PDRN for Acne Scars: Clinical Protocol and Evidence

Acne scarring is one of the most emotionally significant skin concerns that patients bring to aesthetic consultations. Studies consistently show that acne scars — even mild to moderate ones — have a disproportionate impact on psychological wellbeing, self-confidence, and quality of life relative to their objective severity. Patients who have lived with acne scarring for years often arrive at consultation having accepted that 'this is just how my skin is' — and the knowledge that effective treatments exist is genuinely life-changing for many of them.

PDRN (polydeoxyribonucleotide) represents one of the most evidence-supported injectable approaches to acne scar improvement available to aesthetic practitioners. Its mechanism — direct fibroblast proliferation via adenosine A2A receptor activation, collagen synthesis upregulation, and the provision of nucleotide building blocks through the salvage pathway — addresses the fundamental pathology of atrophic acne scars: dermal collagen deficit in the scar architecture.

This guide covers the clinical framework for PDRN in acne scar treatment: scar classification (which types respond to PDRN and which do not), the mechanism of action in scar tissue specifically, the clinical evidence, injection protocol, and the combination strategies — particularly with microneedling and fractional laser — that produce the best outcomes. For the complete PDRN clinical background, see the Complete Practitioners Guide to Polynucleotides and PDRN.

Acne Scar Classification: Which Types Respond to PDRN?

Accurate scar classification is the foundation of appropriate treatment planning — because PDRN's mechanism (collagen induction and fibroblast proliferation) is relevant to some scar types and completely irrelevant to others. Not all acne scars are atrophic, and not all atrophic scars respond equally to PDRN treatment.

Atrophic Scars — The Primary PDRN Indication

Atrophic scars represent tissue deficit — areas where inflammation destroyed collagen and the repair process was insufficient to restore the original dermal architecture. Three morphological subtypes are clinically recognised:

Why Atrophic Acne Scars Form: The Pathophysiology PDRN Addresses

Understanding the pathophysiology of acne scar formation explains precisely why PDRN's mechanism is clinically relevant:

Inflammatory acne lesions — papules, pustules, and cysts — trigger an acute inflammatory response in the dermis that, when sufficiently intense or prolonged, destroys collagen fibres in the surrounding tissue. The complement cascade, neutrophil-mediated proteolysis, and macrophage inflammatory signalling all contribute to this collagen destruction. The resulting tissue deficit is the scar.

Normal wound healing would repair this deficit through fibroblast proliferation and collagen synthesis in the repair phase. In acne-related scarring, this repair is inadequate — the inflammatory environment is hostile to normal fibroblast function, and the result is a scar where the dermis has not been fully rebuilt. The deficient collagen architecture is what creates the visible surface depression.

PDRN directly addresses this repair deficit: A2AR activation drives fibroblast proliferation and collagen synthesis in the scar tissue, providing the cellular programme that the original healing response failed to complete adequately. The salvage pathway nucleotide supply also provides DNA and RNA building blocks directly to the proliferating fibroblasts, supporting the energy-intensive collagen synthesis process. The anti-inflammatory A2AR signalling simultaneously suppresses residual chronic inflammatory activity that may still be impeding normal tissue repair — particularly relevant in patients with ongoing or recently resolved acne.

Clinical Evidence for PDRN in Acne Scar Treatment

The evidence base specifically for PDRN in acne scars is growing, supported by the broader wound healing and skin regeneration literature:

Direct Acne Scar Evidence

A controlled clinical study by Kim et al. (2018) in the Journal of Cosmetic Dermatology evaluated intradermal PDRN injection for atrophic acne scars versus saline control, demonstrating significant improvement in scar depth and skin quality scores in the PDRN group at 3 and 6 months. Histological analysis confirmed increased dermal collagen density and improved tissue architecture in treated areas.

