| QUICK ANSWER PDRN’s evidence base in topical skincare rests on two study types: ex vivo Franz diffusion testing (OECD TG 428), which confirms whether the ingredient crosses the skin barrier, and HDF cell-based studies (ISO 10993-5), which measure biological activity at the cellular level. Understanding both — and what they can and cannot tell us — is the only rational basis for evaluating PDRN product claims. |
Why the PDRN evidence base matters
PDRN is experiencing rapid growth in the Indian skincare market, driven largely by its clinical pedigree in injectable aesthetic medicine. The risk inherent in this transition is familiar: an ingredient with genuine injectable evidence becomes a marketing term applied to topical formulations with no formulation-level data to support the claims.
The result is a market where dozens of products carry ‘PDRN’ on the label, few can cite the concentration used, fewer still can produce delivery or permeation data, and none — until recently — had published formulation-level testing specific to the Indian skincare context.
For editors, dermatologists, and informed consumers, this guide provides the framework to distinguish evidence-backed PDRN from label decoration.
The two types of PDRN studies you should know about
In vivo injection trials
The majority of published PDRN clinical evidence comes from injectable protocols — administered intradermally or subcutaneously by trained practitioners. These studies demonstrate strong evidence for wound healing, skin rejuvenation, and collagen stimulation, but they are not directly applicable to topical formulations. Injected PDRN bypasses the skin barrier entirely, achieving dermal concentrations that no topical product can replicate through surface application alone.
Citing injectable PDRN evidence to support topical product claims is a common and significant misrepresentation in brand marketing.
Topical ex vivo studies
The relevant evidence for topical PDRN comes from two methodologies: Franz diffusion permeation studies, which assess whether and how quickly the ingredient crosses excised human or animal skin under controlled conditions, and HDF (human dermal fibroblast) cell-based studies, which assess biological activity — collagen stimulation, melanin inhibition, cell proliferation — in response to the formulation.
Both are necessary. Permeation data without biological activity data tells you the ingredient gets in but not what it does. Biological activity data without permeation data tells you it is active in cell culture but offers no evidence it reaches skin cells in vivo.
What Franz diffusion testing tells us
Franz diffusion is an ex vivo skin permeation method conducted using a diffusion cell apparatus — the Franz cell — in which excised skin (human cadaver skin or validated synthetic membrane, per OECD TG 428) is mounted between a donor compartment containing the test formulation and a receptor compartment containing a receptor fluid. At defined time intervals, the receptor fluid is sampled and analysed for the presence of the test substance.
The critical outputs are: cumulative permeation (how much crosses over time), flux (the rate of permeation at steady state), and lag time (the time before steady-state flux is established). Lag time is particularly informative for practical use: a shorter lag time means the ingredient begins meaningful skin penetration sooner after application.
What Boldpurity’s PDRN permeation data shows
Franz diffusion testing was conducted on the SkinReset™ PDRN Serum formulation by ACME Research Solutions, Meerut, under OECD Test Guideline 428. The study confirmed PDRN permeation with a lag time of approximately 23 minutes — meaning measurable PDRN transfer across the excised skin membrane begins within 23 minutes of application under ex vivo conditions.
† This result reflects ex vivo conditions using excised human skin membrane. Ex vivo data is widely used as the primary regulatory and research standard for topical permeation assessment but does not predict in vivo outcomes with absolute precision.
Why lag time matters for real-world results
A lag time of 23 minutes means that meaningful dermal delivery begins during a standard skincare application period — not hours after application when the product has dried and its concentration gradient has dissipated. In practical terms, the 30–60 second press-in application recommended for PDRN serums is mechanistically justified by this data: it allows the initial permeation process to establish before the product is sealed with a moisturiser.
The collagen stimulation evidence
+41–43% collagen stimulation: what the HDF cell data shows
An HDF (human dermal fibroblast) cell-based collagen stimulation study was conducted by Invitra, India, under ISO 10993-5 standards. The SkinReset™ PDRN Serum formulation demonstrated a 41–43% increase in collagen production in treated fibroblast cells compared to untreated controls over the study period.
ISO 10993-5 is a cytotoxicity standard — its primary purpose is to confirm that a material does not harm cells. Using it as the framework for a collagen stimulation study is methodologically significant: it confirms both that the formulation is non-cytotoxic at the tested concentration and that it demonstrably upregulates collagen production in treated cells.
† In vitro HDF cell-based study. Results reflect measurable upregulation of collagen protein production in treated fibroblast cells vs untreated control. In vitro results do not guarantee identical in vivo outcomes.
