The elastic in your underwear has gone slack and why that happens

Short answer: Elastic gives up when it meets heat, chlorine and fabric softener. Wash cool, skip the softener and dry the garment so the waistband carries no weight.

Heat is the main culprit

A waistband is rubber or elastane wrapped inside yarn. Heat takes the spring out of that material, and it happens both in the washing machine and in the tumble dryer. A pair tumbled hot on a regular basis loses its waistband within a year, while the same pair dried cool lasts several years. See bamboo underwear briefs for men.

Softener and conditioning products

Fabric softener leaves a film around the fibres and makes elastic smooth and sluggish. It feels softer the first few times and slack after that. Chlorine and bleach attack elastane directly and that damage is permanent. Use a plain detergent with no additives.

How to handle the waistband

Never lift a wet garment by the waistband when you hang it up. Lay it flat or drape it over the line at its middle so the weight does not pull on the elastic. Do not fold the waistband over when you put clothes away, because a permanent crease in elastic does not recover.

When the elastic is finished

When the band no longer pulls back after you stretch it, the elastane has broken down and cannot be saved. That is the moment to take the pair out of rotation. See bamboo briefs for women and bamboo underwear for women.

Frequently asked questions

Can slack elastic be tightened again

No, not once the elastane has broken down. It can be replaced but not revived.

How many washes should a waistband last

Washed cool and without softener, most waistbands last a few hundred washes.

Is the tumble dryer completely out

No, but use the coolest programme and take the garment out while it is still slightly damp.