A further study by Squadrito et al. (2014) in the European Journal of Pharmacology confirmed the mechanism of PDRN in stimulating collagen synthesis and dermal tissue remodelling through A2AR activation — providing the mechanistic foundation that supports its application in atrophic scar treatment.

Combination Evidence (PDRN + Microneedling)

Multiple Korean clinical studies have assessed PDRN combined with microneedling for acne scars, consistently showing superior outcomes with combination treatment versus microneedling alone. The synergy is mechanistically logical: microneedling creates the collagen induction wound healing stimulus through micro-injury; PDRN provides A2AR-mediated fibroblast support and nucleotide supply to enhance the repair response. Results from combination protocols show greater improvement in scar depth, scar surface area, and overall skin quality than either treatment alone.

The combination evidence is consistent with the principles established in the broader regenerative medicine literature — that the wound healing cascade initiated by physical micro-injury is amplified when biological signalling agents are introduced simultaneously or in close temporal proximity to the injury event.

Patient Selection and Pre-Treatment Assessment

Effective acne scar treatment begins at consultation with a thorough assessment that determines scar type, severity, and the appropriate treatment approach:

Scar Assessment Tools

•        Visual assessment under tangential lighting: Side-directed lighting (torch or ring light at a very shallow angle to the skin surface) casts shadows into scar depressions and reveals topography that is invisible under standard direct lighting. Assess all scars under this lighting before classification.

•        Goodman and Baron grading scale: A validated 4-point scale for acne scar severity — Grade 1 (macular, pigmentary change only), Grade 2 (mild atrophic, visible from 50cm+), Grade 3 (moderate, visible from 50cm, easily concealed by makeup), Grade 4 (severe, visible from 50cm, not easily concealed). PDRN is most appropriate for Grade 2–3 scars as a primary injectable and as an adjunct for Grade 4.

•        Pinch test (for rolling scars): Gently pinch the skin at the scar site between two fingers. If the rolling scar improves or disappears with pinching, it has a significant surface attachment component that would benefit from subcision before or alongside PDRN. If no change with pinching, the scar is likely bound by deeper fibrous adhesions requiring more aggressive subcision.

•        Photography under standardised conditions: Essential for objective outcome documentation. Photograph in frontal, lateral, and three-quarter views under direct lighting AND tangential lighting at baseline and at each review. Tangential light photographs often show improvement that direct-light photographs miss.

Ideal Patient Profile for PDRN Acne Scar Treatment

•        Acne fully controlled or in remission: Active acne in the treatment zone is a relative contraindication — injecting through inflamed skin increases infection risk and the ongoing inflammatory activity counteracts PDRN's regenerative effect. Confirm acne is controlled (not necessarily cleared) before beginning a PDRN scar course. Mild comedonal acne in non-treatment areas is acceptable.

•        Atrophic scar morphology (boxcar or rolling — not ice-pick): As discussed above. Confirm scar type before committing to a protocol.

•        Fitzpatrick skin type I–IV for combination with laser: For patients planning a combination protocol with fractional laser, Fitzpatrick type V–VI requires an experienced practitioner using appropriate laser settings and a longer PDRN-to-laser interval.

•        Realistic expectations: Acne scar improvement is real but gradual — meaningful improvement over a 6-month course rather than transformation after one session. Patients who understand and accept this timeline are the most satisfied.

•        Not isotretinoin (Roaccutane) within 6–12 months: Isotretinoin significantly impairs wound healing and collagen metabolism. The standard guideline is to wait 6–12 months after completing isotretinoin before any procedure that stimulates wound healing (including PDRN injection and microneedling). Confirm this at consultation.

PDRN Injection Protocol for Acne Scars

The acne scar PDRN protocol uses a combination of targeted injection at the scar base and broader intradermal treatment of the surrounding skin zone. The technique differs from standard skin quality nappage in that some injections specifically target individual scars:

Equipment and Parameters

•        Needle gauge: 30G or 31G for nappage across the broad zone. 32G or 33G for precise targeted injection into individual shallow scars.

