Nowadays in fashion, the words “eco-friendly,” “organic” and “sustainable” get bandied around a lot. Which is a good thing. Except that sometimes it can be hard to tell the difference between a brand that’s actually helping to make the planet a better place–and one that’s just riding the eco bandwagon with a less-than-well intentioned “organic” label.

“Yes [companies are cashing in on consumers' growing environmental awareness by labeling their clothes "green," without actually changing their production process too much],” Timo Rissanen, Parsons‘ Assistant Professor of Fashion Design and Sustainability, told me. “The industry on the whole and marketing in particular have little integrity.”

“‘Green’, ‘eco’, ‘sustainable’ and the rest are nice but meaningless, feel-good marketing terms,” he added.

Part of the reason why it’s so hard to put your finger on what a brand is actually doing to help the planet is because for many of the “eco” terms, there’s no one definition. “‘Sustainable design’ could mean any number of things,” Rachel Miller, who teaches sustainable design in the Department of Fashion Design at Pratt Institute, said. “It could be about preserving the environment, it could be about ethics and fair wages, it could be a designer that has an interest in designing with organic materials, or it may be recycling what’s already there, using recycled materials to create something new.”

And one “feel-good” marketing term does not necessarily imply the whole gamut. For instance, Miller explained to me, a company that uses organic cotton could be manipulating labor laws in less than savory ways and likewise, items labeled fair trade are not necessarily environmentally friendly.

It’s also important to remember that even the best environmentally-friendly products will have a less-than-great impact on the planet. For instance, trucks and in many cases, planes, are still used to transport “eco” goods, and even garments labeled “100% organic” will use a polyester thread. In other words, it’s not smart to use Earth Day as a reason to go shopping–even if it is all “eco-friendly.”

“Not buying [clothing] is best [for the environment],” Rissanen says. “Buying second-hand is second best.” But buying sustainably-designed clothes is certainly third best. Which is nothing to poo-poo: The earth needs all the help it can get.

But just because there is some clever (and not necessarily altruistic) marketing going on, doesn’t mean you can’t feel good about eco-fashion. And it doesn’t mean there aren’t brands out there who are legitimately doing their part to help the planet, taking a holistic approach to sustainable design.

Read on for the 10 best environmentally-friendly brands who are helping to save the world one sale at a time.