By Dr. Liji Thomas, MD Reviewed by Lauren Hardaker Nov 25 2025 A breakthrough zwitterionic polymer slips through the skin’s toughest barriers, carrying insulin deep into tissue and normalizing blood sugar, offering patients a painless alternative to daily injections. Study: A skin-permeable polymer for non-invasive transdermal insulin delivery. Image credit: Me dia/Shutterstock.com A recent study published in the journal Nature examines the use of the skin-permeable molecule poly[2-( N -oxide-