How we test

In brief

Each claim shape has a method behind it, and each method measures one thing. A claim is worded to the endpoint its method measured, and never wider. This page describes the methods. Peer-reviewed studies on the ingredients themselves are summarized in published research on our ingredients.

Instrumental skin measurements

These are level C methods when run by a third-party laboratory on the finished product, in volunteers, under controlled room temperature and humidity after an acclimatization period. A study page states the number of participants, the duration, the control and the statistics.

Skin hydration, by corneometer. A probe measures the electrical capacitance of the outermost layer of skin, which rises with its water content. Readings are taken before application and at set times after. It supports a hydration statement, such as a change at a stated time point.

Moisture loss, by TEWL. Transepidermal water loss is the rate at which water evaporates from the skin surface, measured by a probe that reads the humidity gradient just above it. A lower rate indicates the skin is holding water more effectively. It supports a statement about visible moisture loss and barrier appearance, with the number and time point.

Elasticity, by cutometer. A probe draws the skin into an aperture by gentle suction and releases it, and an optical sensor records how far it moves and how it returns. It supports statements about the look and feel of firmness and elasticity.

Tone and redness, by chromameter. A colorimeter reads skin color in standardized color coordinates, giving values for lightness and for red and yellow. Related probes report melanin and redness indices. It supports statements about the look of tone and visible redness, with the number, site and time point.

Skin compatibility

Repeat insult patch test. The product is applied repeatedly under patches to the same site over several weeks in a panel of volunteers, followed by a rest period and a final challenge patch on fresh skin. A dermatologist or trained grader scores each site. The result states how many participants completed the study and whether any reactions were recorded. It supports a skin compatibility statement worded to that panel.

Microbiological quality

Preservative efficacy. The finished product is inoculated with defined bacteria, a yeast and a mold, and the surviving counts are measured at set intervals over several weeks. The reduction is compared with the acceptance criteria of the method. It shows whether the preservative system protects the formula in use. It is run on a named lot.

Microbial limits. A sample of a released lot is tested for the total count of aerobic bacteria, yeasts and moulds, and for the absence of specified organisms. It shows the microbiological quality of that lot at release.

The standards and pharmacopoeia methods Vegalab uses for both, and the lots tested, are set out on the testing program.

Formulation and stability

These are level B methods, run by Vegalab or its manufacturing partner, with the method stated beside any figure.

Stability. Samples in the final pack are stored at room temperature, at elevated temperature, through freeze and thaw cycles and under light. Appearance, color, odor, pH, viscosity and the pack itself are checked at set intervals. It supports shelf life and storage statements. Elevated temperature shortens the study; real-time storage confirms it.

pH. The finished product is measured with a calibrated meter at a stated temperature. Each formula's pH is recorded from its batch record. It matters most for formulas containing acids.

Particle size. Dynamic light scattering measures how particles in a liquid scatter a laser as they move, and reports an average size and the spread of sizes. Electron microscopy can confirm shape. It supports a statement about capsule size, method stated. How the capsules are built is explained on particle size.

Consumer perception

A questionnaire completed by participants after a set period of use. It records what people report, not what an instrument measured. Every percentage from one is published with the number of participants, the duration, the question as asked, and this qualifier: self-assessed, consumer perception, not an instrumental measurement.

What every study page states

Formula and lot. Laboratory. Sponsor. Design and sample size. Comparator or control. Conditions. Endpoints and statistics. Results. Limitations. The claims the study is cleared to support. A study page with no stated limitation does not publish.

The grading behind these methods is set out on evidence levels, A to D. The evidence hub indexes every claim by formula, and the science and claims charter sets the rules for how a result becomes a claim. For documents on a specific formula, professional accounts can use professional documentation.