A Topical Parathyroid Hormone/Parathyroid Hormone-Related Peptide Receptor Antagonist Stimulates Hair Growth in Mice

In a study from 2007, researchers investigated the potential of a topical cream containing the parathyroid hormone/parathyroid hormone-related peptide (PTH/PTHrP) receptor antagonist, PTH (7–34), to stimulate hair growth in mice. The cream was applied daily for one week to the backs of 5-week-old female SKH-1 hairless mice. The results showed a significant increase in hair growth, with treated mice exhibiting 216% longer hairs, 40% more visible hairs, and 43% more hair follicles in the growth phase compared to controls, all with statistical significance (P < 0.001 for hair length and visible hairs, P < 0.01 for hair follicles). This study was the first to demonstrate the effectiveness of a topically applied PTH/PTHrP receptor antagonist on hair growth in vivo, suggesting a new approach for developing topical treatments for hair growth disorders.