A Bold Take: Intradermal Botulinum Toxin A may beat broadband light for treating post-acne redness, offering a faster path to clearer skin. But here’s where it gets controversial: this conclusion comes from a small, single-center study, so wider confirmation is essential before changing standard practice.
What the study did
In a Chinese center, 30 adults with post-acne erythema participated in a split-face trial. Each participant received two different treatments on opposite cheeks: one cheek got a single intradermal injection of botulinum toxin A, while the other cheek underwent three broadband light sessions at one-month intervals. Researchers tracked a range of outcomes over three months, including Clinical Erythema Assessment (CEA) scores, imaging-derived erythema indices, colorimetric a* values, sebum production, transepidermal water loss (TEWL), skin hydration, and any adverse events. Pain was measured with a visual analog scale, and patient satisfaction was recorded for both sides.
Key findings over three months
- At one month, the intradermal botulinum toxin A side showed significantly greater reductions in CEA, erythema index, a* value, and sebum secretion compared with the broadband light side.
- The botulinum toxin A side maintained superior sebum reduction at two and three months.
- Improvements in CEA persisted as greater on the injection side at two months, and the a* value improvement remained greater at three months.
- Both treatments trended toward lower erythema indices and TEWL, with improved skin hydration and reduced sebum secretion relative to baseline. In other words, each modality can help with post-acne erythema, but intradermal botulinum toxin A delivered faster and more pronounced changes in several metrics.
Safety and patient experience
Pain was higher with intradermal injections due to the multiple needle pokes, while broadband light was more comfortable. Despite the higher pain with injections, patient satisfaction did not differ meaningfully between the two treatments, and there were no concerning adverse events reported over the three-month follow-up. The overall safety profile appeared similar for both approaches.
Clinical implications and caveats
For clinicians treating patients troubled by persistent facial redness after inflammatory acne, intradermal botulinum toxin A emerges as a promising option that may deliver redness reduction and sebum suppression with a single session. However, the study’s limitations—small sample size, single-center design, and short duration—mean these results should be interpreted cautiously. Larger, multi-center trials with longer follow-up are needed before intradermal botulinum toxin A can be widely adopted into routine acne management.
Bottom line
This research suggests intradermal botulinum toxin A can outperform broadband light for post-acne erythema in the short term, while both modalities offer meaningful improvements. The take-home message is that intradermal botulinum toxin A is worth watching as a potential option, but it isn’t yet ready to replace established treatments across the board without further evidence.
Source: 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.
