Hafsa Azam shows her work on her own hands.[Photo by Cai Muyuan/ China Daily]

"I never thought that it could be a business in Beijing," Azam says.

The henna gives off an herbal fragrance, and when it first touches the skin has a cooling effect. As the paste dries, it can be rubbed off the skin and leaves a reddish color.

"The warmer your skin is the darker color you get," Azam says. "It continues to get darker over two days, then it takes about two weeks or so to fade away as the dye comes off with your body's dead skin."

Seizing the business opportunity, Azam launched henna as a side career in 2012 while studying for her bachelor's degree, displaying her designs on the internet.

"I don't usually follow the pictures completely, because no two sets of hands or skin types are the same. I like to follow my intuition."