Life & Style

Ethical Fashion, Life & Style

Best Ethical and Sustainable Thermals To Keep You Cosy

Looking for the best ethical and sustainable thermals to keep you cosy? Here are my top picks – from vegan-friendly bamboo to cosy ethically sourced merino wool and more.

To help support the running costs of Moral Fibres, this post contains affiliate links, denoted by *. We may earn a small commission, at no extra cost to readers, on items that have been purchased through those links.

I used to think thermals were just for mountaineers and skiers. And then quite some years ago my parents retired. Suddenly, their wardrobes expanded with a full array of thermals for almost every occasion. I thought they had taken up mountain climbing or some other kind of alpine pursuit. And then I realised, no. There were no alpine adventures. They were just looking for ways to keep the heating off for as long as possible, now that they were at home much more often.

My parents have always been the original energy savers. In fact, I feel like I’ve learned almost all that I know about saving energy from them. But I’ll be honest, I did giggle at them when they were decked out in all their thermals.

But life has now gone full circle, and in response to rising energy bills, I’ve found myself thinking that my parents have been on to something all these years. As such, I’ve found myself searching for sustainable thermals as a way to keep warm when working from home, without resorting to cranking up the heating.

So whether you are concerned about heating costs, and are looking for a way to stay cosy at home without turning on your heating so much. Or whether you are looking to get out on some alpine adventures without freezing your bits off, then here are the best ethical thermals I’ve found.

Ethical and Sustainable Thermals

No matter if you are vegan or you prefer natural fibres, I’ve sourced the most sustainable and ethical thermals. From performance wear to casual wear, there’s something for every circumstance.

To help you out, I’ve included a rough price range for each brand. The key to this guide is:

 £ = Under £50 | ££ = £50 – 100 | £££ = £100+

Finisterre Bamboo & Natural Fibre Thermals

Person wearing Finisterre's ethical and sustainable thermals

Budget: £ – ££

Caters for sizes: Men’s XS – XXL / Women’s 6 – 18

Whether you are looking for vegan-friendly bamboo baselayers, or you prefer natural fibres such as merino wool, then Finisterre* has you covered. Catering for both men and women, Finisterre has a huge range of sustainable thermals. From long johns to boxers, long-sleeved and short-sleeved layers to cosy roll necks, this is Finisterre’s speciality.

In terms of ethical credentials, Finisterre is the real deal. Since their inception in 2003, sustainability has been at the heart of everything they do. From their commitment to using plastic-free packaging to their commitment to using the most sustainable fabrics possible, Finistere has carefully considered all aspects of its business.

For example, they have always used non-mulesed wool for all of their Merino base layers and knitwear. Their Merino wool comes from traceable suppliers, for guaranteed non-mulesed sheep.

Finisterre will also help you to repair your Finisterre clothes, or they will repair them for you if you can’t. And when your clothes wear out, they offer a handy takeback scheme. Here they will either upcycle your old clothes into new products or fully recycle them. 

And in 2018, Finisterre became B Corp Certified. This means that Finisterre has been independently certified as a business that is committed to prioritising the environment and society in every aspect of its activities.

Shop Men’s Sustainable Thermals* and Women’s Ethical Thermals* directly at Finisterre.

Organic Basics Sustainable Tencel Thermals

Person wearing Organic Basics ethical long johns

Budget: £ – ££

Caters for sizes: XS – XXL

Organic Basics offer a range of men’s ethical long johns*, women’s leggings and baselayer tops for both men and women, all made from Tencel. This is an eco-friendly and vegan-friendly fabric, made from wood pulp, that is very durable and breathable, yet smoother than cotton and softer than silk.

Having tried it out, I would say Organic Basic’s collection is less on the technical side and more of an everyday sustainable thermal. Layer up in them for keeping cosy at home, or for keeping warm whilst out and about in the winter months, without feeling sweaty.

Again, sustainability has always been Organic Basic’s core mission. As such, every aspect of their operations is carefully considered. From plastic-free packaging to quality eco-friendly fabrics that are designed to last. Organic Basics also avoid making seasonal collections to minimise wastage – instead, focusing on timeless styles. Organic Basics also only partners with factories that care about their impact.

Use discount code WENDYOBC to take 10% off your order.

