JOSIE MARAN has landed some of the world's most competitive modeling gigs: the Sports Illustrated swimsuit issue, the Victoria's Secret catalog, and cover after cover of Glamour, Maxim, Self, and other big-name glossies. These days, though, the porcelain-faced beauty, 33, focuses on promoting her eco-makeup brand (josiemarancosmetics.com) and raising her 5-year-old daughter, Rumi Joon. A chunk of the proceeds from her company goes to a variety of charities, including ones that help protect polar bears and argan forests.

Q: What inspired you to start an eco-makeup line?

A: I used to ask makeup artists, "Is there anything that's healthier or more natural?" and they'd always say it's impossible to do. I wanted it for myself, and I didn't understand why it couldn't be done. So I did it.

Q: How?

A: I went to a lot of conferences. I talked to people in the natural-beauty realm about ingredients, and they introduced me to labs. So I went to the labs with all the makeup that I wanted but that I considered toxic and said, "I want all these products but without the bad stuff." I worked on my line for three years with four labs and lots of chemists. It took a long time because they'd never done that before—pulled out those ingredients to make a good product.

Q: Which ingredients didn't you want in there?

A: I really think the most toxic ingredients in the world are synthetic fragrances. None of my products have synthetic fragrances. Or parabens or talc or phthalates. I also do my best not to have petrochemicals.

Q: What's your best beauty tip?

A: Less is more.