Nike has an invite-only celebrity gym with kale juice on tap - here's what it's like to work out there

In New York's trendy Soho neighborhood, there's an unassuming building on Grand Street that says "by appointment only."

It bears Nike's signature check mark.

Welcome to 45 Grand, Nike's exclusive, invite-only gym. Models like Karlie Kloss have worked out here.

Nike says that influencers and active Nike Plus members are invited to join world class trainers on personal "journeys," where trainers construct workouts designed to meet each individual's needs.

Nike invited Business Insider to check out the facilities, and even let me get a grueling personalized workout.

It's tough to get an invite, but you can get a firsthand look here.