Bamboo viscose is softer than cotton and less forgiving in the wash. Get the care right and a pair lasts years. Get it wrong and you lose the softness that was the point.
This is the short version of what actually matters.
The rules, in order of importance
- Cool wash, 30°C or below. Heat is what damages the fibre and causes shrinkage
- No fabric softener. It coats the fibres, reduces breathability and eventually makes them feel waxy
- Air dry. Tumble drying is the fastest way to lose the softness
- No bleach. It weakens the fibre structure
- Turn inside out and use a wash bag if you have one. Reduces friction and pilling
The first three do most of the work. If you only remember one thing, make it the temperature.
Can you tumble dry bamboo underwear? Yes, but only on the lowest heat, and take it out while it is still slightly damp; air drying is better. Heat is what shrinks bamboo viscose and wears out the elastane, which is why temperature comes first in the rules above. Flissie women's bamboo boxer shorts (we make them) are 95% Tanboocel bamboo viscose and 5% elastane, so the same applies: wash them cool and air dry them.
Try Flissie women's bamboo boxer shorts
£20 a pair, or £13 a pair in a 7 pack, in UK 8 to 30 at one price. Free UK delivery on every order, a free size swap on your whole first order, and a 60 day guarantee: full refund, worn or not.
Washing
Sort by colour and wash darks separately for the first few washes, as with any new garment.
Use a gentle cycle at 30°C or below. A mild liquid detergent is better than powder, which can leave residue on fine knits.
Do not overload the drum. Underwear needs room to move. A packed load means more friction, which is what causes pilling.
Keep them away from heavy items. Towels, jeans and anything with a zip will abrade fine fabric.
Hand washing
Cool water, a small amount of mild detergent, gentle agitation for a few minutes, then rinse until the water runs clear. Our step-by-step guide to hand washing underwear goes through it in detail.
Do not wring them out. Press the water out between your palms or roll them in a towel. Wringing distorts the knit and stretches the elastane.
Drying
Air dry, flat or hung, out of direct sun. Strong sunlight fades colour and can make the fibre brittle over time.
If you must tumble dry, use the lowest heat setting and take them out slightly damp. Over-drying is what kills the elastane.
A good compromise: 20 minutes on low, then lay flat to finish.
Stains
Cold water first, always. Hot water sets protein stains, including blood.
Blot, do not scrub. Scrubbing breaks fibres and leaves a worn patch.
For stubborn marks, soak in cool water with a mild enzyme detergent for an hour before washing. An oxygen-based whitener is safer than chlorine bleach if you need one.
Storage
A drawer is fine. Folded, not crammed.
Avoid sealed plastic containers for long-term storage, which trap moisture, and cardboard boxes, which can be acidic.
Ironing
Rarely necessary. If you do, use a low setting with a clean tea towel between the iron and the fabric. Hanging them in a steamy bathroom sorts most creases without any heat at all.
How often should you wash them?
After every wear.
You will see claims that bamboo underwear can be worn multiple times because the fabric is antibacterial. That is not true, and it is not good advice. The compound sometimes credited to raw bamboo does not survive the process that turns bamboo pulp into viscose, so it is not in the finished fabric.
Wash them like any other underwear. If that means more washing than you would like, how many pairs of underwear you actually need works out the numbers.
What we make
Flissie women's bamboo boxer shorts are 95% Tanboocel bamboo viscose with 5% elastane, dyed to OEKO-TEX Standard 100, with a 6 or 9 inch leg, UK 8 to 30, every size the same price: £20 a pair, or £13 a pair in a 7 pack.
Looked after this way, a pair should last a couple of years of regular wear. See the range.
Questions
What temperature should I wash bamboo underwear at?
30°C or below. Cooler is better. Heat is the main cause of shrinkage and fibre damage in viscose.
Does bamboo underwear shrink?
It can, more than cotton, and heat is almost always the cause. A cool wash and air drying will usually prevent it. A hot wash followed by a tumble dry is the combination to avoid.
Can I tumble dry bamboo underwear?
You can, on the lowest heat, but air drying is considerably better. If you tumble dry, take them out while still slightly damp rather than letting them go bone dry.
Why should I avoid fabric softener?
It coats the fibres with a film that reduces breathability and, over time, makes the fabric feel slightly waxy rather than soft. Bamboo viscose does not need softening.
How can I keep bamboo underwear soft?
Cool wash, no softener, air dry. That is genuinely it. A splash of white vinegar in the rinse works as a natural softener if you want one, and it rinses out without residue.
How often should I wash bamboo underwear?
After every wear, the same as any underwear. Claims that bamboo can be worn multiple times rest on an antibacterial property the finished fabric does not have.
How long should bamboo underwear last?
With cool washing and air drying, a couple of years of regular wear. The elastane usually gives out before the bamboo viscose does, and heat is what shortens its life.
Can you put bamboo underwear in the washing machine?
Yes. Use a gentle cycle at 30°C or below with a mild liquid detergent, turn them inside out, use a wash bag if you have one and keep them away from towels, jeans and zips. Flissie women's bamboo boxer shorts (we make them) go in the machine on a cool, gentle cycle, so there is no need to hand wash them.
What happens if you tumble dry bamboo underwear?
On a hot setting it can shrink, lose its softness and wear out the elastane, which usually gives out first. That is why air drying is the safer choice.
How do you get blood out of bamboo underwear?
Rinse it in cold water first, never hot, because hot water sets protein stains such as blood. Blot rather than scrub, then, for a stubborn mark, soak it in cool water with a mild enzyme detergent for an hour before washing as normal.
Why is my bamboo underwear pilling?
Friction. A packed drum, heavy items such as towels and jeans, and anything with a zip all rub against the fine knit, so turn your pairs inside out, use a wash bag and leave the drum room to move.
