Why Does Silk Smell? What's Normal and What Isn't

Silk starts as a caterpillar's thread, and about a quarter of its raw weight is gum. Sometimes, when you open a new package, your nose is the first to find out.

Why does new silk smell?

The usual explanation is leftover sericin, the protein that binds silk filaments together in the cocoon. A process called degumming washes most of it away, but traces can remain, more in some silks than others, and a sealed package keeps whatever scent there is close. The chemistry of sericin is well documented. Its link to the smell rests mostly on the experience of people who work with silk, because we found little lab research on odor. Dyes and finishes may add a note of their own.

What smells are normal on silk?

A faint natural smell that fades is normal. Anything musty, sour or sharply chemical is worth acting on.

What you smell	Likely cause	What to do
Faint and natural, sometimes slightly fishy, on new silk	Traces of silk protein	Air it, and wash it if it lingers
Musty, like a basement	Mold or mildew, or silk put away damp	Look for spots and see how to remove mold from silk
Sour, or like your hair products	Sweat, oils or buildup	Wash it, and a little sooner next time
Sharp or chemical, still there after two washes	Finishes or dye residue, or the fabric may not be what the label says	Contact the seller

A smell can't tell you what's in a fabric. LS Silk pillowcases are made from silk certified to OEKO-TEX® STANDARD 100, which means the material was tested for harmful substances. That speaks to the chemistry, and it says nothing about scent.

How do you get the smell out of new silk?

Give it air first, then water. Hang it somewhere with moving air, out of direct sun, for a few days. If you can still smell it, hand wash it cold, or machine wash it on a gentle cycle in a mesh bag with mild detergent, then hang it or lay it flat to dry. Do not bleach it or tumble dry it.

Fiber artists who handle raw silk report that repeated washing wears the smell down, and that some pieces take longer than others. Skip the room spray: Ohio State University Extension warns that alcohol-based products such as perfume can damage silk.

Can a smell tell you if silk is real?

Not until you burn it. Unburned silk has no smell that proves anything, and plenty of real silk has no noticeable smell at all. A burning thread of silk smells like singed hair, because both are protein. Our guide to how to tell if silk is real covers that test and some simpler ones.

See LS Silk pillowcases: 100% mulberry silk on both sides →

A few days on a hanger and that first whiff of cocoon is usually gone, which leaves you with the part of the caterpillar's work you came for.

Frequently asked questions

How long does the smell of new silk last?

Often only a few days of airing. If it's still there, a gentle wash or two usually helps, although some silks take longer. There's no fixed timeline, because it depends on how much residue the silk carries.

Why does my silk smell bad after washing?

Usually it stayed damp too long, or detergent wasn't fully rinsed out. Wash it again in cold water with a small amount of mild detergent, rinse it well, then hang it or lay it flat where air can move. If it smells musty, check for mold.

Is the smell on new silk harmful?

A faint natural smell that fades isn't usually a sign of a problem. A strong chemical smell that stays is a reason to contact the seller. If a fabric smell gives you headaches or trouble breathing, stop using it and talk to your doctor.

Does real silk always have a smell?

No. Many silk pieces have little or no noticeable smell, particularly after a wash. Having no smell doesn't make silk fake, and having one doesn't prove it's real.

Related reading: What Is Silk and Where Does It Come From? · How to Store Silk and Prevent Moths · What Does OEKO-TEX Certified Silk Mean?