Fabric guide: natural vs synthetic fibers and US care label symbols

The fiber content and the care label are the two most useful pieces of information sewn into any garment. Together they tell you how a piece will feel, how it will age and how much effort it will take to keep it looking good. This guide covers both.

The big picture: what the world’s clothes are made of

According to Textile Exchange’s Materials Market Report 2024, global fiber production reached 124 million tonnes (metric tons) in 2023, up from 116 million tonnes in 2022. Polyester alone accounted for 57% of that total. Manmade cellulosic fibers, such as viscose, made up about 6%, and fibers recycled from pre- and post-consumer textiles were under 1%. Cotton production was about 24.4 million tonnes. In other words, if you pick up a random garment, the odds favor polyester.

Natural fibers

Natural fibers come from plants or animals. Wikipedia’s overview groups them as follows:

Plant fibers: cotton is a seed fiber; flax (the source of linen), hemp and jute are bast fibers, taken from the stems of plants.
Animal fibers: wool, silk, camel hair and angora are protein-based; wool is made of keratin and silk of fibroin.

As a group, natural fibers are renewable and biodegradable, tend to break down faster than synthetics, absorb water well and are generally less stiff and strong than synthetic fibers. Their behavior also changes with moisture.

Synthetic fibers

Synthetic fibers are made from polymers. Wikipedia’s article lists the main ones and their history:

Fiber	Origin	Notes from the source
Nylon	Developed at DuPont by Wallace Carothers’ team; nylon 66 first synthesized in 1935	Replaced silk in stockings; also used for parachutes and ropes
Polyester	Patented in Britain in 1928; Terylene produced in 1941 by Whinfield and Dickson	About 60% of synthetic fiber production
Acrylic	Listed from 1950	Soft, but with a shorter garment lifespan
Spandex	Listed from 1959	Listed among specialty fibers

The same article notes two environmental drawbacks: synthetic fibers are not biodegradable and may take 200 years or more to decompose, and a single wash of synthetic garments can release up to 700,000 microfibers, many of which reach marine environments.

Natural vs synthetic at a glance

Summarized from the Wikipedia articles on natural and synthetic fibers.
	Natural (cotton, linen, wool, silk)	Synthetic (polyester, nylon, acrylic)
Source	Plants and animals	Polymers, mostly fossil-based
Water	Absorbs well	Not covered as a group by the source; check the specific fiber
Strength	Generally lower	Generally higher
End of life	Biodegradable	Not biodegradable; sheds microfibers

Blends combine the two, for example cotton with a little spandex for stretch. Checking the percentages on the fiber label tells you which behavior will dominate.

The care label: what US law requires

In the United States, the Federal Trade Commission enforces the Care Labeling Rule. According to the FTC’s business guide, manufacturers and importers of textile clothing must attach a permanent label, visible at the point of sale and legible for the garment’s useful life, that gives complete regular care instructions, or a warning if the item cannot be cleaned without harm. Washing instructions must say whether to machine or hand wash and, where needed, the water temperature, and must cover bleaching, drying and ironing. Makers must have a reasonable basis, meaning reliable evidence, for every instruction. Shoes, gloves and hats are among the exemptions.

Symbols are optional when the instructions are written out. The FTC accepts the symbols in ASTM standard D5489; ASTM describes the standard as a uniform system of care symbols intended to reduce reliance on language-dependent instructions, and lists D5489-25 as its current version.

Reading the five symbol families

Every care symbol belongs to one of five families. A cross through any symbol means “do not”.

Symbol meanings summarized from Wikipedia’s article on laundry symbols. Drawings are simplified.
Symbol	Family	How to read it
	Washtub — washing	Dots show maximum temperature; in the North American system 1–4 dots mean 30, 40, 50 and 60 °C (about 86, 104, 122 and 140 °F). One bar beneath means reduced agitation (a synthetics-type cycle), two bars very minimal agitation (as for wool and silk). A hand in the tub means hand wash.
	Triangle — bleaching	Empty: any bleach. With diagonal lines: non-chlorine bleach only. Crossed: no bleach.
	Square — drying	A circle in the square means tumble dry; one dot is low heat, two dots normal heat. Other marks inside a square cover line, flat and drip drying.
	Iron — ironing	One dot about 110 °C (230 °F), two dots about 150 °C (302 °F), three dots about 200 °C (392 °F).
	Circle — professional care	Dry cleaning or professional wet cleaning (W). Letters inside tell the cleaner which solvent to use; bars beneath mean a gentler process.

International labels use the same five shapes but often print the wash temperature as a number inside the tub rather than as dots, so clothes bought abroad may look slightly different.

Practical takeaways

Read the fiber percentages before you buy; they predict feel, warmth and wear.
Follow the care label: under the FTC rule, the maker must have a reasonable basis for what it says.
Washing synthetics less often, and at lower temperatures where the label allows, also means fewer washes in which microfibers can shed.

Fibers, fabrics and the care label