•        Needle length: 4mm or 6mm. Sufficient for intradermal placement in facial skin.

•        Injection approach: Two techniques combined: (1) Targeted micropapule injection directly into the floor of each scar; (2) Nappage technique across the broader treatment zone (full cheek/forehead/chin as appropriate).

•        Volume per point: Targeted scar injection: 0.01–0.02ml per scar base. Nappage across broad zone: 0.01–0.02ml per point at 1–1.5cm spacing.

•        Product concentration: Standard PDRN concentration as specified by manufacturer. For heavily scarred skin, some practitioners use slightly higher concentration products — confirm with manufacturer guidelines.

The Two-Technique Protocol

Technique 1 — Targeted scar base injection: For each identifiable scar depression, insert the needle at 45–60 degrees and direct the tip toward the scar base (the floor of the depression). Inject 0.01–0.02ml directly into the scar floor at intradermal depth. This places PDRN directly at the site of collagen deficit. A very small papule at the scar site confirms correct placement. Work through all identifiable scar sites in the treatment zone.

Technique 2 — Broad zone nappage: After completing targeted scar injections, treat the entire surrounding skin zone with standard nappage technique (0.01–0.02ml per point, 1–1.5cm spacing). This improves the general skin quality of the scar-bearing skin — the peri-scar tissue environment — creating a better foundation for collagen remodelling and making individual scars less visible against a healthier skin background.

Step-by-Step Session Protocol

1.     Photograph: Standardised photography in direct and tangential lighting at the start of every session before any treatment.

2.     Apply topical anaesthetic: EMLA under occlusion 45–60 minutes pre-treatment. The combination of targeted scar injections and broader nappage makes thorough anaesthesia more important for acne scar treatment than for simple skin quality nappage.

3.     Ice immediately before: Apply ice to each section for 2 minutes before treating that section.

4.     Map the scars: In good lighting (including tangential light), identify and mentally map all scar sites to be targeted. This pre-planning prevents missing scars during the injection sequence.

5.     Targeted scar injection first: Work through each scar site with targeted base injection at 45–60 degrees. Inject 0.01–0.02ml per scar. Apply gentle pressure at each point after withdrawal.

6.     Broad nappage second: Treat the surrounding zone with standard nappage technique, filling in between scar sites and covering the full treatment zone.

7.     Post-treatment cooling: Ice applied gently across the treated zone for 3–5 minutes.

8.     Document: Record the total volume used, zones treated, and any individual scars noted for review at the next session.

Complete PDRN Acne Scar Treatment Protocol

Combination Strategies: When PDRN Works Best Alongside Other Treatments

PDRN produces its best acne scar outcomes when used as part of a coordinated multi-modal approach. The most effective combinations:

PDRN + Microneedling

The most practical and most evidence-supported combination for most aesthetic practitioners. Microneedling creates controlled micro-injury to the scar tissue, stimulating the wound healing cascade and physically disrupting the scar architecture. PDRN administered after microneedling — either topically via the open channels immediately post-procedure, or by injection 2–4 weeks later — provides A2AR-mediated biological amplification of the wound healing response.

•        Same-session approach (topical PDRN): PDRN product applied topically to the skin immediately after microneedling, while the microchannels are open. The PDRN penetrates via the channels and reaches the dermis without injection. This approach does not require an injection license but delivers less PDRN per session than injectable treatment. Some practitioners use a PDRN serum specifically formulated for topical application post-microneedling.

•        Alternating session approach (injectable): Microneedling at Session 1. Injectable PDRN at Session 2 (2–4 weeks later, once channels are fully closed and acute inflammation resolved). This delivers the maximum intradermal PDRN concentration and avoids any infection risk from injecting through open microchannels. Recommended as the safer approach for practitioners unfamiliar with same-session combination.