Joha Natural Fibre Thermals

Person wearing Joha's sustainable thermals

Budget: £

Caters for sizes XS – XXL

For cosy ethical thermal baselayers, then try Joha*, a Scandinavian brand that’s been going for over 50 years. When it comes to thermals, this brand knows its stuff – it only makes thermals, and makes them well. All of their products – from long johns to vests, boxers, and long sleeve tops, are made from mulesing-free merino wool and/or organic cotton – there are no synthetic fibres here.

What’s more, all of their products have Oeko-Tex Standard 100 certification. This means that every component – right down to the thread – has been tested for harmful substances.  For extra peace of mind, Joha also holds Scandinavian independent certification for the responsible sourcing of wool.

Shop women’s Joha thermals* and men’s Joha thermals* in the UK via Alpinetrek*.

BAM: Bamboo Thermals

Person wearing BAM's sustainable bamboo thermal base layers

Budget: £ – ££

Caters for sizes: men’s S – XXL / women’s 8 – 16

For vegan-friendly base layers, hot foot it to BAM*. With bamboo baselayers for both men and women – these soft and stretchy insulating base layers help to keep you warm on even the coldest days.

Designed for both performance and comfort, the flatlock stitching means these sustainable thermals are chafe-free.

Made from bamboo jersey blended with organic cotton, this sweat-wicking blend is designed to be just thick enough to keep you warm, yet highly breathable so you don’t overheat. The blend is also incredibly absorbent so it helps you to stay dry, helping you with your temperature control.

From long sleeve to short sleeve tops, and zip neck tops to help keep your neck cosy, to long johns for men, BAM has a great selection.

What’s more, BAM only works with responsible producers. For example, they only work with bamboo fibre producers who use safe and responsible chemistry and waste treatment practices, and who are committed to investing in the technology needed to further improve their practices, processes, and chemistry where necessary.

They also ensure that their suppliers are paying their staff above the national minimum wage and are offering good working conditions throughout the entire supply chain.

I wrote more about BAM and its ethical commitments – if you are interested in reading more.

Shop women’s base layers* and men’s base layers* at BAM.

As always, as I come across more thermals, I’ll be sure to add them here, so do check back again.

Looking for more ways to keep cosy? I have you covered. Try my guides to ethical jumpers, ethical hats, ethical gloves, and ethical socks.

Main image used c/o Finisterre

Ethical Fashion, Life & Style

What Is Tencel Fabric And Is It Ethical, Eco-Friendly or Sustainable?

Got questions about Tencel fabric? Here’s everything you need to know about this fabric, and whether Tencel is an eco-friendly, ethical or sustainable choice when it comes to clothing.

Browse any ethical clothing brand, and you will probably come across items of clothing made from a fabric called Tencel. Given its ubiquity across the ethical sphere, you may well be wondering what Tencel is. And what it is exactly that makes Tencel a prime choice for these eco-friendly and sustainable brands. Let’s take a look!

A Beginners Guide To Tencel Fabric

A picture of blue fabric, with a blue text box that says what is tencel, and what makes it a sustainable fabric?

Here is almost everything you could ever need to know about Tencel fabric. From what it is, to if it is an eco-friendly or sustainable choice, and more. You’ll be a Tencel expert in no time.

What Is Tencel Fabric Exactly?

First things first, let’s get to the basics. What is Tencel? Well, Tencel is the brand name for two types of fabric – Lyocell and modal – that are made by an Austrian company called Lenzing AG.

To help simplify this, if you are in the UK you probably refer to a vacuum cleaner as a Hoover or sticky tape as Sellotape. With Tencel, it’s the same thing – the fabric is simply referred to by the brand name. Both types of fabric are often referred to as Tencel, as they share very similar properties and production methods.

So What Is Lyocell?

So what is Lyocell then? Lyocell is a soft semi-synthetic fabric, known for its strength, its moisture absorption properties. This sounds good, but does it do good?

Well, unlike synthetic fibres that are made from plastic, Lyocell is made from wood pulp.  And in particular, Tencel Lyocell fabric is made from wood pulp sourced from sustainably managed forests certified by both the Forest Stewardship Council (FSC) and the Program for the Endorsement of Forest Certification Schemes (PEFC). 

The wood pulp used to manufacture Lyocell is most commonly derived from eucalyptus trees. This pulp is then processed with a special solvent. This solvent dissolves the pulp into a rather viscous liquid, similar to the consistency of honey.

Once liquified, the solution is then pumped through a thimble-shaped metal nozzle, called a spinneret. This nozzle has very fine holes in it, which means that the wood pulp solution then emerges from the spinneret as long fibres. These fibres are then spun into continuous strands, ready for use in the fabric industry.

