Bras and underwear are rarely made from one material alone. A single garment may combine a cotton lining, polyamide lace, polyester thread, elastane in the stretch areas, foam padding, metal hardware and decorative trims.
Understanding the words on the composition label is useful, but those words do not all describe the same type of thing. Cotton, silk, polyamide, polyester and elastane are fibre names. Microfibre describes exceptionally fine fibres rather than one particular fibre chemistry. Lace and satin describe textile structures or fabric types and can be produced from several different fibres.
The material name is therefore only the beginning of the care decision. The complete garment, its construction and its care label must still be considered.
Fibres, fabrics and garment structures are different things
A fibre is the basic textile material from which yarns are made. Fibres may be natural, such as cotton and silk, or manufactured, such as polyamide, polyester and elastane.
Yarns are then knitted, woven, looped, embroidered or otherwise constructed into fabrics. The way the yarns are arranged affects the surface, stretch, weight, strength and appearance of the resulting textile.
The complete garment introduces another layer of complexity. A bra or pair of underwear may include:
- several textile fibres;
- knitted, woven or lace sections;
- elastic bands;
- foam or other padding;
- bonded seams;
- underwires;
- hooks and eyes;
- printed or dyed surfaces;
- embroidery, bows and other decorations.
European textile labelling rules treat cotton, silk, polyamide, polyester and elastane as defined fibre names used to describe fibre composition. Lace, satin and microfibre do not provide the same kind of compositional information.¹
Cotton
Cotton is a natural cellulosic fibre obtained from the cotton plant. It is widely used in underwear because it can provide a soft surface and absorb moisture.
Cotton fibres have relatively low natural elastic recovery compared with stretch fibres. For that reason, close-fitting cotton underwear frequently contains elastane or uses a knitted construction to improve fit and movement.
Cotton may appear in different parts of a garment:
- as the main fabric in everyday briefs;
- as a gusset lining;
- in bra linings;
- in lace or decorative elements;
- as part of a cotton-rich blend.
Cotton is absorbent and becomes stronger when wet, but the word cotton does not establish the safe washing temperature of the complete garment.² A cotton garment may also contain:
- an elastane waistband;
- polyamide lace;
- heat-sensitive prints;
- elastic thread;
- bonded components;
- foam padding.
A label that says cotton therefore does not automatically mean that the garment can be boiled, washed at 60°C or washed at 90°C.
The complete washing method is covered separately in How to wash cotton underwear.
Silk
Silk is a natural protein fibre. The filament is produced by silkworms when forming their cocoons and can be used to create lightweight fabrics with a naturally smooth appearance and sheen.
Silk can be used for:
- bra cups;
- briefs;
- camisoles;
- slips;
- linings;
- lace;
- satin fabrics;
- decorative trims.
The word silk identifies the fibre, but it does not identify one standard fabric construction. Silk yarn can be woven or knitted into textiles with different weights, finishes, colours and levels of stability.
A silk garment may also contain elastane, polyamide lace, elastic bands, padding or bonded sections. Its dyes and finishes may introduce additional care limits.
Because silk is a protein fibre, its response to detergents and chemical conditions differs from that of cotton and many synthetic fibres. Strongly acidic or alkaline treatment can affect the protein structure.³ Friction, uncontrolled heat and rough handling may also be unsuitable for delicate silk constructions.
This does not mean that every silk garment follows the same instructions or that all silk must automatically be hand-washed. The individual care label remains the deciding boundary.
A complete material-specific process is covered in How to wash silk lingerie.
Polyamide
Polyamide is a family of manufactured synthetic fibres. Nylon is a commonly recognised name within this family, and European composition labels may use the wording polyamide or nylon.
Polyamide is frequently used in bras and underwear because it can be made into fine, lightweight yarns and smooth fabrics. It may appear in:
- ace;
- mesh;
- microfibre fabrics;
- bra linings;
- cup coverings;
- seamless underwear;
- straps and wings;
- decorative details.
Polyamide itself does not necessarily make a garment stretchy. Stretch may come from:
- elastane blended into the fabric;
- the knitted construction;
- elastic bands;
- a combination of these elements.
A garment containing a high percentage of polyamide may still have its care boundary determined by a smaller percentage of elastane, by foam cups, by glued seams or by delicate lace construction.
Polyamide should not be treated as another word for polyester. They are separate fibre families and may behave differently during manufacturing, wearing and care.
Polyester
Polyester is another family of manufactured synthetic fibres. Like polyamide, it can be produced as fine filaments and used to create lightweight, smooth or structured fabrics.
In bras and underwear, polyester may be found in:
- mesh;
- satin;
- embroidery;
- sewing thread;
- cup linings;
- padding covers;
- sports-bra fabrics;
- printed or decorative sections.
