Why a 100% Cotton Hoodie Has Stretch in the Cuffs

You buy a hoodie labelled 100% cotton. You pull the cuff over your hand and it snaps back like a sock. Cotton doesn't usually do that, so the obvious question is whether the label is wrong.

Usually it isn't. In Canada the fibre content on a garment is allowed to leave out certain parts, and cuffs, hems and neck bands are on that list. The rib can carry a few percent of spandex while the body really is all cotton, and the label can still say 100% cotton. Here's what the rules say and what it means for wear and washing.

What the Canadian rules say about cuffs and waistbands

Fibre labelling in Canada falls under the Textile Labelling Act and the Textile Labelling and Advertising Regulations, enforced by the Competition Bureau. The regulations have a category called findings. Section 25 defines findings as textile parts added for a functional purpose, which differ in fibre content from the article they're added to, and which aren't part of the outer surface unless they sit at or along an edge.

The definition then gives examples, and they read like a description of a hoodie's trims: "leg, neck and wrist bands, waist bands, plackets and concealed pockets", plus "elastic material inserted in or added to the consumer textile article, including elastic waist bands, elastic leg bands, elastic wrist bands". Thread, zips and buttons are findings too.

Section 39 says that where an article contains findings, its fibre content "shall be shown exclusive of the findings". The fibre content of the findings may be shown, but only separately and after everything else. The Competition Bureau's Guide to the Textile Labelling and Advertising Regulations puts it more bluntly: "Findings do not have to be declared."

So if the cuffs and hem are knitted from a different yarn mix than the body, the label is expected to describe the body. A hoodie with a 100% cotton body and cotton-spandex rib can carry a label that reads 100% cotton, and that's the rule working as written, not a loophole somebody found.

The other route: "exclusive of elastic"

There's a second provision that matters when the stretch yarn is knitted into the fabric itself rather than added as a separate band. Section 31(d) says that where an elastic yarn makes up less than 5% by mass of the article or part, the fibre content may be shown without it, provided the other percentages are scaled up to total 100% and the words "exclusive of elastic" appear right after them.

The Competition Bureau guide gives a worked example for a wool fabric with 2% spandex. Any of these three is acceptable:

98% wool, 2% spandex
98% wool, 2% other fibre
100% wool exclusive of elastic

At 5% or more, the guide says the elastic yarn "must be disclosed as an integral part of the fabric". Section 29(2) also allows "all" or "pure" in place of 100% on the same basis, as long as the exclusion is shown properly.

On the name: section 26(1)(r) says a synthetic polymer that is at least 85% segmented polyurethane may be called spandex or elastane. Same fibre, two accepted words.

Why the rib gets the stretch and the body doesn't

A cuff and a waistband have a different job from the body. The body hangs. The cuff has to stretch over a hand, close back round a wrist, and do it over and over. Rib knit already helps here, because the alternating face and back stitches pull the fabric in across its width. A ribbed cuff in plain cotton stretches well. The trouble is coming back.

Cotton is not an elastic fibre. Stretch it and hold it and some of that stretch stays. Spandex is an elastomer. A paper in the Journal of Textile and Apparel, Technology and Management, Senthilkumar, Sounderraj and Anbumani (2012), describes how stretch knits are normally made by plating spandex alongside a companion yarn on a circular knitting machine, and notes that spandex gives more stretch and dimensional recovery than cotton yarn can on its own.

That study tested cotton-spandex single jersey, not rib, so it isn't a direct measurement of hoodie cuffs. The authors measured recovery using a method they cite as ASTM D4964-96, stretching samples for 10 cycles at extensions from 20% to 50%. The broad point carries over: the spandex is there for recovery, the part cotton is bad at.

If you've read our piece on whether you can unshrink a cotton hoodie, this is the same fibre behaviour from the other side. Cotton holds the shape you put it in, whether that's shrunk or stretched.

Is a cotton-spandex rib a bad sign?

Not by itself. It's a trade-off, and both sides have a case.

A rib with a few percent spandex usually holds its grip at the wrist and hem for longer. It also means the garment isn't a single fibre any more, and it adds a fibre that reacts to some things cotton shrugs off.

An all-cotton rib can be made to work. A heavier rib, a tighter knit and a well-judged cuff length all help it hold. It will relax more over time than a rib with spandex, and the usual result is a cuff that stays slightly open. Neither choice is the cheap one by default. The folklore that spandex is there to hide poor cotton isn't something we've seen tested anywhere, and we wouldn't repeat it.

What would settle it is a long-term wear study comparing all-cotton and cotton-spandex rib through repeated home laundering. We haven't found one in the published literature.

How to tell what's in the rib

The label won't always tell you, since findings don't have to be declared. A few practical checks:

Read the whole label, both sides. Some makers voluntarily list the rib separately, often as "Rib" or "Trim" after the main fibre content.
Look for "exclusive of elastic". That tells you there's elastic yarn under 5% in the part being described.
Stretch the cuff to roughly double and let go. A spandex rib snaps straight back. All-cotton rib returns more slowly and may sit a little wider.
Ask the seller. It's a fair question and the answer should be one line. That goes for us too.

What it changes about washing

Mostly nothing. Wash the hoodie the way the care label says, and our care instructions cover the heavy pieces specifically. Two things are worth a little extra caution once you know there may be spandex at the edges.

Chlorine bleach. The JTATM paper notes that chlorine bleaches have to be avoided when processing spandex fabrics because they may cause yellowing in spandex fibres, and that hydrogen peroxide is used instead. That was written about mill processing, not home laundry, and we haven't found a home-wash study on it. But it's a good reason to keep chlorine bleach off a rib you suspect has spandex. If something has already gone wrong with bleach, our post on fixing a bleach spot on a black hoodie covers what can and can't be done.

Heat. The same study found that heat setting and bleaching during manufacture both lowered how well the fabric recovered from stretch. That was controlled factory heat applied to make the fabric, not a tumble dryer. Nothing we've read measures what a home dryer does to a cuff over a few years. Low heat or air drying is the cautious choice, and it's kinder to heavy cotton anyway.

The short version

A hoodie can say 100% cotton and still have stretch in the cuffs, and in Canada that's normally lawful. Neck, wrist and waist bands count as findings, and the fibre content is shown without them. Elastic yarn under 5% can also be left out if the label says "exclusive of elastic". The spandex is there for recovery, which cotton doesn't do well. Whether it's better than an all-cotton rib depends on what you value, and the long-term evidence either way is thinner than the confident answers online suggest.

Sources

Government of Canada, Justice Laws Website. Textile Labelling and Advertising Regulations, C.R.C., c. 1551, sections 25, 26(1)(r), 29(2), 31(d) and 39. Last amended 2019, consolidated text current to 21 September 2026. laws-lois.justice.gc.ca
Competition Bureau Canada. Guide to the Textile Labelling and Advertising Regulations. Published 2000, page modified 19 January 2022. competition-bureau.canada.ca
Senthilkumar, M., Sounderraj, S. and Anbumani, N. Effect of Spandex Input Tension, Spandex Linear Density and Cotton Yarn Loop Length on Dynamic Elastic Behavior of Cotton/Spandex Knitted Fabrics. Journal of Textile and Apparel, Technology and Management, Volume 7, Issue 4, 2012. jtatm.textiles.ncsu.edu