If there is an age requirement and sold behind the counter by the druggist then I don't have a big problem with it. It should only be sold to adults that can fully understand all the risks in taking it.
Sure, in theory, only adults could buy it because only adults would need it, right ... in a perfect world. But, in a perfect world, there would be no need for a product such as this anyway. It's not a perfect world.

So, a fourteen year old having sex shouldn't be allowed access to this product? It would be a million times better if fourteen year olds didn't have sex at all, no argument there. Reality check: fourteen year olds have sex. Thirteen year olds have sex. Twelve year olds have sex. Such is our world.