Whitening Kits, Charcoal and Home Remedies: What the Evidence Says
This page is for anyone weighing home whitening, from charcoal, baking soda and acidic remedies to toothpastes, strips, pens and LED kits. It rates each on abrasivity, acidity and evidence. Reviews find too little evidence that charcoal products are safe or effective, while baking soda and other whitening toothpastes have evidence for removing stains.
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Medical disclaimer: This page is for general information only. It does not replace an examination or treatment by a dentist.
This page was reviewed by Dr Ibraheem Ijaz, principal dentist at Deepcar Dental Care, a General Dental Practitioner registered with the GDC under number 301711.
How can you judge a whitening claim?
Judge a whitening claim on three things: how abrasive the product is, how acidic it is, and what independent evidence supports it.
Laboratories measure abrasivity as relative dentin abrasivity (RDA): the wear a toothpaste causes on dentine compared with a standard reference slurry. Acid softens enamel for a time, and the Oral Health Foundation says brushing while it is softened can remove tiny amounts of enamel and speed up long-term tooth wear.
Independent evidence matters because a 2009 review found most studies of over-the-counter whitening products were supported by their manufacturers, and it called for independent trials.
Does charcoal teeth whitening work?
A 2017 review found too little clinical and laboratory data to support the safety and effectiveness claims made for charcoal toothpastes and powders. It called for larger, well-designed studies and advised clinicians to tell patients to be cautious with charcoal products whose claims are unproven.
The 2017 charcoal review found 13 studies of brushing with raw charcoal or soot, none meeting its criteria of a randomised controlled trial lasting 3 months or more. Two reported unspecified reductions in decay, three reported harm (more decay, enamel abrasion or an unquantified negative effect), and one found no adverse effect on oral hygiene. If you notice any change in your teeth, show it to a dentist.
A 2023 systematic review of 11 in vitro (laboratory) studies, at medium to high risk of bias, found whitening results varied and concluded that activated charcoal toothpastes whiten less than other options and can be considered less safe because of their higher abrasive potential. A 2020 laboratory study of two fluoride-free charcoal powders found them abrasive within ISO limits but more abrasive than a reference toothpaste, a powder-to-paste comparison the authors called challenging, and found naphthalene, which the authors said breaches EU regulations, in one.
Does baking soda whiten teeth?
Toothpastes containing baking soda are effective and safe for removing tooth stains, and so whitening teeth, a 2017 review concluded.
The 2017 review of baking soda toothpastes cited several clinical studies in which they removed stains and whitened better than some more abrasive toothpastes without baking soda. Most of its research used manual toothbrushes, and it encouraged more studies with powered ones.
Another 2017 review found baking soda naturally low in abrasivity, being softer than enamel and dentine. Added ingredients can raise a baking soda toothpaste's stain removal and abrasivity, but the review found even those well within regulators' safety limits. Both 2017 baking soda reviews assessed formulated toothpastes, not baking soda mixed at home.
Are lemon juice and other acidic remedies safe for teeth?
Acidic remedies can soften enamel: the Oral Health Foundation says lemons, vinegar and strawberries can, especially if consumed often or sipped over a long time.
The Oral Health Foundation defines dental erosion as the loss of tooth enamel caused by acid. As enamel wears away, the dentine underneath is exposed, teeth may look thinner or more yellow, and sensitivity or pain can develop. If you notice sensitivity, changes in how your teeth look, or think you may have dental erosion, the Oral Health Foundation advises speaking to your dental team.
The Oral Health Foundation also advises waiting at least one hour after eating or drinking before brushing, so enamel can harden again. Acid wear is explained on the page about dental erosion from acid, and brushing on the page about brushing technique.
Does whitening toothpaste work?
Whitening toothpastes remove surface stains better than regular toothpastes, systematic reviews find, though a 2020 review rated the evidence low to moderate quality.
A 2020 systematic review found whitening toothpastes more effective than regular ones at reducing surface stain and producing a whitening-like effect, but they also caused more adverse effects. They performed about as well as paint-on gels and less well than whitening strips; the authors called for larger, independent studies. NHS guidance on teeth whitening advises talking to your dentist about any side effects that bother you.
A 2018 review found nearly all toothpastes formulated for whitening reduced surface discolouration, with or without an added chemical agent. Because toothpastes act on surface stains, intrinsic and extrinsic staining is worth understanding before choosing one.
Questions about this treatment? Book online or call the practice.
What are optical whitening toothpastes?
Optical whitening toothpastes contain blue covarine, a blue pigment designed to change how tooth colour is seen. A 2008 laboratory study found it deposits on the tooth surface and increases measured and perceived whiteness.
The evidence on blue covarine is mixed. A 2026 meta-analysis of human studies found improved tooth colour and perceived brightness against placebo or other methods, noting study heterogeneity and small samples, and called for research on long-term safety and effects. Two 2021 randomised trials found no significant whitening benefit, after a single brushing and over 2 weeks.
Do whitening strips, pens and peroxide rinses work?
Whitening strips have some short-term evidence, reviews find, though the 2020 review's strip studies used 5% to 14% hydrogen peroxide. Pens have little evidence, and low-peroxide rinses have some whitening effect without clinical relevance.
