Intradermal Botulinum Toxin A on Skin Quality and Facial Rejuvenation: A Systematic Review and Meta-analysis

Abstract

Background: Botulinum toxin A (BTxA) has gained popularity as a nonsurgical aesthetic treatment for skin rejuvenation. However, previous studies on intradermal BTxA have shown inconsistent results. This systematic review and meta-analysis with trial sequential analysis aimed to assess the efficacy and safety of intradermal BTxA for facial rejuvenation.

Methods: Following PRISMA guidelines, a comprehensive search was conducted in various databases from January 2008 to March 2023. Outcome measures included sebum production, pore size, skin hydration, skin texture, erythema index, facial wrinkles, and facelift. Eligible studies included human-based clinical trials and prospective cohort studies published in English, focusing on healthy populations requiring facial rejuvenation. Two authors independently screened the titles and abstracts, followed by a full-text review to determine study eligibility. Data extraction and quality assessment were performed by two authors using predefined criteria.

Results: Ten studies met the inclusion criteria, including five randomized controlled trials and five prospective cohort studies with 153 participants. Studies revealed positive effects of intradermal BTxA on various outcome measures related to facial rejuvenation. These effects included improvements in sebum production, pore size, erythema index, facial wrinkles, skin texture and elasticity, and overall facelift but not skin hydration. All failed to reach the required information size in the trial sequential analysis.

Conclusions: Findings suggest positive outcomes in multiple attributes of skin quality and facial rejuvenation. However, more high-quality research is needed to establish definitive conclusions. These findings contribute to the evidence base for nonsurgical aesthetic treatments, emphasizing the importance of ongoing research in this field.

Fig. 1.

PRISMA flow diagram.

Fig. 2.

Risk of bias summary: review of authors’ judgements about each risk of bias item for included RCTs.

Fig. 3.

Overall risk of bias graph presented as percentages across all included RCTs.

Fig. 4.

Funnel plot for the publication bias of the included studies. SE: Standard error.

Fig. 5.

Comparison of BTxA with control for the skin attribute changes. IV, inverse variance.

Fig. 6.

TSA of trials explored the effectiveness of BTxA in the reduction of sebum production. The cumulative Z-curve has not crossed the RIS (189) but crossed conventional benefit boundary.

Fig. 7.

TSA of trials explored the effectiveness of BTxA in the reduction of pore size. The cumulative Z-curve has not crossed the RIS (2499) but crossed conventional benefit boundary.

Fig. 8.

TSA of trials explored the effectiveness of BTxA in improvement of skin hydration. The cumulative Z-curve has not crossed the RIS (89) but crossed conventional benefit boundary and touched area of futility, indicating that any future meta-analysis is unlikely to show a significant difference, even though more clinical trials may be conducted until the RIS is achieved.

Fig. 9.

TSA of trials explored the effectiveness of BTxA in improvement of skin texture. The cumulative Z-curve has not crossed the RIS (450) but crossed conventional benefit boundary.

Fig. 10.

TSA of trials explored the effectiveness of BTxA in improvement of erythema index. The cumulative Z-curve has not crossed the RIS (99) but crossed conventional benefit boundary.

Fig. 11.

TSA of trials explored the effectiveness of BTxA in improvement of wrinkles. The cumulative Z-curve has not crossed the RIS (99) but crossed conventional benefit boundary.

Fig. 12.

TSA of trials explored the effectiveness of BTxA in facelift. The cumulative Z-curve has not crossed the RIS (120) but crossed conventional benefit boundary.