An HPR-containing gel for mild acne

Ninety-four people aged 15 to 40 with mild to moderate facial acne applied a gel containing 0.1% hydroxypinacolone retinoate, 1% encapsulated retinol and 2% papain, once daily for twelve weeks. Acne severity scores fell by about 41% and total lesion counts by about 41%. Nobody dropped out. Two things make this study more useful for what it says about tolerability than about effectiveness. There was no control group and no blinding, so there is nothing to compare the improvement against, and the authors wrote plainly that a controlled study is needed to confirm the result. And the gel contained three active ingredients, so none of the benefit can be assigned to HPR. The tolerability figure is the useful part: 15% of people reported dryness, peeling, redness or burning on a formula containing only 0.1% HPR. That is worth weighing against the widely repeated claim that HPR does not irritate.