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Skin Biostimulation for Scars and Stretch Marks: Frequently Asked Questions

November 26, 2025
Skin Biostimulation for Scars and Stretch Marks

Skin biostimulation is a regenerative technique that restores skin quality by stimulating collagen and elastin production. Used to treat scars and stretch marks, biostimulatory injectables, such as calcium hydroxylapatite (CaHA), poly-L-lactic acid (PLLA), and platelet-rich plasma (PRP), enhance dermal remodeling and elasticity. Supported by emerging clinical evidence, these treatments offer long-term improvement in texture and tone. This FAQ provides evidence-based guidance for clinicians on current best practices in skin biostimulation. 

1. Do collagen “biostimulators” (PLLA/PDLLA, CaHA) improve stretch marks? 

Emerging evidence supports their role in improving skin texture and elasticity in striae distensae. Hyper-dilute CaHA with microneedling and ascorbic acid improved stretch marks through neocollagenesis and neoelastogenesis in a retrospective study.1,2 Similarly, poly-D,L-lactic acid (PDLLA) micro-jet protocols demonstrated visible improvement across 5 treatment sessions.3 Although these studies are small and largely nonrandomized, their mechanistic basis—stimulation of fibroblast activity and dermal remodeling—is well supported.2 Patients should be advised that improvements are gradual and data remain preliminary. 

2. Is PRP or PRF effective for striae distensae? 

PRP and platelet-rich fibrin (PRF), when combined with microneedling, appear to enhance collagen remodeling in striae. A randomized split-abdomen trial found both modalities improved abdominal striae appearance after 3 monthly sessions with minimal adverse effects.4 However, a systematic review concluded that the overall quality of evidence remains low due to heterogeneity in protocols and endpoints.5 Combination approaches, such as PRP with laser or biostimulatory fillers, may yield superior outcomes. 

3. Which injectables have the strongest evidence for atrophic acne scars? 

Biostimulatory fillers, especially CaHA and PLLA, have demonstrated efficacy in atrophic acne scars, particularly rolling scars.6 Optimal outcomes often require multimodal treatment, such as subcision or fractional resurfacing.7 Evidence supports the ability of CaHA and PLLA to induce neocollagenesis and improve contour defects, with improvements lasting beyond 12 months in some studies.6 

4. What treatment intervals and downtime should clinicians discuss with patients? 

Treatment frequency depends on the product and modality. PDLLA protocols generally use 5 sessions spaced 4 to 6 weeks apart,3 whereas PRP/PRF microneedling protocols typically require 3 monthly sessions.4 Hyper-dilute CaHA for dermal remodeling is often repeated every 6 to 12 months based on skin response.2 Expected downtime is minimal, with transient erythema, edema, or bruising typically resolving within 24 to 48 hours. 

5. What are the main risks and complication management strategies for biostimulators? 

Most reactions are mild and transient. However, delayed nodules and granulomatous reactions have been reported with CaHA and PLLA/PDLLA injectables.8-10 Prevention includes proper dilution, micro-aliquot deposition, and adequate post-injection massage for PLLA/PDLLA.9,10 For CaHA, focal nodules can be treated with mechanical disruption, saline lavage, or intralesional corticosteroids ± 5-fluorouracil.8 Serious vascular occlusion is rare but requires standard filler safety precautions.

References  

  1. Casabona G, Marchese P. Calcium hydroxylapatite combined with microneedling and ascorbic acid is effective for treating stretch marks. Plast Reconstr Surg Glob Open. 2017;5(9):e1474. doi:10.1097/GOX.0000000000001474 
  2. Amiri M, Meçani R, Niehot CD, et al. Skin regeneration-related mechanisms of calcium hydroxylapatite (CaHA): a systematic review. Front Med (Lausanne). 2023;10:1195934. doi:10.3389/fmed.2023.1195934 
  3. Seo SB, Kim SB, Yi KH. Effective improvement methods for striae distensae: a novel approach utilizing laser-induced micro-jet injectors with poly-D,L-lactic acid. J Cosmet Dermatol. 2024;23(9):2876-2881. doi:10.1111/jocd.16366 
  4. Ahmed AEM, Mahmoud WA, El-Komy FBY. Microneedling with autologous platelet-rich fibrin versus microneedling with platelet-rich plasma in treatment of abdominal stretch marks: a randomized comparative study. Arch Dermatol Res. 2025;317(1):602. doi:10.1007/s00403-025-04135-9  
  5. Sawetz I, Lebo PB, Nischwitz SP, et al. Platelet-rich plasma for striae distensae: what do we know about processing autologous blood contents for treating skin stretch marks? A systematic review. Int Wound J. 2021;18(3):387-395. doi:10.1111/iwj.13541 
  6. Albargawi S. Synthetic dermal fillers in treating acne scars: a comparative systematic review. J Cosmet Dermatol. 2025;24(1):e16752. doi:10.1111/jocd.16752 
  7. Zhang M, Liu C, Zhang S, Chu R, Ren X. Advances in the treatment of acne scars. Front Med (Lausanne). 2025;12:1643035. doi:10.3389/fmed.2025.1643035 
  8. McCarthy AD, Berkowitz S, Chernoff WG. Successful treatment of noninflammatory CaHA nodules using focused mechanical vibration. Aesthet Surg J Open Forum. 2024;6:ojae018. doi:10.1093/asjof/ojae018 
  9. Storer M, Euwer R, Calame A, Kourosh AS. Late-onset granuloma formation after poly-L-lactic acid injection. JAAD Case Rep. 2016;2(1):54-56. doi:10.1016/j.jdcr.2015.11.017 
  10. Seo SB, Kim SB, Yi KH. Delayed occurrence of foreign body reaction caused by poly-L-lactic acid with monitoring through ultrasonography. Skin Res Technol. 2024;30(4):e13683. doi:10.1111/srt.13683 
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