Polyester can sometimes resemble polyamide by sight and touch. A smooth synthetic fabric cannot therefore be reliably identified by appearance alone.
The composition label should be checked instead of assuming that every smooth synthetic fabric is polyamide, polyester or a fixed blend of the two.
Polyester also does not automatically establish one washing method. The garment may include elastane, lace, foam, bonded sections, underwires or finishes that require a milder programme than the main polyester fabric might otherwise tolerate.
Elastane
Elastane is a manufactured stretch fibre designed to extend and recover towards its original length. In North American terminology, the generic name spandex is also commonly used.
Elastane may form only a small percentage of the composition label, but it can perform a major structural role. It helps close-fitting garments:
- stretch during dressing;
- follow body movement;
- remain close to the skin;
- recover after being extended;
- maintain support and fit.
It may be present in:
- waistbands;
- leg openings;
- bra wings;
- underbands;
- straps;
- stretch lace;
- seamless fabrics;
- sports bras;
- shapewear.
The highest percentage on the label is not always the most important part for care. A brief labelled predominantly cotton or polyamide may depend on a much smaller amount of elastane for its functional fit.
Heat, strong chemical treatment, excessive mechanical action and unsuitable drying can affect elastic components over repeated care cycles.
The relevant questions are:
What is the main fibre?
Which material provides the garment’s stretch, recovery or support?
The material-specific risks are explained in How to protect elastane and stretch fibres in lingerie.
Microfibre
Microfibre does not identify one specific polymer in the way that cotton, silk, polyamide, polyester and elastane do.
The term describes fibres of very small dimensions. Technical textile standards define microfibres by their fineness or diameter rather than by whether they are natural or synthetic.⁴ In lingerie retail language, microfibre usually refers to a fine, smooth fabric commonly made from:
- polyamide;
- polyester;
- combinations of polyamide and polyester;
- a blend containing elastane for stretch.
Two garments described as microfibre may therefore have different fibre compositions and different care instructions.
Microfibre also does not tell the user:
- whether the fabric is knitted or woven;
- whether elastane is present;
- whether the garment contains bonded seams;
- whether it has foam padding;
- which wash temperature is permitted;
- whether tumble drying is allowed.
Treat microfibre as a description of fineness and fabric character, not as a complete fibre-composition or care instruction.
Lace
Lace is a family of decorative openwork textile structures and techniques. It is not one fibre.
Lace used in modern bras and underwear may be made from:
- polyamide;
- polyester;
- cotton;
- silk;
- viscose;
- elastane blends;
- combinations of several fibres.
It may also be:
- rigid or stretchable;
- knitted, embroidered or otherwise constructed;
- used as a complete fabric;
- applied as a trim;
- attached to mesh or another supporting fabric;
- decorated with additional threads or finishes.
Stretch lace often contains elastane, but not every lace fabric stretches. Similarly, cotton lace and polyamide lace may share a similar visual pattern while having different fibre compositions and care boundaries.
The open construction of lace can also make the complete textile vulnerable to snagging, pulling or distortion, irrespective of whether the fibre itself is considered durable.
The correct washing method must therefore consider:
- the fibre composition;
- the lace construction;
- the fineness of the yarn;
- whether the lace stretches;
- attached embroidery or trims;
- the rest of the garment;
- the care label.
A complete lace-specific process is covered in How to wash lace lingerie.
Satin
Satin is not another word for silk.
Satin describes a weave structure that uses relatively long yarn floats to create a smooth, often lustrous surface with a distinct face and reverse.⁵ Satin can be made from:
- silk;
- polyester;
- polyamide;
- acetate;
- viscose;
- other fibres or blends.
A garment described as silk satin is made with silk fibre using a satin structure. A polyester satin uses polyester. Both may appear smooth and lustrous, but they are not the same material.
The word satin alone does not reveal:
- the actual fibre composition;
- whether elastane is present;
- whether the surface is printed or finished;
- whether the garment is washable;
- which detergent or temperature is suitable.
The longer surface floats that help create satin’s smooth appearance also mean that the fabric structure should be considered when assessing friction and snagging. Care should not be selected from shine or softness alone.
One garment may combine several material categories
A single bra might include:
- polyamide lace on the outer cup;
- polyester lining or sewing thread;
- elastane in the wings and underband;
- foam inside a moulded cup;
- cotton in a small lining section;
- a satin bow at the centre;
- metal underwires and hooks.
A pair of underwear might combine:
- a cotton gusset;
- a polyamide body fabric;
- elastane for stretch;
- polyester embroidery;
- lace around the leg openings.