A 2020 review, calling for better-designed studies, reported strips effective against placebo and other over-the-counter products, in studies at 5% to 14% hydrogen peroxide, mostly funded at least partly by manufacturers, and found a lack of evidence on paint-on gels, the form whitening pens take. It found no clinical studies of rinses.
A 2009 review found strips gave results and side effects similar to 10% carbamide peroxide trays, but in short-term, manufacturer-funded studies; it found low-peroxide rinses and paint-on brushes had some whitening effect, but without clinical relevance. NHS guidance on teeth whitening advises talking to your dentist about any side effects that bother you.
The 2009 review noted that laws vary widely between countries, so the strip studies in both reviews may not reflect UK products. In the UK, the General Dental Council (GDC) describes products containing or releasing less than 0.1% hydrogen peroxide, including mouth rinses, as safe and freely available. The page on choosing between professional whitening and shop-bought kits sets the two routes side by side.
Do LED whitening kits work?
The over-the-counter reviews cited here did not assess home LED lights, so they give no evidence on what the light adds.
An LED kit adds a light to a whitening gel that, sold to the public, may contain or release at most 0.1% hydrogen peroxide. NHS guidance says teeth whitening from other places, like beauty salons, or with a kit bought from a pharmacy or online, does not work as well and may harm your teeth and gums.
How do home whitening remedies compare on the evidence?
The table sums up each remedy's evidence and point to watch.
| Remedy | What the evidence says | Point to watch |
|---|---|---|
| Charcoal toothpastes and powders | Too little data to support safety or effectiveness claims (2017 review) | Higher abrasive potential in most laboratory studies (2023 review, medium-high risk of bias) |
| Baking soda toothpastes | Effective and safe for stain removal (2017 review) | Low abrasivity; added ingredients can raise it, within regulators' limits (2017 review) |
| Lemon juice, vinegar, strawberries | - | Acidic; can soften enamel, especially if consumed often or sipped over a long time (Oral Health Foundation) |
| Whitening toothpastes | Reduce surface stain more than regular toothpastes; low to moderate quality evidence (2020 review) | More adverse effects than regular toothpastes (2020 review) |
| Blue covarine toothpastes | Mixed: improved colour in a 2026 meta-analysis; no significant whitening benefit in two 2021 trials | Long-term safety needs more research (2026 meta-analysis) |
| Whitening strips | Effective against placebo, in studies at 5% to 14% hydrogen peroxide (2020 review); short-term (2009 review); in both, studies mostly funded at least partly by manufacturers | UK retail limit: 0.1% hydrogen peroxide |
| Whitening pens | Lack of evidence (2020 review); some effect without clinical relevance (2009 review) | UK retail limit: 0.1% hydrogen peroxide |
| Peroxide mouth rinses | Some effect without clinical relevance (2009 review); no clinical studies (2020 review) | UK retail limit: 0.1% hydrogen peroxide |
| LED kits | Light not assessed by the reviews cited | UK retail limit: 0.1% hydrogen peroxide, in the gel |
A dash means the sources cited did not report on that point; retail limits count hydrogen peroxide present or released. If you notice sensitivity, changes in how your teeth look, or think you may have dental erosion, the Oral Health Foundation advises speaking to your dental team. NHS guidance on teeth whitening advises talking to your dentist about any side effects that bother you.
What actually whitens teeth?
Home bleaching products whitened teeth compared with placebo over 2 weeks to 6 months, a 2018 Cochrane review found, at low to very low certainty.
The review covered products from a dentist or over the counter at a range of concentrations, which may not reflect UK retail products. Sensitivity and oral irritation, the commonest side effects, were more frequent at higher concentrations but mild and transient. NHS guidance on teeth whitening advises talking to your dentist about any side effects that bother you. It also says using a kit from a dentist, or having it done at a dental surgery, is the safest way to have teeth whitening. The chemistry is on the page about how peroxide whitening works.
When should you speak to your dentist?
Speak to a dentist before whitening if you are unsure what is changing your tooth colour, and whenever a product leaves your teeth sensitive.
NHS guidance says the dentist should check your teeth and gums are healthy before you try teeth whitening, and that you can check whether someone is a registered dental professional on the GDC website. The page on teeth whitening regulation explains who may legally provide whitening.
Frequently asked questions
Does charcoal toothpaste absorb fluoride?
One 2020 laboratory study found two charcoal powders did not adsorb (bind) fluoride, though both were fluoride-free themselves. Laboratory-grade activated charcoal, tested as a control, did. NHS guidance says adults should use a toothpaste containing at least 1,350 parts per million (ppm) fluoride, so check the label of any charcoal product used for brushing.
Can you use baking soda toothpaste every day?
A 2017 review supports daily use. It called baking soda toothpaste a desirable alternative or additional measure for stain removal and whitening as part of daily oral hygiene. NHS guidance says to brush twice a day for about 2 minutes with fluoride toothpaste, so check the product contains fluoride.
Are whitening kits without hydrogen peroxide safer?
Not necessarily. A 2019 laboratory study of five products without hydrogen peroxide from two major British retailers found several etched enamel and two significantly reduced its hardness, while lightening varied: two lightened less than saline, two more than 10% carbamide peroxide. The authors said this suggests such products have the potential to damage enamel and lighten teeth.
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Teeth whitening at Deepcar Dental Care is provided by our dentists. Options include Enlighten and Boutique, both delivered as a take-home tray system.
Pages on whitening risks, enamel and the law are among the options in this section.
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