Though certain online fashion subscription services might already be upending their business models, the monthly beauty niche is going strong.  Birchbox, one such start-up in the category, reached 100,000 subscribers after launching in September 2010.  And now they’re expanding to reach the boys.

A sampling of Birchbox products, among other manly items.

Birchbox sends out once-a-month surprise packages of highly curated, deluxe-sized samples to its members, who can subscribe to the service on month-to-month, six month, or year-long bases.  The Birchbox Shop provides full-sized versions of all the products sent as samples.  Now, for $20 a month, men can receive the same prestige level of mini grooming supplies, culled from brands like Kiehl’s, John Varvatos, and Marvis.

For women, it makes sense to offer monthly samples as a way to explore new products and learn about a variety of brands.  We expect this part of the business appeals to some of Birchbox’s future male audience.  But how many guys do you know who particularly like having to add “buy shaving cream” to their to-do list?  Not that many, right?  For them, signing up for a monthly product subscription service might hold mere practical appeal.  But hey, if it gets the male audience in the door, then Birchbox’s model works.

Another reason Birchbox might be expanding while other subscription services are forced to re-tool their model — it’s plausible that the kind of consumer who can and will pay for monthly prestige beauty samples might also be prone to travel, and travel often.  If so, man or woman, all those mini products scattered around the bathroom take on a new kind of utility, don’t they?