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The Science
Beyond PDRN. A complete overnight system.
Many brands now sell PDRN on its own. Cotrini pairs S‑DNA™ with calming Korean botanicals and allantoin, so the whole formula works on your skin barrier, and proves it in independent clinical testing.
- +52%skin hydration in 4 weeks*
- 19%firmer skin, measured*
- 0.05irritation index: non-irritating*
What is PDRN?
DNA, from salmon, for your skin.
PDRN (polydeoxyribonucleotide) is a mix of purified DNA fragments from salmon, one of the most talked-about actives in Korean dermatology.
S‑DNA™ is Cotrini’s PDRN. It comes from salmon harvested for food, so none of the fish goes to waste. On the label it appears as sodium DNA (polydeoxyribonucleotide).
The formula
Salmon DNA, with Korea’s calming botanicals.
Every ingredient has a job: hydrate, comfort, and protect the look of your skin barrier. Fragrance-free.
S‑DNA™ salmon PDRN
Purified DNA fragments from salmon, one of Korean dermatology’s most researched actives, for the look of renewed, resilient skin.
Reishi and Phellinus linteus
Two prized Korean mushrooms that help calm the look of stressed, tired skin.
Centella asiatica
A staple of Korean skincare that soothes and comforts dry, tight-feeling skin.
Ginseng and Scutellaria
Antioxidant-rich botanicals for a brighter, more even-looking complexion.
Shea butter, trehalose and betaine
Hold in moisture so skin feels soft and cushioned by morning.
Allantoin
Softens and soothes. And the formula is fragrance-free.
Full ingredient list
Aqua, PEG-8, Glycerin, PEG-90, Butyrospermum Parkii (Shea) Butter Extract, Ganoderma Lucidum Fruiting Body (Mushroom) Extract, Cnidium Officinale Rhizome Extract, Caprylyl Glycol, Cetearyl Alcohol, Glyceryl Stearate, PEG-100 Stearate, Polysorbate 60, Sorbitan Stearate, C13-14 Isoparaffin, Laureth-7, sodium DNA (polydeoxyribonucleotide), Betaine, Trehalose, Allantoin, Centella Asiatica Extract, Phellinus Linteus (Mushroom) Extract, Perilla Frutescens Leaf Extract, Scutellaria baicalensis root extract, Panax Ginseng Extract, Pueraria Lobata Root Extract, 1,2-Hexanediol, Butylene Glycol, Phenoxyethanol, Disodium EDTA (ethylenediaminetetraacetic acid).
The clinical studies
Four studies. One night cream.
Independent testing of the Night Cream: measured by instrument, graded by a dermatologist, and rated by the women who used it.
Study 01 · Efficacy
Hydration, firmness, elasticity and tone
- Who
- 34 women aged 30–55
- How long
- 4 weeks, measured at 2 and 4 weeks
- Design
- Split-face: the cream on one side, the other side untreated
- Measured by
- Corneometer®, Cutometer® and Mexameter®; fine lines graded by a dermatologist
- Lab
- Delivery Clinical Studies S.A.S., 2023
| Result | 2 weeks | 4 weeks |
|---|---|---|
| Skin hydration | +34%every participant improved | +52%every participant improved |
| Skin elasticity | +18% | +23% |
| Firmer skin | — | 19% |
| Brighter-looking skinless visible pigment | 82%of women improved | 91%of women improved |
| Visibly reduced fine linesdermatologist-graded | — | 44%of women, vs. 3% on the untreated side |
Study 02 · Perception
What women said
- Who
- 32 women from the efficacy study
- How long
- 4 weeks
- Method
- Self-assessment questionnaire
| After 4 weeks | Agree |
|---|---|
| Skin feels firmer | 100% |
| Skin feels softer | 100% |
| Would use it again | 97% |
| Rated it good or very good for skin’s appearance | 97% |
| Expression lines and wrinkles look reduced | 91% |
| Skin tone and spots look improved | 84% |
Study 03 · Barrier
Recovery of irritated skin
- Who
- 54 participants
- How long
- 14 days
- Design
- Skin irritated under lab conditions, then treated with the cream or left untreated
- Measured
- Hydration and moisture loss
| Day | Treated vs. untreated |
|---|---|
| Day 2 | A statistically significant improvement in hydration and moisture barrier, vs. untreated skin |
| Day 5 | 69%less moisture loss, vs. 58% untreated |
| Day 12 | Back to its healthy hydration level. Untreated skin was still 22% below |
| Day 14 | 13.5%more hydrated than before the irritation. Untreated skin was still 12% below |
Study 04 · Safety
Dermatologist patch test
- Who
- 22 participants
- How long
- 48-hour patch, checked again at 72 hours
- Supervised by
- A dermatologist
| Result | |
|---|---|
| Irritation index | 0.05classified non-irritating |
| Participants with clear skin at 72 hours | 22 of 22 |
*Efficacy study: Delivery Clinical Studies S.A.S. (2023), average change from baseline, each significant vs. the untreated side; firmness significant at 4 weeks. Brighter-looking skin measured as less visible pigment (Mexameter®). Anti-irritation study: non-serious mild irritation induced under lab conditions. Individual results vary.
Real results
See the difference
44%of women showed visibly reduced wrinkles after 4 weeks, graded by a dermatologist, vs. 3% on the untreated side of the face.*
Before
After
Before
After
Before
After
Before
After*Independent 4-week split-face study, Delivery Clinical Studies S.A.S. (2023): 34 women aged 30–55; dermatologist evaluation of wrinkle reduction. Individual results vary.
Shop the Night CreamSee it for yourself
Try 14 nights for $35
Hydration rose 34% in just 2 weeks in our clinical study.* Your $35 is credited toward your first full jar.
Free shipping & samples
Free U.S. shipping and complimentary samples with every order.
30 nights to fall in love
Not for you? Return the jar, even empty, for a full product refund.
Auto-replenish & save 20%
A new jar every 3 months, timed to your last one. Skip or cancel anytime.