The Silk Hour
Almost everything sold as a slip dress is polyester. Here is how to tell, and what to buy instead.
4 min read
The slip dress is the most convincingly counterfeited garment in fashion. The shape is right, the shine is close enough under shop lighting, the price feels like a find. Then you read the label and it says polyester, or it says satin, which is not a fiber at all. Satin is a weave. It describes how the threads cross each other, not what the threads are, and it is doing an enormous amount of quiet work in product descriptions.
You find out the difference about an hour into the evening. Silk absorbs moisture and moves heat away from the body, so it stays cool against warm skin and settles rather than sticking. Polyester does neither, which is why the same dress starts to cling, holds warmth in, and smells the next morning in a way silk does not. Researchers in Ghent found that odor-causing bacteria grow more readily on polyester than on natural fibers, which is the mechanism behind something most people have simply noticed.
Real silk is not always the expensive option, and it is never the one you have to guess at. Here is how to read the label, and the pieces that pass.
The slip, and how to tell it is real
One rule covers almost every case: the composition names the fiber, or the fiber is not there. A real silk dress says silk, usually with a percentage and sometimes with a weight in momme, the unit silk is measured by. An imitation says polyester, or nylon, or nothing at all beyond the word satin. If the product page is describing the feel rather than the fiber, that is the answer.
What you get for it is a garment that moves. Silk is a protein fiber with a long staple and a natural irregularity to it, so a bias-cut slip falls in a way a synthetic cannot copy: heavier at the hem, fluid across the body, catching light unevenly instead of in one flat sheet. Every dress below is 100% silk.
Washable silk changed the calculation
The old objection to silk was maintenance. Dry clean only, on a dress you wanted to wear on a warm night, was a real reason to buy the polyester instead. That objection has largely gone. Washable silk is the same protein fiber finished so it can take a cold gentle cycle, and a handful of houses have built their whole line around it.
This matters more than it sounds, because the argument for natural fiber falls apart if the garment is too precious to wear. A silk slip you can put through the machine gets worn twenty times a year instead of twice, and cost per wear stops being the reason to compromise. Check the care label rather than assuming either way, since plenty of silk is still dry clean only and the brands that have solved it say so plainly.
Silk that is not a dress
The slip gets the attention, but silk is at its most useful in the pieces you reach for without thinking about it. A silk tee under a blazer. A boyfriend shirt with the sleeves rolled. A skirt that moves. These are the items where the fiber earns its price across a year rather than across one night out.
They are also where the fake is hardest to spot, because a silky-feeling polyester tee looks fine on a hanger and only fails once it is warm. The tell is the same as always: read the composition, not the adjective. A silk-linen blend is worth knowing about too. Linen gives silk structure and silk gives linen fluidity, and at roughly half and half you get a cloth that does something neither fiber manages alone.
A note on what silk is and is not, because it attracts as much overclaiming as polyester attracts fear.
Silk is a natural protein fiber spun by silkworms. It is genuinely good at temperature regulation and moisture handling, and unlike polyester it is not a plastic and does not shed microplastic fibers in the wash. Those are properties of the fiber and they are not in dispute.
What silk is not is medicinal. You will find claims that silk pillowcases cure acne or that silk sheets fix your hair, and the evidence for those is thin to nonexistent. We are not going to repeat them. The honest version is narrower and still worth the money: silk is a breathable natural fiber that feels better against warm skin than plastic does, and it lasts if you look after it.
One more thing worth saying plainly. Satin is a weave, not a fiber, and it is the single most useful word in the business for selling polyester at a silk price. A satin-weave polyester and a satin-weave silk look similar in a photograph and are completely different garments. Toxome reads the composition rather than the product name, which in this category is most of the job.
Read the fiber, not the adjective. You can shop the silk edit, every piece scored by Toxome on its published composition, and know the slip you are buying is the real one.
Sources
- Toxome. Silk: the fiber guide.
- Toxome. Polyester: what the fiber is and how it scores.
- Callewaert, C. et al. (2014). Microbial odor profile of polyester and cotton clothes. Applied and Environmental Microbiology.
pins Toxome in your Google results, so our reporting shows up first when you search fabrics and brands.