Evidence Level
Oral phytoceramide supplementation is a relatively novel approach supported by moderate evidence. Guillou et al. (2011) conducted the most rigorous trial, demonstrating that 350 mg/day of wheat-derived phytoceramides significantly improved skin hydration and reduced transepidermal water loss over 12 weeks in a double-blind RCT. Japanese studies on rice-derived ceramides (Asai & Miyachi, 2003) showed similar improvements in skin texture at lower doses. The mechanistic basis is well-understood: dietary ceramides are absorbed, processed in the liver, transported to the skin via lipoproteins, and incorporated into the stratum corneum lamellar structures. Ceramide levels decline with age and are notably deficient in atopic dermatitis, providing a rationale for supplementation.