The combined use of dermaroller and trichloroacetic acid (TCA) 15% was more effective in post-acne atrophic scars than the use of dermaroller and platelet-rich plasma (PRP) or dermaroller only, according to a recent study. 24 volunteers with post-acne atrophic scars were randomly divided into 3 equal groups according to performed procedure on each side of the face (microneedling by dermaroller alone or combined with PRP or TCA 15% peeling) and received 6 bi-weekly sessions of treatment. Photography and punch biopsies were taken before and after 3 months of treatment for clinical, histological, and histometrical evaluation. Researchers found:

• Combined treatment of dermaroller and PRP or dermaroller and TCA 15% showed significant improvement when compared with dermaroller alone.
• Epidermal thickness showed statistically significant increase in studied groups, mainly after dermaroller and TCA 15%.
• Moreover, the 3 studied groups showed more organized collagen bundles and newly formed collagen formation and markedly decreased abnormal elastic fibers.