageing, and other sun-related skin concerns.

As a stabilising agent, it helps prevent degradation of other ingredients in the formula, extending the product's useful lifespan and maintaining its intended benefits.

Clinical Evidence & References

Research suggests that methoxycinnamic acid and its derivatives have measurable UV-absorbing capacity comparable to established UV filters. Studies using in vitro sun protection factor measurements have demonstrated protective potential when incorporated into formulations, particularly when paired with carrier systems that optimise skin delivery.

However, evidence on real-world efficacy in sunscreen products and long-term skin benefits in humans remains limited. Most available data comes from laboratory and animal studies rather than clinical trials in human subjects, so broader safety and efficacy claims require further investigation.

How to Use

This ingredient is typically used within finished sunscreen and protective skincare formulations rather than as a standalone product. Follow the application instructions on your specific product; for sun protection, ensure adequate coverage and reapplication as directed. It works best as part of a comprehensive sun protection routine that includes broader UV defence strategies.

Safety & Precautions

Methoxycinnamic acid is generally well-tolerated in skincare formulations. As with any sun protection ingredient, patch testing is sensible if you have sensitive skin or known allergies to cinnamic acid derivatives.

Frequently Asked Questions

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