Myths and facts

Do underwire bras cause breast cancer?

In brief

No. Underwire bras have not been found to cause breast cancer, says The Royal Marsden NHS Foundation Trust. The idea that wires restrict the flow of lymph fluid in the breast and let toxins build up has no evidence behind it. Bras are not on the NHS list of risk factors, though a badly fitting bra can be uncomfortable.

Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths

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Reviewed by a UK GP for World Aid Network on .

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How this page is sourced: health information here comes from NHS, NICE and WHO pages, linked beside each claim. It is general information: a GP or doctor can advise on your own situation.

Quick facts

Underwire and cancer
Underwire bras have not been found to cause breast cancer
Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths
The “trapped toxins” theory
No evidence that bra wires restrict lymph flow and cause a build-up of toxins
Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths
On the NHS risk list?
No. Bras, wired or not, are not among the causes the NHS lists
Source: NHS: Causes of breast cancer in women
NHS tip for sore breasts
A properly fitted bra during the day and a soft bra to sleep in
Source: NHS: Breast pain

Key takeaways

Where did the underwire bra myth come from?

Some people thought that bra wires press on the breast and restrict the flow of lymphatic fluid, so that toxins build up and lead to cancer. The Royal Marsden, an NHS cancer hospital in London, says there is no evidence to support this, and that underwire bras have not been found to cause breast cancer.

Bras are also missing from the NHS list of things that make breast cancer more likely. That list includes being over 50, dense breast tissue, a family history of breast or ovarian cancer, certain breast conditions and higher hormone levels.

Sources: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths; NHS: Causes of breast cancer in women

Can a badly fitting bra cause problems?

It can be uncomfortable. The Royal Marsden says ill-fitting bras, especially ones that are too small, can cause pain, discomfort or swelling because the underwires dig into the skin. A bra that fits well should avoid this.

Gateshead Health NHS Foundation Trust’s breast pain leaflet says underwired bras are a personal choice. It advises that the wires should sit flat and comfortably against your rib cage and chest bone, without digging in or gaping.

Sources: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths; Gateshead Health NHS Foundation Trust: Breast pain leaflet

Can the right bra help with breast pain?

The NHS suggests wearing a properly fitted bra during the day and a soft bra to sleep in to help ease breast pain. A leaflet from Royal United Hospitals Bath NHS Foundation Trust adds that a more supportive bra can often help, and sometimes a sports or soft bra.

The NHS says breast pain by itself is unlikely to be a symptom of cancer. See a GP if the pain is not improving or painkillers are not helping.

Sources: NHS: Breast pain; Royal United Hospitals Bath NHS Foundation Trust: Breast pain (mastalgia) leaflet

Which breast changes should you get checked?

The NHS says to see a GP or doctor if you notice:

  • a lump or swelling in your breast, chest or armpit
  • a change in the skin of your breast, such as dimpling (it may look like orange peel)
  • a change in skin colour – on white skin it may look red, on black or brown skin it may look darker than usual
  • a change in the size or shape of one or both breasts
  • nipple discharge (if you are not pregnant or breastfeeding), which may have blood in it
  • a change in the shape or look of your nipple, such as it turning inwards or a rash on it

Some of these symptoms, including breast lumps, are very common and can be caused by other conditions. Having them does not definitely mean you have breast cancer, but it is important to get checked.

Source: NHS: Symptoms of breast cancer in women

Frequently asked questions

Do tight bras cause breast cancer?
Underwire bras have not been found to cause breast cancer, says The Royal Marsden NHS Foundation Trust. But bras that are too small can cause pain, discomfort or swelling because the wires dig into the skin. Wearing a bra that fits well should avoid this.

Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths

Do underwire bras block lymph drainage?
This is the theory behind the myth: that bra wires restrict the flow of lymphatic fluid in the breast and let toxins build up. The Royal Marsden NHS Foundation Trust says there is no evidence to support it.

Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths

Should I wear a bra at night?
If your breasts are sore, the NHS suggests a properly fitted bra during the day and a soft bra to sleep in. It also says breast pain by itself is unlikely to be a symptom of cancer, but to see a GP if the pain is not improving.

Source: NHS: Breast pain

What actually makes breast cancer more likely?
The NHS says you may be more likely to get breast cancer if you are over 50, have dense breast tissue, have close family who have had breast or ovarian cancer, or have certain breast conditions. Higher hormone levels and lifestyle factors such as smoking also play a part.

Source: NHS: Causes of breast cancer in women

When should I see a GP about my breasts?
The NHS says to see a GP if you have a lump or swelling in your breast, chest or armpit, any breast or nipple change that is not normal for you, or pain in your breast or armpit and a family history of breast or ovarian cancer.

Source: NHS: Symptoms of breast cancer in women

Sources and references

This page is general information, not medical advice. A GP or doctor can advise on your own situation. Source links do not imply endorsement by the NHS or another organisation. See our editorial policy.