Custom trays and a milder gel, guided by a dentist
Home Teeth Whitening with Custom Trays
Home teeth whitening means you wear thin, custom-made trays filled with a mild peroxide gel, following a plan from your dentist. It lightens natural teeth gradually over a few weeks. However, a dentist should check your teeth and gums first, because whitening only suits healthy mouths and it does not change crowns, veneers or fillings.
At a glance
- What you use
- Custom-made trays and a carbamide or hydrogen peroxide gel
- UK limit on the gel
- Up to 6% hydrogen peroxide, supplied only through dentists
- Typical course
- About 2 to 6 weeks, according to the NHS
- Compared with in-office
- Similar colour change in reviews of trials
- Most common side effect
- Mild, short-lived tooth sensitivity
- How long results last
- Often 1 to 3 years, then colour fades gradually
These figures come from UK health bodies and research reviews rather than from any one clinic. Your dentist confirms your plan after an in-person examination.
How home teeth whitening works
First, a dentist examines you to make sure your teeth and gums are healthy. Next, they take a scan or impression and make trays that fit your teeth closely. Then you place a small amount of gel in the trays and wear them as your dentist directs, often daily or overnight.
The gel contains carbamide peroxide or hydrogen peroxide. Carbamide peroxide releases hydrogen peroxide, which is what lightens the tooth. In UK and EU rules, gels between 0.1% and 6% hydrogen peroxide may only be sold to dentists. Also, the first use should take place with a dentist.
Because the gel is milder than in-office gel, home teeth whitening works gradually. For example, the NHS says a course often takes around 2 to 6 weeks. Meanwhile, one 2025 review found daily use of 10% carbamide peroxide for three to four weeks effective.
- 1
Custom trays for home teeth whitening
First, your dentist makes soft trays from a scan or impression of your teeth. Because they fit closely, they help keep the gel on your teeth. You can keep the trays for later top-ups.
- 2
A lower-strength gel
Reviews found that 10% carbamide peroxide whitened as well as stronger gels, with less sensitivity. So many dentists start low.
- 3
Your dentist in charge
UK rules say only registered dental professionals may provide whitening. In addition, the first cycle of use starts with a dentist, and you finish it at home.
Who home teeth whitening may suit
Suitability is individual. A dentist weighs these points after examining your teeth and gums. So treat them as a guide rather than a checklist.
Home teeth whitening may be considered if
A different plan may be safer if
Home teeth whitening compared with other options
Each option has a place. However, most trials are small, and reviews rate much of the evidence as low quality. So compare them with care.
Your home teeth whitening journey
For international patients, the trays and the first use usually happen in Istanbul. Then you carry on whitening at home. Your dentist will confirm how many days you need to stay.
- 1Online
Remote review
First, you send photos of your smile. Then a dentist explains whether whitening, or another option, looks suitable.
- 2In Istanbul
Examination
When you arrive, your dentist checks your teeth and gums. Next, they record your starting shade and agree the plan with you.
- 3In Istanbul
Scans and trays
After that, your dentist takes a scan or impression. Then a technician makes trays that fit your teeth closely.
- 4In Istanbul
First use with your dentist
Next, your dentist shows you how much gel to use and how to wear the trays. Under UK and EU rules, this first use happens with a dentist.
- 5At home
Home teeth whitening
Back home, you wear the trays as directed, often for a few weeks. If your teeth feel sensitive, you contact your dentist.
- 6Later
Top-ups and check-ups
Over time, the colour fades a little. So you can reuse your trays for a short top-up, with advice from a dentist.
Getting the most from home teeth whitening
Wearing your trays
Follow your dentist's plan for how long to wear the trays. Trials used many schedules, and no single one proved best. So more gel or longer wear is not always better.
Food and drink
In trials, avoiding coloured food and drink during treatment did not change the result. Still, smoking, tea, coffee and red wine bring stains back faster over time.
Managing sensitivity
If your teeth feel sensitive, tell your dentist. For example, they may suggest a break or a desensitising product, because potassium nitrate and fluoride reduced sensitivity in trials.
Top-ups later
Results often last one to three years, although this varies. When the colour fades, your dentist may suggest a short top-up with your existing trays.
Risks of home teeth whitening
Side effects of home teeth whitening are usually mild and short-lived. For example, a Cochrane review of 71 trials found that sensitivity and gum irritation were the most common problems. They were also more frequent with stronger gels.
However, the bigger risk often comes from unsupervised products. The NHS warns that kits from shops, online sellers or beauty salons may not work as well and may harm your teeth and gums. For this reason, UK rules keep stronger gels for dental professionals only.
