Last year we did a deep dive into some of the cleanest t-shirts we could find, but we didn’t do the math.

Made from undyed, unbleached, organic cotton, these garments are free from the hazardous chemicals that are too often found in clothing.  

These products might be clean for the users, but what about for the environment? Are some clean shirts cleaner than others? To answer these questions we collaborated with carbon management platform, Arbor, to estimate and compare the carbon footprints of each product.

Clean fashion needs clean materials

Clean fashion is not just a trend but a necessity, and it’s generally known that materials are the most important factor.

As consumers become increasingly aware of the environmental impacts of their purchases, the demand for clean fashion has skyrocketed. Here we compare six shirts from four different countries to see how their footprints compare.

The global shift towards sustainable clothing is a response to the growing evidence of the textile industry's vast environmental impact, which ranges from excessive water usage to pollution from textile dyeing. This pivot reflects a collective desire to mitigate environmental damage and support a more sustainable future. As such, many of us are actively seeking out brands that prioritize eco-friendly materials, underscoring the urgent need for the fashion industry to adopt more sustainable practices.

Understanding carbon footprint in fashion

We used a cradle-to-gate approach to understand the impacts created before the product reaches the consumer.

A cradle-to-gate life cycle analysis looks at the total carbon dioxide emissions through the beginning of the garment's life cycle, from the raw material extraction, to production, up to the point where the product is ready to leave the factory. Notably it does not include distribution, use, or disposal.

There are many ways to do a lifecycle analysis, and with all these different methods, it is challenging to compare the results. This means that it can be nearly impossible to accurately compare the impact of similar products from different companies. Our goal here is to align the way we calculate impact across different brands to gain a better understanding of how products stack up against each other.

Our analysis, it's crucial to note, is based on publicly available data and does not delve into the specifics of each brand's supply chain or proprietary practices. The carbon emissions calculated encompass only the production and transportation activities associated with creating the shirt, explicitly excluding packaging or any accessories that might accompany the final product, as well as transportation to the customer. Carbon offsets have not been considered in the calculations. Read our full disclosure here. This method allows us to maintain a focus on the core activities responsible for the majority of emissions during the early stages of a garment's life.

Location can be everything

The origin of a garment's materials, and the location(s) of its manufacture are key factors for environmental impact.

Different countries have varying regulations, resources, and technologies related to sustainable fashion and farming, and this influences the carbon footprint of their products. By analyzing shirts made in the United States, India, Peru and Portugal, we can see the significant impact of location and local practices on sustainability performance.

Transportation is the other big factor in a garment's carbon footprint. Some garments are made near where the raw materials are grown, but too often the raw materials, and each step of manufacturing, from ginning, to yarn spinning, knitting, and sewing can all be done in different places around the world. And when you add dropshipping into the equation, the environmental cost of a garment produced around the globe can be multiples higher.

The shirts: a comparative study

The six shirts selected for our analysis represent some of the best examples of organic cotton t-shirts made to minimize the environmental costs of fashion. By examining each brand's materials, production processes, and sustainability initiatives, we offer an overview of how different approaches to clean fashion contribute to the overall goal of reducing the industry's carbon footprint.

Harvest and Mill - 2.13 kg CO2e

The only producer on this list that makes colored garments without dye, Harvest and Mill is unique for their use of heirloom colored cotton, which is cotton that grows with color built-in. They also have plenty of undyed products in the natural color you would expect from undyed, unbleached cotton.

Read more about Sally Fox, who grows these historic cotton breeds in the US.

• Good on You rating: 5/5 Great
• Price: $48.00
• Organic cotton grown in USA, yarn spun and knit in USA, sewn in San Francisco Bay Area
• Undyed and unbleached
• Carbon emissions are offset via reforestation and wind farming

Products: Men’s Crew, Women’s Heirloom Brown Crew

Industry of all Nations - 1.93 kg CO₂e

The coolest brand on this list has a supply chain based in a single province in India, Tamil Nadu, which is a global textile and garment manufacturing center, producing 2-3% of the world's garments. IOAN offers a wide range of undyed unbleached organic cotton garments, and if you want some color, they use naturally fermented indigo to dye a handful of their products, and also offer “wild” cotton garments, made from naturally pigmented cotton grown in Peru.

