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Does Teeth Whitening Harm Your Teeth?

Whitening is widely used, and the evidence on side effects is reassuring when it is done properly. This guide explains what is known, and who should take care.

Key points

  • Done under a dentist's supervision, whitening commonly causes short-lived sensitivity and sore gums, and little else.
  • Stronger gel is not clearly better, and adding light does not appear to make whitening stronger.
  • Whitening only lightens natural teeth, so fillings, crowns and veneers keep their colour.
  • The NHS says products from a pharmacy, online or a salon do not work as well and may harm teeth and gums.1
  • Have a dental examination first, treat decay and gum disease, and follow the instructions exactly.

A common question is whether whitening damages the teeth. The honest answer is that, done under a dentist's supervision on healthy teeth, the common side effects are short-lived. Problems are more likely with unsupervised products, strong gels used without care, or teeth that are not healthy.

The common side effects

Sensitivity to cold or sweet food and drink is a known side effect of whitening, and so are sore gums or throat and white patches on the gums.1 These tend to settle in a short time.1 A meta-analysis found no difference in the risk or intensity of sensitivity between at-home and in-office bleaching.2

Sensitive teeth are very common even without whitening: dentine hypersensitivity, the medical name for sensitive teeth, causes pain and discomfort and affects quality of life.6 If you already have sensitive teeth, discuss them with your dentist before whitening. See our guide to sensitive teeth.

The strength of the gel

Stronger gel is not clearly better. A review of 14 studies with 649 patients found that 35 percent hydrogen peroxide caused more sensitivity than 6 to 20 percent gels, and that the lower strengths changed the colour more on instrumental measures, though patients did not see a clear difference in shade.3 Using a lower strength may give the same visible result with less discomfort.

Light or laser

Adding light does not appear to make whitening stronger. A meta-analysis of 21 trials found that adding light to in-office bleaching gave no improvement in colour change and did not change sensitivity.5 If a clinic uses a lamp, you can ask whether it affects your comfort, but it does not seem to add to the result.

Effects on fillings, crowns and veneers

Whitening only lightens natural teeth, so fillings, crowns and veneers keep their colour, and they may stand out against lighter teeth.1 In laboratory studies, bleaching can affect restorative materials, although no clinical report was found of a restoration that had to be renewed because of it.4 Ask your dentist what to expect if you have visible dental work.

What about enamel?

Laboratory studies have raised questions about effects of bleaching on enamel, and the research is not as clear as headlines suggest. The main findings in patients are the temporary side effects described above. If you have worn enamel, cracks or exposed roots, whitening may be uncomfortable, and your dentist may advise caution or a different approach.

Who should not have whitening

The NHS lists several groups who should not have it: people aged 17 or younger, people with unhealthy teeth or gums, people who are pregnant or breastfeeding, and people with crowns, dentures or implants, for whom it does not change the colour.1 Decay and gum disease should be treated first.

Unsupervised products

The NHS says products from a pharmacy, online or a salon do not work as well and may harm your teeth and gums, and that strong whitening gels should only be used or sold by dental professionals who know how to use them correctly.1 Be cautious about kits that promise dramatic results, home remedies with acids or abrasives and products that do not state their ingredients.

How to reduce the risks

  1. Have a dental examination first, and treat decay and gum disease.
  2. Use a dentist-supervised method.
  3. Ask for a lower-strength gel if you are prone to sensitivity.
  4. Follow the instructions exactly, and do not overuse.
  5. Use a desensitising toothpaste if you feel sensitivity.
  6. Protect your gums, and tell your dentist about any soreness.
  7. Do not whiten more often than your dentist advises.

What to do if something goes wrong

  • Sensitivity: stop for a few days, use a desensitising toothpaste and avoid very cold or hot food. If it persists, see your dentist.
  • Sore gums: rinse with warm salt water, and tell your dentist.
  • White patches on the gums: these usually fade, but mention them.
  • Severe or persistent pain: see your dentist promptly.

How long the effects last

The result is not lasting, and with your dentist's advice it may last around three years.1 Read our guide to how long whitening lasts. For the range of methods, see types of teeth whitening and our page on teeth whitening.

What a supervised whitening process involves

A supervised process has several steps, and each protects you.

  1. Examination. The dentist checks your teeth and gums, takes X-rays if needed and treats decay or gum disease first.
  2. Finding the cause of the colour. Stain from tea, coffee or smoking responds differently from darker colour inside the tooth, and the dentist advises what is likely to work.
  3. Choosing a method. This may be trays worn at home with gel prescribed by the dentist, or treatment at the clinic with protection for the gums.
  4. Protection. The gums are protected from the gel, and you are told how long and how often to use it.
  5. Review. The dentist checks the result, advises on sensitivity and says how to keep the colour.

This is why the NHS advises seeing a dentist, and why products without these steps carry more risk.1

A plan if your teeth are prone to sensitivity

Some people find whitening uncomfortable. If you already have sensitive teeth, discuss it before you start.

  • Use a desensitising toothpaste for a couple of weeks beforehand, as the dentist advises.
  • Ask for a lower-strength gel, or for shorter sessions.
  • Spread treatment over more days, instead of doing it all at once.
  • Avoid very cold and very hot food and drinks while you are whitening.
  • Stop and call your dentist if the sensitivity is sharp or does not settle.

Sensitivity is usually temporary and eases when the treatment stops, but you should not push through pain.

