Ultraviolet (UV) radiation remains one of the primary environmental stressors affecting skin health. Daily exposure to UVA and UVB rays contributes to oxidative stress, inflammation, premature skin aging, and long-term cellular damage. While topical sunscreens are the cornerstone of photoprotection, growing scientific interest is now focused on oral photoprotective strategies that provide systemic and continuous support.

 

In this context, Complife conducted two randomized, double-blind, placebo-controlled clinical trials to investigate the effects of oral supplementation with standardized coriander (Coriandrum sativum L.) seed oil (CSO) on UV-induced skin damage.

The results, published in Cosmetics (December 2025), represent the first clinical evidence demonstrating the photoprotective potential of coriander seed oil in humans.

 

Why Oral Photoprotection?

Topical sunscreens act as a physical or chemical barrier against UV radiation. However, their effectiveness depends on correct application and reapplication. Oral photoprotective agents, by contrast, work systemically, helping to:

• Strengthen the skin’s intrinsic defense mechanisms
• Reduce oxidative stress
• Modulate inflammatory responses
• Support overall skin resilience against UV exposure

This inside-out approach does not replace sunscreen but may serve as a complementary strategy to enhance protection.

 

The Active Ingredient: Coriander Seed Oil (CSO)

The tested ingredient is a virgin coriander seed oil obtained by mechanical pressing. It is particularly rich in petroselinic acid, a rare monounsaturated fatty acid known for its anti-inflammatory properties.

In addition to petroselinic acid, coriander seed oil naturally contains:

• Linoleic acid
• Phytosterols
• Tocopherols and tocotrienols

These bioactive compounds are recognized for their role in maintaining epidermal barrier integrity and supporting the skin’s response to environmental stressors.

 

Study Design

Two independent clinical trials were conducted at Complife facilities in Italy:

• Study 1: Women with reactive skin
• Study 2: Women with various skin types

Participants received 200 mg/day of coriander seed oil or placebo for 56 days.

The studies evaluated:

• UV-induced skin erythema
• TNF-α release (a key pro-inflammatory cytokine)
• Lipoperoxidation (marker of oxidative damage)

All measurements were performed before and after supplementation, following controlled UVA or UVA+B exposure.

 

Key Results

Reduction in UV-Induced Erythema

After 56 days of supplementation:

• In women with reactive skin, UV-induced erythema decreased by 11.8% in the CSO group.
• In women of all skin types, erythema decreased by 18.1%.

These reductions were statistically significant compared to placebo.

Modulation of Inflammatory Response

TNF-α levels significantly decreased:

• −24.1% in women with reactive skin
• −18.7% in women of all skin types

This confirms a measurable anti-inflammatory effect following UV exposure.

Reduction in Oxidative Stress

In the all-skin-type cohort, UVA-induced lipoperoxidation was significantly reduced:

• −31.9% at 4 hours post-exposure
• −69.9% at 24 hours post-exposure

These findings highlight a strong antioxidant effect associated with coriander seed oil supplementation.

 

Clinical Relevance

Together, these results suggest that oral coriander seed oil supplementation:

• Enhances skin resilience to UV-induced stress
• Reduces inflammation and oxidative damage
• Supports a systemic inside-out photoprotective strategy

Importantly, the supplementation was well tolerated, with high compliance and no reported adverse events.

 

As UV exposure continues to be a major contributor to skin damage and photoaging, innovative complementary strategies are needed. Oral supplementation with coriander seed oil represents a promising adjunct to conventional sun protection approaches.

By acting at the molecular and cellular levels, this ingredient may help reinforce the skin’s natural defenses against UV-induced inflammation and oxidative stress.

 

Download the complete methodology, statistical analysis, and detailed results in the full article published in Cosmetics (2025).

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