Bold claim: Post-acne redness doesn’t have to mean dull, persistent skin—intruder intradermal botulinum toxin A may offer faster, more noticeable relief than light-based therapy. But here’s where it gets controversial: the evidence comes from a single-center, small split-face trial, so results should be interpreted with caution.
Overview of the study design
Post-acne erythema is a common concern for people whose inflammatory acne has settled but who still battle facial red patches. In this Chinese study, 30 adults with post-acne erythema were recruited for a within-subject comparison. Each participant received two different treatments on opposite cheeks: one cheek was given a single intradermal injection of botulinum toxin A, while the other cheek underwent three broadband light (BBL) sessions at one-month intervals.
Researchers tracked multiple objective and clinical outcomes from baseline through three months of follow-up. Measurements included the Clinician Erythema Assessment (CEA) score, erythema index from imaging, colorimetric a* values, sebum output, transepidermal water loss (TEWL), skin hydration, and adverse events. Pain was measured with a visual analog scale, and patient satisfaction was recorded for both sides.
What happened over three months
At baseline, the two treatment sides were comparable in characteristics. One month after treatment, cheeks treated with intradermal botulinum toxin A showed significantly greater improvements in CEA, erythema index, a* values, and sebum reduction compared with the BBL-treated cheeks. The botulinum toxin A side maintained the sebum reduction advantage at both two and three months. Additionally, the injection side continued to show a greater CEA reduction at two months and a more pronounced improvement in a* values at three months.
Both therapies demonstrated overall trends toward reduced erythema index, TEWL, CEA scores, and sebum, with improved skin hydration relative to baseline. In other words, each modality contributed to redness and texture improvements, though intradermal botulinum toxin A produced faster and more substantial changes in several parameters.
Safety and patient experience
Pain was higher with intradermal botulinum toxin A due to the multiple injections, whereas BBL was less painful. Despite the higher discomfort with injections, patient satisfaction did not differ significantly between sides, and safety appeared comparable across groups, with no major adverse events reported during the three-month follow-up.
Clinical implications for practitioners
For clinicians treating patients troubled by persistent facial erythema and residual acne scars, intradermal botulinum toxin A emerges as a promising option that may deliver meaningful redness and sebum reductions from a single session. However, the study’s small size, single-center design, and short follow-up limit the ability to generalize findings to broader patient populations or longer-term outcomes.
Future directions
Larger, multi-center trials with longer follow-up are needed to determine whether intradermal botulinum toxin A can be reliably integrated into routine management of post-acne erythema and how it compares with other standard therapies over the long term.
Reference: Yang L et al. Efficacy and safety of intradermal botulinum toxin A for post-acne erythema: a split-face randomized controlled trial. Front Med. 2025;12:1610125.
Note: This summary reflects the study's reported data and interpretations. For clinicians and patients considering treatment options, discuss individual risks, benefits, and preferences before deciding on a plan.
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