•        RF microneedling + PDRN: RF microneedling adds thermal collagen contraction to the mechanical micro-injury of standard microneedling. Particularly effective for rolling scars. PDRN minimum 3–4 weeks after RF microneedling due to the more significant tissue response from the thermal component.

PDRN + Fractional Laser

Fractional laser resurfacing — ablative (CO2, erbium) or non-ablative (1550nm, 1927nm) — produces the most dramatic single-modality improvement in acne scar depth of any non-surgical treatment. PDRN's role in combination with laser is to:

•        Prepare the skin pre-laser: 4–6 weeks before fractional laser, a PDRN course improves the baseline skin quality and collagen status, creating a better tissue environment for the laser procedure

•        Accelerate post-laser healing: minimum 4–6 weeks after ablative laser, PDRN supports the wound healing and collagen remodelling phases through its anti-inflammatory and regenerative mechanisms

•        Sustain long-term results: periodic PDRN maintenance after laser maintains the improved scar architecture against the ongoing collagen remodelling that continues for 6–12 months post-laser

For the complete laser and energy device combination protocols, see our post on Combining PDRN with Laser and Energy Devices.

PDRN + Subcision (for Rolling Scars)

For rolling scars specifically, subcision — the physical release of fibrous adhesion bands pulling the scar base downward — is the primary treatment. PDRN's role in combination with subcision is:

•        Post-subcision wound healing support: PDRN administered 2–4 weeks after subcision supports the collagen deposition that fills the space created by the released adhesions

•        Fibroblast stimulation in the subcised zone: A2AR activation drives collagen synthesis at the site of the fibrous band release, improving the quality of new tissue formed as the released scar area elevates

•        Prevention of re-adhesion: sustained fibroblast activity and improved tissue architecture may reduce the risk of fibrous bands re-forming after subcision, though this is not definitively established

PDRN + TCA Cross (for Ice-Pick Scars)

TCA (trichloroacetic acid) Cross — focal application of high-concentration TCA into individual ice-pick scar channels — stimulates a controlled chemical wound healing response that gradually fills the narrow scar channel from the base. PDRN can be used as a supportive treatment in the surrounding skin alongside TCA Cross, improving the general skin quality and collagen environment without being placed in the ice-pick channel itself.

Setting Patient Expectations for Acne Scar Treatment

Acne scar treatment requires the most careful expectation management of any aesthetic indication. Patients with significant scarring often arrive hoping for complete elimination — and honest communication about what is achievable is both ethically essential and practically important for patient satisfaction:

•        Improvement, not elimination: Even the most effective acne scar protocols produce improvement in scar depth and appearance — typically 30–60% reduction in scar severity assessed by objective grading — not complete elimination. Use the Goodman-Baron scale to set this in concrete terms: 'We're aiming to move from Grade 3 to Grade 2 over the treatment course, which represents a meaningful visible improvement.'

•        Timeline: 6 months minimum to see full induction results: The collagen remodelling response to PDRN continues for months after each injection. Assessment at 12 weeks mid-course provides a useful interim progress check, but the full result of a 6-session protocol is typically not visible until 6–8 months after the first treatment.

•        Photography is essential for patient satisfaction: Patients with acne scars are among the most photograph-sensitive in aesthetic practice. Many will not perceive their own improvement because they look at their face every day in a mirror under direct lighting. Tangential light photography at baseline and at 6 months — shown side by side at the assessment appointment — is the single most powerful patient satisfaction tool in acne scar practice.

•        Combination protocols produce better outcomes: A patient committed to a full combination protocol (PDRN + microneedling + potentially fractional laser for Grade 3–4 scars) will achieve better outcomes than PDRN alone. Present the full plan at consultation and allow the patient to choose their level of commitment.

Key Takeaways

•        Scar classification determines treatment appropriateness — PDRN is best suited for boxcar and shallow atrophic scars. Rolling scars need subcision as primary treatment with PDRN support. Ice-pick scars need TCA Cross. Hypertrophic and keloid scars are contraindicated for PDRN.

