With the surge of interest in eco-friendly and ethical fashion options over the last few years, many athleisure, yoga and loungewear brands have become popular. But when it comes to performance-level athleticwear, mainstream names still rule.

It’s difficult to find ethically-produced and eco-friendly sportswear labels–even small ones. And in my journey to create such a brand, I’ve found myself puzzled as to why this might be. 

Here’s my theory: Performance-level gear has to be top notch. You can’t run a marathon in shorts that ride up or fall apart after the first wear, so most runners find what works and stick to it. And I don’t blame them! Plenty of surprises can pop up on race day without worrying about whether your gear will hold up. Technical and wicking fabrics are simply necessary for some activities where sweat is involved (and chafing risk is high). If it ain’t broke, don’t fix it, right?

Right. Except that I believe runners and athletes deserve sustainable and ethical options, and that more of them would buy this type of product if they knew that a) it existed and b) it was the same quality as their usual brands. Athletes tend to be a pretty altruistic bunch–a personal observation that’s supported by the increasing number of running events with a charitable giving component within the last decade.

So, as an athlete, what should you look for if you’re interested in finding sustainable workout gear? Here’s my abbreviated guide to sustainable materials that are suitable for serious workouts.

Recycled Fabrics
If you’re a runner, you probably run in a synthetic material like polyester or nylon, spandex or some combination of the two. Spandex on its own is not a sustainable fabric, but it’s incredibly useful as a performance material. Luckily, many blended fabrics contain small amounts spandex, typically 12 percent or less, with the rest made up of the recycled synthetic. Some fabrics that fall into this category include: 

Repreve: Recycled polyester has boomed in the last decade with the development and success of Repreve, a high-quality material made out of recycled water bottles. Some bigger brands are starting to use Repreve in a few of their products.

RPET: A generic version of Repreve commonly referred to as either PET or RPET, this material offers a similar fabric content without the brand name.

Vita: Made by Carvico, Vita is a blended fabric partially made from recycled fishing nets. While innovative, it’s mostly suitable for water sports right now–triathletes and swimmers, you’re in luck!

Natural Fibers
Natural fibers like bamboo, hemp and soy can also be friendlier to the earth and to those producing the material than their traditional counterparts.

Bamboo is a soft, abundantly available fabric that does not require the use of harmful pesticides. Hemp is a durable fabric that doesn’t require a lot of water to produce–and while it’s being grown, it absorbs carbon dioxide. Soy fabric has a “closed-loop” process, so that any waste produced is reused in the next production cycle.

In order to make bamboo, hemp or soy fit for performance-level, spandex is again added. Most of these blends result in lightweight, slightly stretchy and smooth fabrics. I personally use this type of blend for workouts where I know there will be a lot of humidity, because they’re highly absorbent (great for wiping away sweat)!

These are just some of the features of some of the options, and it’s important to note that there is no “perfect” fabric or material that exists yet for sportswear. Information on how to find sustainable activewear is sparse, but retailers are required to list fabric content on product labels–so now you at least have an idea of what to look for. I encourage all eco-conscious athletes to join me in learning about the best way forward for a more sustainable activewear industry.

Update (4.26.16): Cause I Run’s Kickstarter campaign is live. Support it here.