It’s worth noting that Tirupur, Tamil Nadu’s nexus of garment production was notorious for their polluting dye and bleach houses until 2012, when, after a court order, the producers achieved zero wastewater discharge (this has mostly been maintained since then)

• Price: $40
• Good on You rating: 3/5 it’s a start.
• Undyed and unbleached
• Grown and manufactured within Tamil Nadu, India.

Products: Crewneck T-shirt, Canvas Pants, Cropped T-shirt, Pique Tank, and many more.

ISTO - 4.60 kg CO₂e

ISTO is a Portuguese clothing brand that uses organic and recycled materials. Their products are GOTS-certified and produced in Portugal using materials from Europe, Asia, and the Americas. ISTO offers a ton of supply chain transparency. You can see where all of their materials come from and the factories where they are produced.

Good on You rating: 4/5 Good

• T-shirt Price: $45
• GOTS certified
• Made in Portugal

Products: Classic T-shirt, Denim Work Jacket

Rawganique - 2.56 kg CO₂e

Rawganique is the OG organic clothing brand, specializing in undyed and natural fiber clothing in 1997, including cotton, linen, and hemp. Rawganique's undyed organic t-shirts are grown, spun, and sewn in the USA (Texas and South Carolina) with no sizing or stabilizing chemicals. Rawganique also offers many products sans-elastic that would otherwise include spandex or latex.

• Price: $25.00
• Uses organic cotton grown on a small farm in Texas.
• Cotton is ginned and spun in North Carolina and sewn in South Carolina
• No sizing or stabilizing chemicals

Products: Parker W’s T-shirt, Sonoma M’s T-shirt

The Big Favorite - 2.30 kg CO₂e

The Big Favorite's relaxed, quality pieces are made in Peru, saving significant water, energy, and CO2 emissions from dyeing while providing fair wages. Vogue and The Strategist recommend The Big Favorite's ultra-soft undyed tees as a versatile wardrobe staple. TBF also has some awesome naturally dyed pieces in colors bright enough to defy any natural stereotypes.

• Price: $36.00
• Grown and manufactured in Peru
• Carbon Neutral via Cool Effect.
• Take-back program via ForDays

Products: Undyed Relaxed Crew, lots of underwear

Aya - 1.88 kg CO₂e

Similar to The Big Favorite, Aya makes all of its organic cotton clothing entirely in Peru, from sourcing to sewing, and ships directly to the US and Europe to minimize environmental impact. Aya also features some natural dyes including indigo and eucalyptus (gray).

• Price: $30
• Grown and manufactured in Peru
• OEKO-TEX Finishing, GOTS ink on labels

Products: T-shirt - M’s, T-shirt - W’s

Growing practices and local production make the difference

Most of the impact for a t-shirt comes from the material and it’s growing practices.

Transport can be a key factor if the materials are being shipped and processed in different places around the world. Transportation from the factory and distribution to customers can also tack on a significant piece of carbon, but we’re not calculating that here.

The garments with the lowest carbon footprints combine good growing practices with local supply chains.

Aya and Industry of All Nations are the winners, combining low-impact organic growing practices with local production. Aya does everything in Peru, and IOAN similarly does all growing and producing in one province in India.

Harvest and Mill, The Big Favorite, and Rawganique are not far behind. Heavier t-shirts mean more material, which creates small increases for what can be more durable products.

ISTO, is the most transparent in sharing its supply chain, including specific suppliers for each material and fabric they use. Unfortunately their international supply chain from India to Turkey to Portugal nearly doubles the impact of their materials. Though still a much better opinion than conventional options.

International shipping and distribution will skew footprints

The best way to ruin a good carbon footprint is through long distance shipping by air.

Drop shipping companies are notorious for this because instead of shipping via sea freight to the destination country, which has a tiny carbon footprint, they send each product by air direct to the buyer, which has the largest carbon footprint.

As consumers we can optimize this by buying from brands that distribute locally.. Aya for example distributes from Los Angeles. If you live in Europe, it’s likely better to buy from a brand that distributes in Europe, but has a slightly higher footprint, rather than shipping a lower footprint product internationally.

Arbor x Material Factors

Material Factors collaborated with Arbor to provide insights into the carbon emissions of these products, aiming to enhance the understanding of their environmental impact. Recognizing the significant carbon footprint of the fashion industry, this initiative focuses on the emissions throughout the t-shirts' production and transportation.

Measure the carbon impact of your products for free with Arbor’s platform.