Whilst Lyocell is made by different brands, Tencel Lyocell in particular is produced in a highly regulated closed-loop process. What this means is that the solvents and water used to create Tencel are recovered, and reused again.

In fact, according to Lenzing AG, when making Tencel Lyocell the water is 100% recovered and recycled. Meanwhile, the solvent is almost all fully recovered and reused – with a recovery rate of more than 99.5%. All in all, Lenzing AG say that 50% fewer greenhouse gases are emitted throughout the manufacturing process when compared to generic Lyocell. 

And What Is Modal?

We’ve covered Lyocell, so what about modal? Modal is a soft semi-synthetic fibre that feels like silk when worn. In fact, it’s often used as an ethical alternative to silk.

Modal is produced in a similar manner to Lyocell. However, instead of eucalyptus, modal is predominantly made from the pulp of beech trees. This creates an even softer fabric prized by the fashion industry.

Again, whilst modal is made by many brands, what makes Tencel’s modal more sustainable, is that their beech again only comes from sustainably managed forests. In addition, their modal is produced in that similar closed-loop system. Here up to 95% of their production materials are recovered and reused.

Compared to silk, modal is much more hard-wearing and more ethical. It also keeps its shape and finish, even when subject to frequent laundering. Meanwhile, unlike garments made from 100% synthetic fibres, such as polyester, modal allows the skin to breathe and does not trap sweat or odours.

What’s The Difference Between Tencel and Viscose or Rayon?

image of scissors, measuring tape and thread on fabric

Like Tencel fabric, viscose and rayon are derived from wood pulp. However, the big difference is that producing viscose and rayon is a much more energy-intensive process.

Making rayon and viscose is also a far more chemically intensive production process. It involves using a potentially harmful chemical called sodium hydroxide. This can be harmful to workers. Sodium hydroxide is commonly found in drain cleaners and oven cleaners, and we know how harmful these products can be.

The other big problem with sodium hydroxide is that it is not easily recoverable. This means that rayon and viscose cannot be produced in a closed-loop system. If not regulated properly, this can give rise to some very serious water pollution problems. It can also pose a severe threat to people and the environment around production sites.

Tencel, on the other hand, is made without sodium hydroxide. Instead, this chemical is replaced with an organic compound called N Methylmorpholine N-oxide (NMMO). NMMO is much more easily recoverable. This allows it to be used again and again to produce more Tencel, without giving rise to water pollution problems.

What Is Better, Cotton or Tencel?

Now that we know that Tencel is a better choice than synthetic fabrics, or other semi-synthetic fabrics, such as viscose or rayon, you might be wondering about how it compares to natural fibres. And specifically, you might be wondering which is better – cotton or Tencel?

It is difficult to compare two very different fabrics. What I would say is that Tencel tends to be softer and more durable than cotton. It drapes well and doesn’t wrinkle easily, so isn’t as high maintenance as cotton. Essentially, you could ditch your iron and no one would know.

Meanwhile cotton is a much crisper fabric with a more rigid shape. If you’re a fan of starched shirts, crisp lines, and freshly pressed clothing, then cotton is the choice for you. However, I would always say that organic cotton is always a better choice than regular cotton or BCI cotton.

Of course, there is a way to get the best of both worlds. Tencel often gets blended with other fibres, such as cotton, to help give the finished article Tencel-like properties. For example, Tencel may get blended with denim to increase its softness.

Is Tencel Fabric Eco-Friendly?

As Tencel fabric is semi-synthetic then there are definite pros and cons. I would say that Tencel Lyocell and modal are eco-friendlier choices, compared to synthetic fabrics made from fossil fuels. These include fabrics such as polyester or nylon.

Other semi-synthetic fibres such as rayon or viscose can be hazardous to the environment. We’ve already looked at the chemical processing problems there. However, chemical processing aside, there are also no guarantees that the wood pulp used by rayon producers comes from sustainably managed forests. In fact, the rayon and viscose industry has been attributed to rainforest destruction in Indonesia.

What’s to like about Tencel, is that there are guarantees that the wood comes from sustainably managed forests. This makes Tencel a more eco-friendly choice, compared to its other semi-synthetic cousins.

What About When Compared to Natural Fabrics?

When it comes to natural fibres, the picture is a little more opaque.

Whilst the myth that cotton is a water-intensive crop to grow has recently been debunked, there are still gaps in our knowledge about cotton. In particular, there is a huge knowledge gap when it comes to the use of pesticides in the conventional cotton industry.