Keeping your results

Whitening is not lasting, so how you look after your teeth matters. Limit tea, coffee, red wine and cola, or brush or rinse afterwards. Do not smoke, since smoking stains teeth. Brush twice a day, clean between the teeth and keep your dental check-ups, where a professional clean removes surface stain. Ask your dentist whether a top-up is suitable, and how often, and do not repeat treatment more often than advised.

Questions to ask before whitening

  • Why is my tooth colour the way it is, and is whitening likely to help?
  • Which method do you suggest, and how strong is the gel?
  • How will you protect my gums?
  • What can I do if my teeth become sensitive?
  • How long should the result last, and how do I keep it?
  • Will my fillings, crowns or veneers need to be matched afterwards?

A clear, unhurried answer to each is a good sign that the whitening is being managed carefully, and the NHS advises that treatment is carried out by a dentist or a person working under a dentist's supervision.1

Myths and facts

Myth: whitening always wrecks enamel. The common effects in patients are temporary sensitivity and sore gums, which usually settle.1

Myth: home kits are as good as a dentist's. The NHS says they do not work as well and may harm teeth and gums.1

Fact: a check-up first protects you. Decay or gum disease makes whitening uncomfortable.

Who should check with a dentist first

  • Anyone with sensitive teeth or exposed roots.
  • Anyone with receding gums, cracks, worn enamel or untreated decay.
  • People with many fillings, crowns or veneers, because of colour matching.
  • People who grind their teeth, who may already have sensitivity.
  • Anyone who has had an allergic reaction to dental products.

Keeping a perspective

For most healthy adults, whitening done under supervision causes short-lived sensitivity and little else. It is a cosmetic treatment, so it is reasonable to weigh the benefit against the discomfort and to decide whether you want it. If you do not, a professional clean and cutting down on staining drinks can improve appearance with no risk at all.

Frequently asked questions

Will whitening make my teeth more sensitive for ever?

Sensitivity tends to settle in a short time.1

Can I whiten if I have fillings?

Yes, but fillings will not change colour, so they may look different afterwards.1

Is whitening suitable during pregnancy?

The NHS lists people who are pregnant or breastfeeding among those who should not have it.1

How often can I whiten?

Ask your dentist. Overuse can increase sensitivity.

Does whitening cause cavities?

Whitening does not cause cavities, but decay should be treated first, because whitening untreated decay can be uncomfortable.

Are natural remedies better?

Not necessarily. Some, such as acids or abrasives, can harm enamel. Ask your dentist.

Can I whiten my teeth during pregnancy?

Many dentists advise waiting, as there is little research on whitening in pregnancy and it is not essential. Ask your dentist.

Will whitening work on all stains?

No. Stain from food, drink and smoking usually responds, while stains from within the tooth, from some medicines or from injury may respond less. A dentist can tell you what to expect.

Does whitening need to be repeated?

The effect is not lasting, so many people choose a top-up. Ask your dentist how often it is suitable for you and do not repeat it more often than advised.1

About the author

Portrait of Dr Anupam Sinha

Dr Anupam Sinha, BDS, MDS – Orthodontics. BDS (2002), KLE Vishwanath Katti Institute of Dental Sciences, Belgaum. MDS in Orthodontics (2006), SDM College of Dental Sciences, Dharwad. His thesis work won a national research award in 2005, and he holds a certification in aesthetic dentistry. He sees patients at Orion Dental Clinic in Greater Kailash 1, South Delhi. Read the full profile of Dr Anupam Sinha.

Sources

  1. NHS website. Teeth whitening (patient information). Page review date 19 August 2025. https://www.nhs.uk/conditions/teeth-whitening/
  2. de Geus JL, Wambier LM, Kossatz S, Loguercio AD, Reis A. At-home vs in-office bleaching: a systematic review and meta-analysis. Operative Dentistry, 2016;41(4):341-356. https://pubmed.ncbi.nlm.nih.gov/27045285/
  3. Pontes M, Gomes J, Lemos C, Leao RS, Moraes S, Vasconcelos B. Effect of bleaching gel concentration on tooth color and sensitivity: a systematic review and meta-analysis. Operative Dentistry, 2020;45(3):265-275. https://pubmed.ncbi.nlm.nih.gov/32396502/
  4. Attin T, Hannig C, Wiegand A, Attin R. Effect of bleaching on restorative materials and restorations: a systematic review. Dental Materials, 2004;20(9):852-861. https://pubmed.ncbi.nlm.nih.gov/15451241/
  5. Maran BM, Burey A, de Paris Matos T, Loguercio AD, Reis A. In-office dental bleaching with light vs. without light: a systematic review and meta-analysis. Journal of Dentistry, 2018;70:1-13. https://pubmed.ncbi.nlm.nih.gov/29289725/
  6. Grover V, Kumar A, Jain A, Chatterjee A, Grover HS, Pandit N, et al. ISP good clinical practice recommendations for the management of dentin hypersensitivity. Journal of Indian Society of Periodontology, 2022;26(4):307-333. https://pubmed.ncbi.nlm.nih.gov/35959314/

Medically reviewed by Dr Anupam Sinha, BDS, MDS – Orthodontics, on . General information for patients from Orion Dental Clinic, last updated 23 October 2026. It is not advice for one person, so ask a dentist what suits you. To report an error, contact us.