Abstract
This systematic literature review and meta-analysis evaluated the efficacy of oral aloe vera supplementation on skin aging parameters including wrinkles, hydration, elasticity, transepidermal water loss (TEWL), and collagen score. We searched MEDLINE, EMBASE, AMED, PubMed, CINAHL, CENTRAL, and trial registries up to July 2024 for randomized controlled trials. Four RCTs (n=284 participants) met the inclusion criteria. Compared with placebo, aloe vera supplements had little to no effect on skin hydration after 4 weeks (SMD, 0.61; 95% CI [-0.55, 1.77]), 8 weeks (MD, 0.58; 95% CI [-0.70, 1.87]) or 12 weeks (SMD 0.69; 95% CI [-0.82, 2.19]). Similarly, TEWL, elasticity, and collagen scores did not differ significantly from placebo. The certainty of the evidence for all assessed outcomes is low due to concerns regarding imprecision, and inconsistency. A marginal reduction in wrinkle width was observed in adults ≥40 years, but this was based on a single study. Heterogeneity in formulations (19–40 µg sterols), small sample sizes, and short trial durations (≤12 weeks) limited the robustness of conclusions. While preclinical data suggest Aloe vera sterols may stimulate collagen synthesis, clinical evidence remains inconclusive. Current evidence does not support oral Aloe vera as an effective intervention for skin aging, though subgroup-specific effects warrant further investigation.