Homemade Whitening Toothpaste: Recipe, Limits and Why Keep Fluoride

The simplest homemade whitening toothpaste is a paste of baking soda, a little 3% hydrogen peroxide and melted coconut oil, flavoured with mint. It can help lift surface stains from coffee, tea and wine, and many people like its clean, salty taste. What it cannot do is protect your teeth from decay, because it contains no fluoride. That one fact shapes how to use it sensibly: as an occasional polish alongside a regular fluoride toothpaste, not as a replacement for it.

Below is the recipe, what each ingredient really does, the claims that don't hold up, and a few practical cautions.

The recipe

This makes a small jar. Mix by volume, using a spoon as your "part".

• 6 parts baking soda (sodium bicarbonate)
• 1 part 3% hydrogen peroxide (the standard pharmacy strength)
• 1 part coconut oil, melted
• A pinch or a few drops of stevia, to soften the salty taste
• A few drops of food-grade spearmint or peppermint oil

Method: stir everything together until you get a smooth paste, then spoon it into a small glass jar with a lid. Use a clean spoon or spatula to put some on your brush rather than dipping the brush in, so the jar stays clean. Make small batches. Hydrogen peroxide slowly breaks down once mixed, and coconut oil hardens below about 24 °C, so the paste will firm up in a cold bathroom.

How to use it: brush gently, without scrubbing, then spit it out. Do not swallow it, and keep it away from young children, who are more likely to swallow toothpaste.

What each ingredient actually does

Baking soda

Baking soda is a mild abrasive. Abrasives are the main way any toothpaste removes surface stains: they polish away the film that coffee, tea and tobacco leave behind. Baking soda is gentler than many abrasives, which is why it has long been used in commercial toothpastes and tooth powders. Arm & Hammer, for example, sold a baking-soda tooth powder in the US until around 2000. It also neutralises acids for a short time, which some people find freshens the mouth.

Hydrogen peroxide

Peroxide is the same family of ingredient used in professional whitening gels, though those use much higher concentrations. At 3%, diluted further in a paste and in contact with teeth for only a minute or two, its whitening effect is modest. A baking soda and peroxide paste is nothing new: it was recommended for brushing as far back as around 1900.

Coconut oil, stevia and mint

Coconut oil mainly gives the paste a smoother texture and holds it together. Stevia and mint are there for taste. They make brushing more pleasant, which matters, because a paste you dislike is a paste you won't use.

Claims that don't hold up

Recipes like this one often come with big promises. Several are wrong or overstated:

• "Peroxide repairs cavities and hardens enamel." It does not. Peroxide can lighten stains, but it cannot rebuild a cavity or strengthen enamel. Once a cavity has formed, only a dentist can treat it. The ingredient with good evidence for protecting enamel is fluoride.
• "Coconut oil kills the bacteria that cause decay and gum disease." Lab studies show some antibacterial effects from compounds in coconut oil, and "oil pulling" has a following. But the evidence that it prevents cavities or gum disease in real life is weak. It is not a substitute for brushing and cleaning between your teeth.
• "Buy fluoride-free baking soda." Ordinary baking soda does not contain fluoride. There is no need to hunt for a special brand.
• "Fluoride is banned in Europe and Asia." This is not accurate. Fewer than 2% of Europeans get artificially fluoridated water, but Ireland, the UK and parts of Spain do fluoridate. Several countries, including Switzerland, Germany and France, use fluoridated salt instead. Fluoride toothpaste is sold and recommended across Europe.

Why fluoride still matters

Tooth decay fell sharply in the 20th century, and dental researchers credit regular use of fluoride toothpaste for much of that drop. A 2019 Cochrane review, which pools the results of many trials, found that toothpastes at standard fluoride strengths prevent decay, while concentrations below 1,000 parts per million (ppm) are unlikely to help.

The NHS advice is clear and simple:

• Adults should use a toothpaste with at least 1,350 ppm fluoride.
• Brush twice a day for about two minutes, including last thing at night.
• Spit out the excess after brushing, but don't rinse. Rinsing washes away the fluoride left on the teeth.
• Children of all ages can use family toothpaste of 1,350 to 1,500 ppm; for children 3 and under without decay, a children's paste with at least 1,000 ppm is fine.

Concerns about fluoride usually relate to swallowing too much of it, especially in young children, which can cause marks on developing teeth (fluorosis). Using the right amount of toothpaste and spitting it out deals with that. If you have specific worries about fluoride, talk to your dentist or doctor.

How to use a homemade paste safely

If you enjoy the taste and feel of a homemade paste, you don't have to give it up. A balanced approach looks like this:

• Keep fluoride as your main toothpaste. Use the homemade paste occasionally, for example a couple of times a week, and brush with a fluoride toothpaste the rest of the time.
• Be gentle. Any abrasive can wear enamel and exposed root surfaces if you scrub hard. Use a soft brush and light pressure.
• Watch for sensitivity. Peroxide can make teeth or gums sensitive. If you notice soreness, stop using it and speak to your dentist.
• Don't expect a colour change. Whitening toothpastes, homemade or bought, remove surface stains. They cannot change the natural shade of your teeth or fix discolouration inside the tooth. It typically takes a few weeks of regular use to notice a brighter look.
• Skip charcoal and harsh additives. Charcoal is popular in "natural" whitening products, but there is no good evidence for its safety or effect, and the American Dental Association does not recommend it.

Cost and the bigger picture

One appeal of this recipe is price. Baking soda and pharmacy peroxide are cheap, and a jar lasts a while. But a basic supermarket fluoride toothpaste is also inexpensive, and it does the one job that matters most: preventing decay. Treatment for a single cavity costs far more than years of toothpaste.

People have made their own tooth powders for thousands of years. Ancient Egyptian recipes used ash, pumice, crushed eggshells and myrrh; 19th-century British households used chalk, salt or even ground brick. Today's homemade pastes are much kinder to teeth than those. Used as a treat for the occasional extra polish, with fluoride doing the heavy lifting, a baking soda paste is a fun and harmless kitchen project.

Sources: NHS: How to keep your teeth clean; Wikipedia: Toothpaste (Cochrane 2019 review, abrasives, history); Wikipedia: Fluoridation by country; recipe originally shared by Organic Health.

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