Published: September 2026 | Last updated: September 2026
No, you do not have to choose. Hydroxyapatite rebuilds enamel mineral and seals exposed dentine tubules, and a 2023 review of 44 trials found it cut sensitivity by 39.5% against placebo. Fluoride still prevents decay better than anything else. With the right fluoride salt, the two sit in the same tube at full strength.
Hydroxyapatite toothpaste has gone from a Japanese niche to one of the fastest growing categories on UK shelves, usually marketed as the fluoride free alternative. This guide explains what it does, how nano and biomimetic versions differ, which percentage to look for, and why “either or” is the wrong question.
What is hydroxyapatite and what does it do?
Hydroxyapatite is the calcium phosphate mineral that makes up around 97% of your enamel. In toothpaste it does two things: it bonds to the enamel surface and helps rebuild mineral lost to acid, and it plugs the exposed dentine tubules that cause cold sensitivity. A 2023 systematic review of 44 trials found it reduced sensitivity by 39.5% compared with placebo.
Because it is the same material as the tooth, it has a high affinity for enamel, and the EU’s scientific safety committee has assessed nano hydroxyapatite as safe for use in toothpaste within the inclusion levels it assessed.
Nano or biomimetic: does particle size matter?
Yes, and the two are complementary rather than competing.
- Nano hydroxyapatite particles are under 100 nanometres. That is small enough to travel deep into the dentine tubules and form a cement like plug, and to settle inside the microscopic scratches on the enamel surface. The crystals are rod shaped and align with the natural enamel structure. Over seven to ten days they grow and surface micro hardness increases, making enamel more acid resistant.
- Biomimetic hydroxyapatite is larger, around two microns, and less crystalline, with an amorphous, malleable structure matching the physiological composition of enamel. It does not penetrate the tubules. It settles into the nooks and micro lesions on the surface and forms a protective layer on top.
One works inside the tooth, the other on top of it. Very few UK toothpastes contain both.
What percentage of hydroxyapatite should I look for?
The clinical studies most often cited for nano hydroxyapatite used concentrations of around 10%.
Many toothpastes on the UK market do not state their percentage at all, and some contain only trace amounts for marketing purposes. And before you compare the labels that do state one, there is something almost nobody spells out. A percentage on a pack can refer to the raw material as it is supplied, which is often a solution, rather than to the active content itself. Those are two different numbers. Look for a brand that states the percentage and says what it refers to. If a brand does not state a percentage at all, treat that as a signal.
Is fluoride free better, or do you want both?
This is where most of the confusion sits. The two strengthen enamel differently. Hydroxyapatite adds new mineral. Fluoride changes the mineral already there, swapping into the enamel crystal to form fluorapatite, which resists acid better than natural hydroxyapatite. The NHS continues to recommend fluoride toothpaste for adults at 1350 to 1500 ppm, and it remains the best evidenced ingredient for preventing decay.
So why do so many hydroxyapatite toothpastes leave fluoride out? Partly positioning, because fluoride free sells, and partly chemistry. Fluoride in its common sodium fluoride form can react with the calcium in hydroxyapatite inside the tube, reducing both. The answer is a stable fluoride salt, sodium monofluorophosphate, which does not react with calcium and stays fully available in the mouth.
For sensitive teeth there is a third piece. Hydroxyapatite and fluoride both work on the tooth. Neither acts on the nerve, and a nerve calming active such as potassium nitrate is what reduces the pain signal itself.
Do dentists recommend hydroxyapatite toothpaste?
Increasingly yes, particularly for patients who cannot or prefer not to use fluoride, and for sensitivity. Most UK dentists still advise keeping fluoride in the routine, which is why formulas combining the two are the easiest to recommend. As always, if sensitivity is new or getting worse, get it checked before changing products.
A UK toothpaste with both, plus a nerve calming active
S3 Daily Sensitive Toothpaste, from S3 Sensitivity Science — backed by 20+ UK dentists — is one of the few UK formulas to combine:
- nano hydroxyapatite at 10% solution;
- biomimetic hydroxyapatite at 5% solution;
- fluoride at 1450 ppm, as sodium monofluorophosphate;
- potassium nitrate at 5%, for the nerve.
The hydroxyapatite is included at levels within those assessed as safe. The patent pending formula was developed by Majedeh Mazraei, a formulation scientist with more than 15 years in oral care, previously at GSK on Sensodyne and Aquafresh, over three years and 31 iterations.
In independent testing at the University of Reading, it deposited 8.1% calcium and 3.8% phosphorus by weight on the dentine surface, against 2.6% and 1.2% for Sensodyne Repair and Protect, with a calcium to phosphate ratio of 1.6, close to the 1.67 of pure hydroxyapatite. It achieved 100% dentine tubule coverage within 24 hours. In a consumer study of 52 existing sensitive toothpaste users, 88% felt an improvement within seven days. It is SLS free and vegan, and sells in the UK at £19.99 a tube or £14.99 on subscription.
Buying hydroxyapatite toothpaste in the UK: a checklist
- The percentage is stated, and the brand says whether it refers to the raw material as supplied or to the active content.
- Fluoride is included at 1350 to 1500 ppm, unless your dentist has told you otherwise.
- For sensitivity, there is also a nerve calming active, not only one that works on the tooth surface.
- SLS free, if your mouth is easily irritated.
- A clear ingredients list, with “Hydroxyapatite (nano)” named in the INCI.
Hydroxyapatite is a genuine step forward for enamel and sensitivity care. You just do not have to give up fluoride to get it.
Frequently asked questions
Is nano hydroxyapatite safe?
The EU’s scientific safety committee has assessed it as safe for use in toothpaste within the inclusion levels it assessed. Brands that use it should be formulating within those levels.
Can hydroxyapatite rebuild enamel?
It adds mineral back to the enamel surface and fills micro lesions, which is why it is described as remineralising. It is not a substitute for treatment of a cavity, which needs a dentist.
Does hydroxyapatite whiten teeth?
It can make teeth look brighter by filling surface lesions, so light reflects differently. That is an optical effect on the surface, not a bleaching agent.
Do I have to choose between fluoride and hydroxyapatite?
No. With a stable fluoride salt such as sodium monofluorophosphate, both can sit in the same formula at full strength.