•        PDRN addresses the fundamental pathology of atrophic scars — collagen deficit from inadequate wound healing. A2AR fibroblast proliferation and collagen synthesis directly rebuild the scar architecture that original healing failed to restore.

•        The two-technique protocol — targeted scar base injection + broad zone nappage — delivers PDRN both at the specific scar sites and to the general skin quality of the surrounding zone.

•        6 induction sessions is the standard for acne scar treatment — scar remodelling requires more sessions than general skin quality improvement because the target is structural collagen architecture, not surface hydration.

•        Combination with microneedling produces superior outcomes — microneedling creates the wound healing stimulus; PDRN amplifies the biological repair response. Alternating sessions with a 2–4 week interval is the most reliable approach.

•        Photography under tangential lighting is non-negotiable — patient perception of improvement correlates poorly with objective improvement in acne scarring. Show the before-and-after tangential light photographs at every review appointment.

•        Korean PDRN products are appropriate for acne scar treatment — CE-marked, MFDS-approved products from Celmade's PDRN and PN range provide consistent pharmaceutical-grade PDRN across the concentration range appropriate for facial and scar applications.

For related guides: Complete Polynucleotides and PDRN Guide, PDRN vs HA Skin Boosters: Patient Selection, and our Combining PDRN with Laser and Energy Devices. Browse Celmade's PDRN and PN collection.

Frequently Asked Questions

Can PDRN completely remove acne scars?

No — PDRN improves acne scar appearance by stimulating collagen remodelling and improving the depressed scar architecture, but it does not eliminate scars. Realistic outcomes with a full 6-session protocol are 30–60% improvement in scar depth and severity, which is clinically meaningful and often represents a significant quality-of-life improvement for patients. Setting this expectation clearly at consultation prevents dissatisfaction regardless of how well the treatment works.

How long does PDRN take to improve acne scars?

Visible improvement begins to emerge at 8–12 weeks after the start of treatment, as the collagen synthesis stimulated by PDRN sessions matures and remodels. The full benefit of a 6-session induction protocol is typically most apparent at 6–8 months from the first session — the collagen remodelling process continues for months after each injection. This slow timeline is one of the most important pieces of information to communicate at the initial consultation, as patients unfamiliar with collagen induction timelines may otherwise assess the treatment as ineffective at 4–6 weeks.

Should I use PDRN before or after microneedling for acne scars?

Both sequences are clinically valid and the choice depends on your practice setup. The safest and most commonly recommended approach for acne scars is alternating sessions: microneedling at Session 1, injectable PDRN at Session 2 (2–4 weeks later), continuing to alternate through the induction course. This avoids any infection risk from injecting through open microchannels and allows each treatment to be clearly assessed. If same-session treatment is preferred, topical PDRN applied via the open microchannels immediately post-microneedling is a lower-risk alternative to injection in the same session.

Is PDRN appropriate for patients with active acne?

Active acne in the treatment zone is a relative contraindication — injecting through inflamed skin increases infection risk, and the ongoing inflammatory environment counteracts PDRN's regenerative mechanism. Confirm that acne is controlled (not necessarily fully cleared — some mild comedonal acne in adjacent areas is acceptable) before beginning a PDRN scar course. If the patient is on isotretinoin currently, defer treatment until 12 months after completing the course.

Which Korean PDRN products are appropriate for acne scar treatment?

CE-marked Korean PDRN products from Celmade's PDRN and PN range include formulations appropriate for facial skin quality and scar treatment applications. For acne scar protocols, standard PDRN concentrations formulated for intradermal facial injection are appropriate. Confirm product-specific concentration and injection guidance with Celmade before commencing treatment. Korean PDRN products are manufactured under MFDS pharmaceutical standards and have an extensive real-world clinical evidence base from the Korean dermatology market — where PDRN-based acne scar treatment has been standard practice for over a decade.