For example, your teeth may feel sensitive to cold or sweet things. Usually it is mild and fades. Still, higher concentrations raised the risk in a 2025 review, so dentists often choose a milder gel.
Gel on the gums can make them sore, or leave white patches for a short time. So well-fitting trays and the right amount of gel matter.
In addition, the NHS lists a sore throat among possible side effects. Therefore, follow your dentist's advice on how much gel to use.
Whitening does not change the colour of fillings, crowns or veneers. As a result, they may stand out once your natural teeth are lighter.
Kits from shops, online sellers or beauty salons may harm your teeth and gums. In addition, anyone who is not a registered dental professional may not legally provide whitening in the UK.
Whitening is not permanent. In most studies, colour stayed stable for 1 to 2.5 years, and severe stains tended to return more.
Questions to ask about home teeth whitening
A good dentist will welcome these questions. So write down the answers, and compare them before you decide.
- 1Are my teeth and gums healthy enough for whitening?
- 2Which gel will I use, and at what strength?
- 3How long should I wear the trays each day, and for how many weeks?
- 4What should I do if my teeth become sensitive?
- 5Will my fillings, crowns or veneers still match afterwards?
- 6How do I get gel for top-ups later, and who supervises them?
Home teeth whitening FAQs
In reviews of trials, both gave similar colour change on shade guides. One 2025 review even measured slightly more change with home trays, although the evidence was low quality. In-office whitening is simply quicker.
It varies with the gel and your plan. The NHS says around 2 to 6 weeks, while the Oral Health Foundation says 1 to 2 weeks is typical. So your dentist will give you a schedule.
In the UK, products sold to the public may contain no more than 0.1% hydrogen peroxide. As a result, they may lift some surface stains but change the colour very little.
Yes, some dentists do. However, one review found that adding in-office whitening to home trays did not improve colour, but it did increase sensitivity.
UK and EU rules allow gels above 0.1% hydrogen peroxide only through dentists, after an examination. Also, the first use should happen with a dentist, and you then finish at home.
Usually, yes. The Oral Health Foundation says trays can be kept and reused. Ask your dentist how to get more gel safely.
Related guides
Medical review required before publication · General information only; it does not replace an examination, diagnosis or personalised treatment plan.
- NHS. Teeth whitening (reviewed 2025)
- Oral Health Foundation. Tooth whitening (updated 2026)
- General Dental Council. What the law says: tooth whitening (2019)
- General Dental Council. Direct access and tooth whitening (2025)
- Council Directive 2011/84/EU on hydrogen peroxide in tooth whitening products (2011)
- Eachempati P et al. Home-based chemically-induced whitening (bleaching) of teeth in adults. Cochrane review (2018)
- de Geus JL et al. At-home vs in-office bleaching: an updated systematic review and meta-analysis (2025)
- Aidos M et al. Comparison of in-office and at-home bleaching techniques: an umbrella review (2024)
- Kury M et al. Clinical decision-making in tooth bleaching based on current evidence: a narrative review (2025)
- de Geus JL et al. At-home bleaching with 10% vs more concentrated carbamide peroxide gels: a systematic review and meta-analysis (2018)
- Terra RMO et al. Effect of at-home bleaching agents and concentrations on tooth sensitivity: a network meta-analysis (2025)
- Terra RMO et al. Effect of at-home agents and concentrations on bleaching efficacy: a network meta-analysis (2025)
- Luque-Martinez I et al. Comparison of efficacy of tray-delivered carbamide and hydrogen peroxide for at-home bleaching (2016)
- Wang Y et al. Potassium nitrate and sodium fluoride as desensitizing agents during tooth bleaching: a meta-analysis (2015)
- da Rosa G et al. Effectiveness of whitening strips use compared with supervised dental bleaching: a systematic review and meta-analysis (2020)
- de Oliveira MN et al. Color changes and adverse effects of over-the-counter bleaching protocols: a network meta-analysis (2024)
- Fioresta R et al. Prognosis in home dental bleaching: a systematic review (2023)
- Cardenas AFM et al. Are combined bleaching techniques better than their sole application? (2019)
- Hardan L et al. Is a white diet necessary for tooth bleaching procedures? A systematic review and meta-analysis (2024)
Is home teeth
whitening right
for you?
First, send a few clear photos of your smile. A dentist will then review them and explain whether home teeth whitening, in-office whitening or another option looks suitable. Your plan stays provisional until you're examined in person.