Proper skin hydration is dependent on natural hygroscopic agents including HA,(3) which is produced by HAS and destroyed by HYAL. HAS produces HA by alternately incorporating two UDP-sugar substrates, UDP-N-acetylglucosamine and UDP-glucuronic acid in the cytoplasm. HA is then secreted via an ABC transporter system. HYAL1 can digest HA into tetrasaccharides while HYAL2 cleaves high molecular weight HA into disaccharide units.(22) We observed that BS increased HA levels in HDF cells, but did not alter HAS1, HAS2, HAS3 or HYAL1 mRNA expression. However, BS did appear to inhibit HYAL2 mRNA and protein expression levels.