How this compares to retinol and peptide benchmarks
Published retinol in vitro data typically shows collagen stimulation in the range of 30–80% depending on concentration, study design, and cell line. Peptide complexes (Matrixyl, Argireline) typically show 20–50% in cell-based assays. The +41–43% recorded for the SkinReset™ formulation is within the upper range of peptide data and comparable to low-to-mid concentration retinol — without retinol’s cytotoxicity profile.
The melanin reduction data
46.1% melanin reduction and 27.8% tyrosinase inhibition
The same ex vivo study protocol recorded a 46.1% reduction in melanin content in treated tissue samples versus untreated controls, alongside 27.8% tyrosinase inhibition — approximately twice the tyrosinase inhibitory activity of niacinamide at standard cosmetic use concentrations (typically 5%).
What tyrosinase inhibition means for the appearance of skin tone
Tyrosinase is the rate-limiting enzyme in melanin biosynthesis. It catalyses the conversion of tyrosine to DOPA and DOPA to dopaquinone — the early steps in the melanin production cascade. Inhibiting tyrosinase reduces melanin synthesis at the source, rather than attempting to accelerate its removal through exfoliation or bleaching agents.
For Indian skin, where post-inflammatory hyperpigmentation is driven by upregulated tyrosinase activity in response to UV exposure or inflammatory stimulus, a ~28% inhibitory effect represents a meaningful functional advantage — particularly when combined with PDRN’s anti-inflammatory A2A receptor activity that reduces the inflammatory trigger for PIH in the first place.
The ~2× niacinamide advantage
Niacinamide is currently the most widely used skin tone–evening ingredient in Indian skincare. Its mechanism is different from tyrosinase inhibition — niacinamide primarily inhibits the transfer of melanin from melanocytes to keratinocytes rather than melanin synthesis itself. The comparison is therefore not direct, but as a market benchmark, a 27.8% tyrosinase inhibition figure represents a more upstream and complementary mechanism.
What the evidence does not tell us yet
Intellectual honesty requires acknowledging the limitations. Franz diffusion data and HDF cell studies are ex vivo and in vitro methodologies — they are conducted outside the living human body and cannot fully replicate the complexity of real skin biology, blood flow, immune response, and individual variation. Large-scale randomised controlled trials (RCTs) on topical PDRN in Indian skin populations do not yet exist.
What the available evidence does establish: the formulation crosses the skin barrier within a relevant timeframe, it is non-cytotoxic at the use concentration, and it demonstrably stimulates collagen production and inhibits tyrosinase activity in cell-based conditions. That is a stronger evidence platform than the vast majority of skincare actives available in the Indian market.
How to evaluate PDRN products using this framework
When assessing any PDRN product, apply these four questions:
- Does the brand publish permeation data (Franz diffusion, OECD TG 428) for the finished formulation — not just for the raw material?
- Does the brand publish cytotoxicity clearance (ISO 10993-5) confirming the formulation is safe at the concentration used?
- Is the PDRN concentration disclosed? (Look for 2,000–5,000 PPM Sodium DNA as a minimum benchmark for premium formulations.)
- Is the data formulation-specific? Raw material supplier data tested at laboratory concentrations does not predict the performance of a finished serum.
To the best of available knowledge, SkinReset™ PDRN Serum by Boldpurity® is the only Indian D2C skincare brand that has published ex vivo permeation data (OECD TG 428) alongside ISO 10993-5 cytotoxicity clearance and HDF collagen stimulation data for a finished serum formulation in a consumer-accessible format.
For further information on Boldpurity’s formulation philosophy and science methodology, visit boldpurity.com.
Scientific references
1. Thellung S. et al. (1999). Polydeoxyribonucleotides promote proliferation of human skin fibroblasts. Journal of Cellular Physiology. PubMed ↗
2. Bitto A. et al. (2011). PDRN reduces TGF-β1 via A2A receptor activation. Journal of Vascular Surgery. PubMed ↗
3. OECD Test Guideline 428: Skin Absorption — In Vitro Method. OECD.org ↗
4. ISO 10993-5:2009 — Biological evaluation of medical devices: Tests for in vitro cytotoxicity. ISO.org ↗
5. Boldpurity® Internal Study Data (2025). PDRN ex vivo skin permeation (OECD TG 428) and HDF collagen stimulation (ISO 10993-5). Invitra & ACME Research Solutions, India.
About the author
Khatija is an Internationally certified cosmetic scientist with IFSCC-affiliated training from Australia and co-founder of Boldpurity®, a cGMP-certified luxury clinical skincare brand based in Hyderabad, India. For media enquiries: care@boldpurity.com
This article is submitted for editorial consideration and is the original work of the named author. All clinical data cited refers to in vitro or ex vivo studies. Content does not constitute medical advice.
