I really don't mean to be mean, but...why?
Why does it make you loser? I don't see it.
Why do you need to hide it?
I have no close friends either. I also don't have a family or a relationship and I hadn't in a while. I make absolutely no effort to hide it, in fact I made a joke about bringing my cats to an event where we were supposed to bring SO/families at a meeting where pretty much all of my co-workers were present and it didn't even cross my mind that I might be humiliating myself. I have yet to experience anyone having a negative reaction to me saying I don't have friends or family. The only thing I can think of is that women my age don't include me in most of their conversations because many things they are discussing have to do with family, but I don't see why you or me would want to be included into chatter about babies and picking family vacations.
In fact, if you ask me if my co-workers have a family and/or friends, the honest answer in most cases would be "probably, but really I don't know and I don't care", and I'm fairly sure that the feeling is mutual, because people forgotten if I was married multiple times before. Your co-workers wouldn't care either, they simply aren't invested in whatever is happening in your life as long as it has nothing to do with your work. Unless you befriend them, but then you wouldn't be able to say you have no friends, right?