PDRN Serum Before and After: A 4-Week Photo and Reaction Log

Point	Detail	Source
Human studies of applied products	The evidence we reviewed has no human study that tested PDRN in a cosmetic ampoule or cream on its own	Editorial evidence review
Closest human data	A preliminary study (2004) used a medical PDRN ointment on skin graft donor sites in 40 patients, not a cosmetic	2004 PMID 15025849 · B
Data mixed with procedures	A study of 100 people with acne scars added a multi-ingredient topical serum to a laser procedure	2026 PMID 42621380 · A
Photo records	Agreement between photo-based and in-person assessment varied with photo quality and assessor experience (16 studies, 927 people)	2025 PMID 41178312 · A
Teens	Of 248 teens, 26.5% had a side effect from cosmetics, and 18.0% had tested beforehand	2026 PMID 42493743 · B

What should you expect over 4 weeks, and what shouldn’t you?

What you can reasonably expect to learn is how it feels, whether it irritates, and whether it fits into your daily routine; expecting changes in marks, scars, or firmness doesn’t match the evidence. That is because the evidence we reviewed has no human study that tested an applied PDRN cosmetic on its own.

All of the human data come from medical settings. The 2004 preliminary study used a medical PDRN ointment on the wounds of 40 skin graft donor site patients (20 in each group) and looked at how long the wounds took to close, which is a different condition from putting a cosmetic on your face. The 2026 study of 100 people with acne scars combined a laser procedure with a multi-ingredient topical serum applied afterward, so PDRN’s share can’t be separated out, and the 1997 study was a lab experiment on cultured fibroblasts. None of the three carries over to what to expect from 4 weeks of an ampoule on your face.

How should you take photos so they can be compared?

On the day before you start and in week 4, take three photos without makeup, front and both sides, at the same window, at the same time of day, and from the same distance. In a 2025 meta-analysis of 16 studies (927 people) comparing skin assessments from photos with in-person assessments, agreement varied with photo quality and assessor experience, and the researchers pointed out that photo-taking was not standardized enough.

A change in lighting alone can make redness and texture look different. If you put a first photo taken under bathroom lights after work next to a week-4 photo taken at a window on a weekend afternoon, you end up comparing the light, not the ampoule. Turn off your phone camera’s beauty or enhancement features, and mark a spot on the floor so you stand in the same place every time.

Can teenagers use PDRN skincare?

There is no PDRN study that looked at teens specifically, so if a teen uses it, follow teen cosmetic safety basics first. The Korea Disease Control and Prevention Agency (KDCA), Korea’s national public health agency, considers cosmetics high in fragrance, preservatives, colorants, and oils potentially harmful to teen skin, and advises testing new products below the ear or on the inner arm first.

In practice, that test is rarely done. In a 2026 survey of 248 teens aged 12 to 18, 26.5% had a cosmetic-related side effect, but only 18.0% had done an allergy test before use. During weeks with more sweat and friction, like exam season or a heavy stretch of gym classes and sports practice, don’t start a new ampoule, and add only one product at a time to your log.

Can you mix pure PDRN into your toner or cream?

The evidence has no study that looked at mixing, and for your log, not mixing is better anyway. Mixing two products creates a combination neither originally had, so if stinging or breakouts appear during the 4 weeks, you can’t separate the cause.

For the same reason, don’t change other products during the 4 weeks. If you bring in even one new cleanser, sunscreen, or makeup item, your photos and log will show the results of two products blended together. If you want to use a concentrate and a cream together, apply the concentrate first and the cream afterward, separately, and write each one in your log.

What kinds of skincare products contain PDRN?

It is used in many formats, such as ampoules, serums, creams, sheet masks, and sunscreens, but no human study has compared results between formats side by side. In Korea, the functional cosmetics category described by the Korean Dermatological Association, a Korean medical society, is limited to three areas related to pigmentation, wrinkles, and UV, and PDRN does not appear in that guidance.

So read “contains PDRN” only as a fact about the formula, and choose the format based on your skin. For example, pick a thin ampoule in shiny summer weather and a cream in winter when indoor heating leaves you tight, and if you log the season and area too, your next choice gets easier.

4-week PDRN ampoule log

Week	Photos	What to write every evening	What not to change	Call for this week
Day before starting	3 photos, front and sides (same window, time, distance)	Current product list, how PDRN is listed in the ingredients	—	Set up the log
Week 1	—	Reaction below the ear or on the inner arm, then stinging 0–3 on one area	Cleanser, sunscreen	If nothing happens, move to the whole face
Week 2	—	Stinging and redness scores, number of new breakouts	Cleanser, sunscreen, makeup	Stop if 2 or higher for three days
Week 3	—	Same items, mark period, late-work, and workout days	Same	Stop if scores go up
Week 4	3 photos under the same conditions as the day before starting	4-week score total, one line on how it felt	Same	Decide whether to keep using it

Base your 4-week call on “was it comfortable to use every day?” rather than “does it look better?” If the difference in photos is unclear, write down that it is unclear, and decide whether to use it another 4 weeks based on cost and how it feels.

When does it make sense to see a dermatologist?

• If redness, itching, or swelling after applying it continues for more than a few days even after you stop, consider seeing a dermatologist.
• If you are allergic to certain source materials such as salmon, ask a doctor before using a product whose origin is unclear.
• If acne scars or indented marks are your concern, check your options with a dermatologist before relying on a cosmetic log.
• If you just had a procedure, check with the clinic that did it before adding a new ampoule.

What the sources tell us, in three points

• A 2025 meta-analysis comparing photo-based and in-person assessment (16 studies, 927 people, PMID 41178312) found that agreement depends on photo quality and assessor experience.
• In a 2026 survey of 248 teens aged 12 to 18 (PMID 42493743), 26.5% had a side effect from cosmetics, and 18.0% had done an allergy test beforehand.
• The human data on PDRN are either medical care, like the preliminary study of an ointment in 40 skin graft donor site patients (2004, PMID 15025849), or combined with a laser procedure (2026, 100 people), so they don’t carry over to what to expect from a cosmetic ampoule.