Last Updated on October 4, 2026 by Umar Farooq
Turn them inside out, put them in a mesh bag, wash cold on a gentle cycle with the lowest spin the machine offers, skip fabric softener entirely, and lay them flat or drape them to dry. Never with towels, denim or zips, and never in a hot dryer. Pilling comes from abrasion; a slack waistband comes from heat.
Leggings fail in two ways and people treat them as one problem. The surface goes fuzzy, and the fit goes slack. Different causes, different fixes, and the advice that helps one does very little for the other.
Pills stay on leggings because the fibre is too strong to let go
Everyone knows pilling is caused by rubbing. The part that explains why leggings get it worse than a cotton T-shirt is the bit nobody writes down: the pills on a synthetic do not fall off. The clearest statement of it sits in a patent for low-pill polyester, where the mechanism has to be set out before the invention can address it.
Verbatim: “pills can be traced to the relatively high strength of the synthetic fibers present in the fabric. For instance, the pills may be more or less permanently attached to the fabric’s surface by one or a few synthetic polymeric fibers extending out of the fabric which will resist breakage as surface abrasion continues” (production of a fabric containing polyethylene terephthalate fibers having a reduced tendency to pill, US 4,666,454). The same document explains why cotton behaves differently: entangled cotton fibres “readily break away since the cotton fibers are of an inherently lesser strength.”
So a cotton jumper and a pair of leggings form pills at a similar rate. On the jumper they snap off and vanish; on the leggings they are tethered by a filament engineered not to break, and they accumulate. The patent even names the fabric type that shows it most: “they frequently are observed on knitted fabrics which comprise polyethylene terephthalate fibers.” Leggings are exactly that.
Woolmark, writing about wool but describing the same phenomenon, is honest about the limits: “Because pilling is so complex, nobody can guarantee that it won’t occur” (what is pilling). You are reducing abrasion, not eliminating a possibility.
Sagging is lost recovery, not stretch
The second failure has nothing to do with the surface. Elastane does not simply stretch out; it loses recovery, the ability to pull back to its original length after being extended. A pair that has lost recovery goes baggy at the knee within an hour of putting them on, then looks fine again after a wash, then goes baggy again faster.
Heat is the main agent, and the dryer supplies more of it than any wash. Whirlpool: “High heat from a dryer can damage the delicate synthetic fibers like spandex, causing them to lose their stretch. If you must use a dryer, select the lowest possible heat setting or a no-heat, air-fluff cycle” (how to wash leggings). Worth noting that page carries its own disclosure — “This article includes AI-generated content that our human team has reviewed and edited to ensure quality” — so treat it as a brand’s guidance rather than as engineering documentation.
The waistband goes first because it does the most work and holds the most elastic. It is also the part people hang the wet garment by, loading a saturated garment onto the one component you most want to leave alone. Drape them over the bar folded at the knee instead, so the weight is shared (why do clothes shrink in the wash).
How to wash leggings so the waistband still holds
Six steps, and the first two matter more than the rest combined because both target abrasion, which is the failure you cannot reverse.
- Inside out. The outer face is what shows pills, so give the abrasion to the inside.
- Mesh bag. Whirlpool: it “helps prevent them from getting stretched, snagged or tangled with other items that may have zippers, buttons or hooks.”
- Cold water, gentle or activewear cycle. Warm water buys nothing on a garment whose soil is sweat and skin oil.
- Lowest spin available. Spin force stretches a saturated knit against the drum wall.
- No fabric softener. Whirlpool again: it leaves “a waxy coating on the fibers that can inhibit the moisture-wicking properties of the fabric.”
- Air dry flat, or draped, out of direct sun.
On frequency, Whirlpool’s position is firmer than most: leggings “should generally be washed after every wear, especially if used for a workout”, and for casual low-sweat wear “two to three wears between washes”. Their reason is that sweat and body oils “can degrade the delicate elastic fibers, like spandex or elastane, over time” — so the fibre argument runs both ways, and leaving them unwashed is not the conservation strategy it looks like.
Hand washing is the advice everyone gives, and mostly it is not needed
Here is the position. Every page ranking for this query tells you hand washing is best, and for leggings specifically that advice is close to wasted effort. The two things that destroy a pair are abrasion against heavier fabrics and heat. A mesh bag removes the first and selecting air dry removes the second — both achievable in a machine, in a cycle you were running anyway.
What hand washing adds is control over temperature, which a cold tap already gives you, and the absence of spin, which a low spin setting mostly gives you. What it introduces is the risk of wringing, and wringing a wet knit does more damage in five seconds than a gentle cycle does in forty minutes.
Hand wash the pair with the mesh panels and the printed graphic. For the plain black pair you wear three times a week, the machine is fine (what cycle for delicates and activewear).
Taking the pills off a pair you already own
Pills already formed will not wash out, because the thing holding them on is a filament stronger than the wash. They have to be cut off. Woolmark’s assessment of the tool is straightforward: battery-operated “de-pillers” or fabric shavers are “low cost and very effective at removing pills, giving your clothing an as-new appearance again.”
Run the shaver over fabric laid flat, never stretched over your hand, and start on the lowest setting somewhere nobody sees. A shaver cuts, and stretched knit presents more surface to the blade than you intended — which is how people put a hole in the thigh of a perfectly good pair. A garment already thinning at the seat is one to leave alone (washing machine tearing clothes).
FAQ
How often should you wash leggings?
After every workout. For casual wear Whirlpool suggests two to three wears, and their reasoning is that body oils degrade elastane rather than that washing does. The old advice to wash activewear as rarely as possible is backwards.
Can you put leggings in the dryer?
Only on no-heat or the lowest setting, and even then it is the main thing shortening their life. Heat is what takes the recovery out of elastane, and recovery is what makes leggings fit. Air drying is the single highest-value habit here.
Why do my leggings pill between the thighs?
Because that is where fabric rubs fabric all day, and on a synthetic knit the resulting pills cannot break away. Wear causes it, washing accelerates it, and a shaver is the only thing that removes it once it has happened.
Does washing leggings inside out actually help?
Yes, and more than it helps most garments. It puts the abrasion of the wash on the inner face while the outer face, the one whose pilling you would notice, is protected. It also puts the sweat and skin oil where the water is.
Can you use fabric softener on leggings?
No. It deposits a coating that blocks the fabric’s moisture movement, and on a technical knit that is the property you paid for. It also seals body oil into the fibre, so the garment gets harder to clean over time.
Two years is a good run
Leggings are a consumable with an unusually long life, not a permanent garment. Cold, bagged, low spin and air dried, a pair worn twice a week holds its shape and surface for a long time. Washed hot with towels and tumbled dry, the same pair is baggy and fuzzy by spring.
The pills are the wash. The sag is the dryer.
