PDRN.AI product reviews follow a documented testing methodology. This page describes that process — what we do, how long we do it, and what we measure.
Test design
- One tester per product (baseline reviews): the same person uses the product across the full test period to control for skin type, climate, and routine variables
- Multiple testers (comparison reviews): when ranking multiple products, we recruit 3-5 testers with different skin profiles
- Controlled baseline routine: all testers maintain the same cleanser, moisturizer, and SPF during the test period — only the reviewed product changes
- Half-face protocol where applicable: for serums and treatments, the product is applied to one side of the face only, with the other side serving as control
Test duration
- Cleansers and toners: 4 weeks
- Moisturizers and hydrators: 4 weeks
- Active serums (vitamin C, niacinamide): 6 weeks
- Retinoids: 12 weeks minimum
- PDRN and regenerative ingredients: 8-12 weeks (the mechanism is slow; shorter tests miss the effect)
- Sunscreens: 2 weeks plus a stress test (high-UV exposure day with documented application)
What we document
- Baseline photographs: consistent lighting, no makeup, taken at the same time of day
- Weekly photos at the same conditions
- Symptom log: stinging, dryness, breakouts, flushing, perceived effect
- Texture measurements: where relevant (texture-focused products like exfoliants)
- Routine compatibility: what other products it played well with, what caused conflicts
What we don’t do
- Clinical instrumentation — we don’t have corneometers, sebumeters, or VISIA imaging. Our reviews are observational, not clinical.
- Long-term efficacy claims beyond test period — we don’t claim a product will deliver six-month results from a six-week test
- Comparisons across skin types we don’t have testers for — if all our testers have normal-combination skin, we note that limitation when relevant
Conflicts of interest
Most products we review are purchased at retail. Some are sent as press samples — when they are, we note it. Receiving a sample does not guarantee a positive review.
Where evidence is limited
For ingredients with thin clinical evidence (new molecules, novel delivery systems), we say so explicitly. Absence of evidence isn’t evidence of absence — but it’s also not a free pass to claim efficacy.
Questions
Methodology questions or suggestions: hello@pdrn.ai