This is why one visible or prominent material cannot describe the complete garment.
A product name may highlight the main fabric or the feature considered most commercially relevant. For example:
cotton underwear
This does not necessarily mean that every component is cotton.
The same limitation applies to names such as:
silk bra
lace briefs
satin lingerie
microfibre underwear
These names cannot replace the actual fibre-composition and care labels.
The composition label and care label answer different questions
The fibre-composition label answers:
Which textile fibres are present, and in what proportions?
The care label answers:
Which washing, bleaching, drying, ironing and professional-care treatments can the complete garment safely tolerate?
These are related questions, but they are not interchangeable.
GINETEX states that the maximum washing temperature must be selected from the care label rather than from the fibre content alone. The care symbols refer to the most sensitive part of the complete article, including its colouring, finishes, accessories and applications.⁶
For help interpreting the individual symbols, see What do the symbols on lingerie care labels mean?
Why the largest percentage does not decide the wash
Suppose a garment contains:
- a high percentage of cotton or polyamide;
- a smaller percentage of elastane;
- elastic bands;
- lace;
- prints;
- bonded seams.
The main fibre may account for most of the garment’s weight, but a smaller component may determine whether the garment can withstand:
- higher temperatures;
- strong mechanical action;
- bleaching agents;
- intensive spinning;
- tumble drying.
A composition of 90% cotton and 10% elastane is not equivalent to a garment made entirely from cotton. The elastane may be essential to the fit, while additional elastic thread, dyes or trims may introduce further limits.
The washing method should protect the complete product, not only the material with the highest percentage.
Common material-label mistakes
Assuming that cotton means high-temperature washable
Cotton fibre may tolerate treatments that the complete garment cannot. Elastic waistbands, lace, prints, colour, seams and decorations may become the actual limiting factors.
Assuming that satin means silk
Satin is a structure, not a fibre. Polyester satin and silk satin may look similar while requiring different handling.
Assuming that lace identifies the composition
Lace can be made from natural, manufactured or blended fibres. The word lace does not determine the detergent, temperature or programme.
Treating microfibre as one material
Microfibre describes fibre fineness. The actual composition may be polyamide, polyester or a blend, sometimes with elastane.
Ignoring a small percentage of elastane
A low percentage does not mean elastane is unimportant. It may provide the garment’s stretch, recovery and fit.
Reading only the first material listed
The largest component does not necessarily determine the safest care method. Smaller components and non-textile structures may impose stricter limits.
Identifying synthetic fabrics by touch
Polyamide, polyester and blends can be produced in many weights, textures and finishes. Appearance and softness are not reliable substitutes for the label.
Selecting care from the material name alone
The same fibre can be used in a stable everyday fabric, fine lace, satin, mesh or a bonded structure. Fibre composition and textile construction must be considered together.
A practical way to read a lingerie material label
When examining a bra or pair of underwear:
- Find the fibre-composition label.
Identify all listed fibres and their percentages. - Separate fibre names from fabric descriptions.
Cotton, silk, polyamide, polyester and elastane are fibre names. Lace, satin and microfibre provide different kinds of information. - Look beyond the largest percentage.
Note smaller amounts of elastane and any other component that may affect stretch, fit or heat tolerance. - Inspect the complete construction.
Check for lace, mesh, elastic bands, foam, moulded cups, bonded seams, underwires, prints and decorations. - Read the care label separately.
Do not calculate a washing temperature from the composition percentages. - Choose a process compatible with every important component.
Temperature, mechanical action, detergent, spinning and drying must suit the complete garment. - Use the material-specific guidance where needed.
Silk, lace, cotton and elastane each have separate care questions that cannot be fully answered by the composition label alone.
The most useful rule
A material name describes only one part of a bra or pair of underwear. The washing method must be based on the complete fibre composition, fabric structure, trims, functional components and care label.
Cotton is not automatically suitable for high-temperature washing. Satin does not automatically mean silk. Lace and microfibre do not identify one fibre. A small proportion of elastane may still be essential to the garment’s fit and support.
Read what the garment is made from, but let the complete garment and its care label determine how it should be washed.
Sources
- European Parliament and Council, Regulation (EU) No 1007/2011 on textile fibre names and related labelling and marking of fibre composition ↗.
- Cotton Incorporated, Textile Fibers ↗, 2013.
- International Sericultural Commission, Silk — An Introduction ↗.
- International Organization for Standardization, ISO 5157:2023 — Textiles — Environmental aspects — Vocabulary ↗.
- The George Washington University Museum and The Textile Museum, Structure ↗.
- GINETEX, Table of textile care symbols ↗.
Related articles
How to wash cotton underwear
How to protect elastane and stretch fibres in lingerie