Joybuy Insights

Buying underwear: how to choose the right fit, fabric and multipack without making the wrong choice

Buying underwear may seem simple, but you often only notice a poor choice after wearing it for a few hours. A waistband that digs in, legs that ride up or fabric that loses its shape after a few washes can turn a bargain into an expensive mistake. Marketing terms such as “seamless”, “antibacterial” or “sporty” also don’t always tell you enough about the fabric, sizing or care instructions.

Use these checks to compare men’s underwear, women’s underwear, multipacks and specialist styles by practical features. That way, you can make a more informed choice for everyday wear, sport, travel or outfits where a smooth finish matters.

Three common pitfalls when buying underwear

1. Looking only at the letter size

A size S, M or L won’t be the same across every brand. So check the size guide for the specific product. Look at your waist or hip measurement, the rise and the cut. A low-rise trunk fits differently from a regular-waist style. For women’s briefs and thongs, hip measurement is particularly relevant; for men’s boxers and boxer shorts, waist and leg length also come into play.

2. Mistaking a fabric name for the full composition

“Cotton”, for example, may be blended with elastane, polyester, modal or polyamide. This affects stretch, weight and how the garment feels after washing. Always check the percentage of each fibre. Under the EU regulation on textile fibre names, Regulation (EU) No 1007/2011, the fibre composition must be stated on the label.

3. Treating a functional claim as a guarantee

A brand may mention features such as moisture management, reduced friction or an antibacterial gusset lining. Treat these as information from the product description, not as a guaranteed result. For example, according to Calvin Klein’s product description, one style has a plant-based moisture-wicking finish; according to Utree’s product description, its women’s style has a “10A antibacterial gusset”. These claims come from the brands or sellers. Also check the fabric, seams, waistband and care instructions.

The key specifications to compare

Fit and construction

Choose a cut to suit your clothes and activity:

  • Trunks have short legs and generally offer more coverage than briefs.
  • Men’s boxer shorts with longer legs can be comfortable under trousers if you want to reduce friction between your thighs. According to Reebok’s product description, its sports trunks are designed for everyday wear and sport.
  • Women’s briefs with a mid waist offer more coverage around the tummy than a low-rise style.
  • Women’s thongs offer minimal coverage and may be less visible under close-fitting clothes.
  • Seamless underwear or styles with flat edges are particularly practical under lightweight dresses, skirts or trousers. Check whether “seamless” applies to the whole garment or just the leg openings and waistband.

Look for a waistband that’s firm enough to stay in place without digging in. A leg opening that’s too loose may ride up, while an edge that’s too tight can become uncomfortable.

Fabric and stretch

Cotton underwear is a practical choice for everyday wear for many people. Cotton generally feels soft and is easy to wash. Elastane adds stretch and helps the garment retain its shape. A modal blend may feel smoother, while polyamide and elastane are often used for lightweight, stretchy or smooth styles.

Don’t just look for the word “soft”. Also check:

  1. the fibre percentages;
  2. the fabric’s thickness and strength;
  3. the composition of the gusset or lining;
  4. whether it has hard seams, labels or decorative details.

For disposable underwear, check the number of pieces, size, fabric and intended use. Disposable styles can be useful for travel, camping or a stay where washing is difficult. They aren’t automatically the most economical choice for everyday wear.

Care instructions and expected lifespan

How long underwear lasts depends on the fabric, how often you wear it and how you care for it. Wash it at the temperature stated on the label and don’t use bleach unless permitted. Several product descriptions advise against tumble drying. A low temperature or air-drying can help put less strain on elastic fibres and waistbands.

An underwear multipack is practical if you want several identical styles to rotate. Still, compare the price per item and consider whether you already know the fit works for you. A pack of three or five isn’t such good value if you end up not wearing the style.

Recommendations for different shoppers

Suitable for: Budget-conscious beginners
Reebok RBK SPORTS TRUNKS MED BEXLEY

Reebok RBK SPORTS TRUNKS MED BEXLEY

Why it suits this shopper: The 3-pack gives you a practical supply for everyday wear without having to mix and match different styles straight away. The product description mentions a flexible waistband and a supportive fit.

How this product avoids the pitfall

You can see the number of items and intended fit straight away. Before ordering, make sure you check the available size and full fabric composition.

Key benefit & highlights

3 items per pack; flexible waistband; according to the product description, suitable for everyday wear and sport.

Suitable for: Shoppers looking for top quality
Calvin Klein 3-Pack Slim Boxers

Calvin Klein 3-Pack Slim Boxers

Why it suits this shopper: This style is aimed at anyone looking for a close-fitting cut, a well-known brand and classic colours for work and leisure.

How this product avoids the pitfall

The product information lists a cotton-stretch blend, a 3-pack and a 30 °C machine wash. This lets you compare the fabric, pack size and care instructions in advance.

Key benefit & highlights

Slim fit; three colours per pack; elasticated waistband; cotton-elastane blend according to the product description.

Suitable for: Specific needs & frequent wearers
LEE SEAMLESS BRIEF SILE

LEE SEAMLESS BRIEF SILE

Why it suits this shopper: These smooth, stretchy briefs are designed for anyone who wants an unobtrusive style under clothes and wears a flexible fit regularly.

How this product avoids the pitfall

The product description lists 90% polyamide and 10% elastane, a smooth fit and a 30 °C wash. Check, though, whether these fibres suit your preference for cotton underwear.

Key benefit & highlights

Stretch construction; multipack available according to the product description; tumble drying, bleach and ironing are not recommended.

Suitable for: Travellers and temporary situations
Deeyeo Women's Disposable Underwear

Deeyeo Women's Disposable Underwear, 7-pack

Why it suits this shopper: A pack of seven can be practical for travel or situations where washing isn’t easy.

How this product avoids the pitfall

The number of items and size L are stated in the product name. Before buying, check the current product information on fabric, fit and intended use.

Key benefit & highlights

7 items per pack; designed for single use; compact to pack according to the product name.

Looking for more options?

We’ve put together a complete, up-to-date list of products that meet these strict selection criteria and the applicable European safety regulations.

Frequently asked questions about buying underwear

How often should you replace your underwear?

Replace your underwear when the fabric starts to thin, the elastic loses its stretch, seams come apart or stains and odours remain after washing. There’s no set timeframe that works for everyone. Rotating several sets and following the care instructions can help keep garments wearable for longer.

Is cotton always the right choice?

Not always. Cotton is a practical option for everyday wear, but a blend with elastane can offer more stretch. For a smooth look under clothes, a polyamide-elastane style may be a better choice. Compare the full composition with your own preferences and intended use.

Are multipacks cheaper than individual items?

That depends on the price per item and how often you wear the style. Divide the total price by the number of items, and check the fabric composition, size and care instructions at the same time. An underwear multipack is most useful when you already know the fit works for you.