What we do know is that, unlike cotton, trees can be grown without the use of pesticides, or minimal amounts of pesticides.

Eucalyptus trees – the key element in Lyocell – are incredibly hardy. They can grow on almost any type of soil. This means they don’t have to take up space on fertile agricultural land that could otherwise be used to grow food. Eucalyptus also grows incredibly quickly, without the need for pesticides or irrigation.

Likewise, beech – the key element in modal – is also a hardy species. It does not require artificial irrigation to grow. In fact, it uses about 10 to 20 times less water, compared to other fabric crops.

These tree species can be much less resource-intensive to grow. And as the wood pulp for Tencel fabrics is derived from sustainably managed forests, I would say that Tencel fabrics can be classed as more sustainable than conventionally grown cotton.

Let’s not get too carried away though. As Tencel does have to be chemically processed, I’d say it is probably less sustainable than gold standard eco-friendly fabrics. These include fibres such as organic cotton, recycled cotton, linen or hemp.

Is Tencel Biodegradable Or Compostable?

Tencel is both biodegradable and compostable. But wait up. Don’t go chucking your old clothes in your compost bin just yet. Tencel fibres are sometimes blended with other fibres. These additional fibres may not be biodegradable or compostable. If in doubt first carefully check the composition label.

Labels aside, there are other issues when it comes to composting clothes. Many items of clothing that are technically compostable shouldn’t be composted. Even items made from all-natural fabrics such as cotton, linen or hemp. This is because any dyes or finishes used on the fabric may not be so environmentally friendly. Nor may they contribute to good soil health.

What I would say is that it is energy and resource-intensive to make clothing. Composting fabric should always be the very final stage of a fabric’s lifespan. If your item is beyond the re-wear stage, it is always more sustainable to find ways to reuse or recycle the fabric, rather than compost it.

Is Tencel Fabric Breathable?

As Tencel is made from wood-based fibres, rather than plastic, then it is a very breathable fibre. This makes it especially suitable for all sorts of applications. In particular, look out for bed linen, shoes, underwear, gym wear, and summer clothing, if you are looking to get the full benefit from Tencel.

Where Can I Buy Tencel Products?

Fabrics made from Tencel can be found in all areas of the market. From underwear to dresses, jeans to shoes, bed linen, and more. Tencel pops up everywhere. Who knows, if you’ve shopped with an ethical retailer in the past, then you may be wearing something made of Tencel right now!

Here are some brands that use Tencel in their products:


Allbirds trainers in grey

Whilst Allbirds* are well-known for their wool-based shoes, they have branched out into Tencel. In fact, any of their shoes with a tree-based prefix is made from Tencel.

Camper Shoes

Camper shoes

Shoe brand Camper has a range of Tencel-based shoes* for men, women, and children. The fabric of these Courb trainers, for example, is made from 70% Tencel Lyocell fabric.

Organic Basics

Organic basics underwear

Organic Basics offer a wide range of women’s underwear and clothing made from Tencel fabric. From bras and knickers to tops, tees, and trousers, their Tencel collection* is wide-ranging.


Patagonia tencel top

Ethical clothing brand Patagonia offers a range of Fairtrade certified clothing products that are made from Tencel*. From soft and breathable men’s boxer shorts to women’s airy summer dresses and jumpsuits, Patagonia offers a wide range of clothing made from Tencel fabric.

People Tree

people tree tencel collection

People Tree’s Tencel collection* features beautifully drapey ethical dresses, tops, shirts, and skirts.


Urbanara tencel bedding

Urbanara’s Tencel bedding range* sees Tencel blended with linen, to create an incredibly soft fabric. On summer nights this will help to keep you cool in bed due to its moisture absorption properties.

In Short

Tencel’s production process has some great sustainability features. From the tracing of trees to sustainably-harvested forests. Right through to the fact that the process recycles water and chemicals. This makes Tencel fabric a much more sustainable choice, compared to synthetic fibres such as polyester and nylon. And it’s also a more sustainable choice than other semi-synthetic fibres such as rayon and viscose.

If you are buying a new product, then I would say that Tencel fabric is a sustainable choice to look for. Tencel looks good, feels good, and through its use of sustainable practices, does good.

However, be wary of claims of compostability. Instead, try to find ways to wear your item for as long as possible. From repairing, to recycling, reusing and repurposing, there are heaps of ways to keep your Tencel fabric out of the composter.