Researchers in Australia have discovered that adding topical estrogen to the penis thickens the layer of natural keratin in the skin, potentially reducing the risk of HIV transmission, the Sydney Morning Herald reports (, 6/4).

Keratin acts as a barrier to virus infection. In a two-week trial, topical estrogen applied to the foreskin enhanced keratin quickly and substantially, researchers said. “We have found a new avenue to possibly prevent HIV infection of the penis,” lead researcher Roger Short said, adding that “in countries where circumcision is not religiously or culturally accepted,” topical estrogen treatments could curb HIV infections.

The article did not address any protection topical estrogen treatments might afford circumcised men.