Antioxidant Activity Test



The OxiSelect™ method predicts the antioxidant potential of ingredients or formulations against all major types of Reactive Oxygen Species (ROS), using human epidermal keratinocyte cultures as an in vitro system with a high level of physiological relevance for human skin. The test can be used to provide supporting data for a number of claims including antioxidant, anti-ageing, anti-pollution and anti-inflammatory.


Oxygen is an essential requirement for life, but it is also a very reactive molecule and can be harmful when converted to reactive oxygen species (ROS) within the body. ROS are unstable and react with most biological molecules, causing damage to vital cellular components such as DNA, proteins and lipids, contributing to inflammation and ageing. Stress and exposure to air pollutants can dramatically increase ROS levels in the skin and lead to an acceleration of the inflammatory and ageing pathways. Our cells are equipped with natural antioxidant enzymes to prevent ROS from forming, or to remove them before they cause damage. Providing our skin with an antioxidant boost through active ingredients in cosmetic products can help to enhance the skin’s own natural protective mechanisms. Antioxidant ingredients may therefore support a variety of claims including anti-pollution and anti-ageing.

The OxiSelect™ test method exposes human skin cells (epidermal keratinocytes) to a range of concentrations of the active ingredient(s), either alone or in combination. Unlike antioxidant tests that utilise simple biochemical reactions in a test tube, the use of whole cells provides a more complete environment with higher physiological relevance, accounting for important aspects such as pH, cellular uptake and metabolism, as well as demonstrating the efficacy of the test item. OxiSelect™ captures anti-oxidant contributions from all major types of ROS, including peroxides, superoxides, hydroxyl radicals and singlet oxygen.

The test is based on the intracellular conversion of DCFH to its fluorescentmetabolite (DCF). The reaction is inhibited by antioxidants, reducing the amount of fluorescence observed. OxiSelect™ is suitable for ingredients or formulations with sufficient aqueous solubility in cell culture medium.


A OxiSelect™ uses human skin cells (epidermal keratinocytes) in animal product-free culture, providing a physiologically relevant environment. Cells are obtained from a commercial source with full donor consent and QC screening.

B The method uses a specialised marker called DCFH-DA, which diffuses into cells and is metabolised by cellular esterases. The metabolite (DCFH) is rapidly oxidised to highly fluorescent 2’,7’-DCF by reactive oxygen species (ROS) in the presence of the proprietary “Free Radical Initiator”. The fluorescence intensity is proportional to the levels of ROS within the cell, and is therefore reduced in the presence of antioxidant active ingredients. The plant flavonoid, quercetin, is used as a positive control.


  • Preliminary steps establish the solubility of the active ingredient or product and a cytotoxicity screen determines the highest concentration that the cells will tolerate without causing cell damage.
  • Human epidermal keratinocytes are cultured until 80-90% confluent in 96-well plates, in animal product-free culture conditions.
  • DCFH-DA probe solution is added to the cells along with Quercetin (positive control), or the active ingredient(s) or product, at the specified concentrations.
  • After incubation for 60 minutes at 37°C, cells are rinsed and Free Radical Initiator solution is added to the wells.
  • Fluorescence intensity (to quantify DCF) is read immediately and monitored over a 60-minute period, in increments of 5 minutes.
  • Results for each of the test conditions are plotted in graph format, to demonstrate any dose-dependent antioxidant potential of the active ingredients or product, either alone or in combination.

Get in touch today to ask for pricing information.


One of our clients wanted help to determine the antioxidant potential of five different active ingredients for a new anti-ageing skincare formulation. Read the case study to discover how our in vitro test allowed the active ingredients to be ranked based on different concentrations and combinations.

Antioxidant test

At a glance

What it measuresFree radical levels
Turnaround time4-8 weeks
Sample required10ml (liquids) / 10g (solids)
Test codeCT-023

Always animal and animal product-free


Request A Quote

Test Required

Quantity of Test item

This form collects your data so that we can respond to your enquiry.

I consent to XCellR8 handling my data.

Please see our privacy policy for more information on how we protect and manage your data.

We’d like to send you occasional news from XCellR8 via email such as new product launches, regulatory updates and useful guides. We will never sell your data to anyone else and you can unsubscribe at any time.

Yes, I’d like to hear about news and services

No, I don’t want to hear about news and services

Enter the Captcha