Concentration is only half the story. What actually matters is whether an ingredient can integrate into your tooth, not just sit on top of it.
In skin care, bioavailability is a familiar idea: an active is only as good as the amount your body can actually absorb and use. Oral care has been slower to catch up, but the same principle applies, and it may matter even more here, because enamel isn't living tissue that heals itself. What you put on it either becomes part of its structure, or it doesn't.
This is where biomimicry comes in. A biomimetic ingredient is one built to match the exact structure of what it's replacing, so the body doesn't have to work to recognize or use it. Nano hydroxyapatite is the clearest example in oral care. It's not an additive borrowed from another industry. It's made to be chemically identical to the mineral that already makes up 97% of your enamel and 70% of your dentin. When it meets your tooth, it isn't coating a foreign substance onto the surface. It's returning the exact mineral your enamel is made of, in a form small enough to actually integrate.
Why particle size matters
Particle size is what makes that integration possible. At roughly 20 nanometres, rod shaped nano hydroxyapatite particles are small enough to move into the microscopic pores of enamel and the dentinal tubules beneath it, the tiny channels that connect to nerve endings. Fluoride, by comparison, works by forming a new compound, fluorapatite, on the outer surface. It's a real protective layer, but it stays at the surface. Nano hydroxyapatite is small enough to work from within.
For more on size and shape, read what rod shaped nano hydroxyapatite means.
Why 10%, and not more
Concentration still matters, but only up to a point, and this is where a lot of formulas lose the plot. A 2009 study testing 1%, 5%, 10% and 15% nano hydroxyapatite on demineralized enamel found microhardness recovery increased with concentration up to 10%, with no meaningful difference between 10% and 15%. A 2022 scoping review of the clinical research identified 10% as the optimal concentration. Past that point, you're not buying more efficacy. You're buying a bigger number on the label.
How we applied it
This is the thinking behind Bastét French Mint Toothpaste: 10% pure nano hydroxyapatite powder, the concentration the research actually supports, in the particle size and shape that lets your teeth use it. Alongside it, algin, a prebiotic from brown seaweed, works the same way, feeding your oral microbiome rather than sitting in the formula as filler. Every ingredient is there because your mouth can actually put it to use, not because it looks good on an ingredient list.
Bastét reading list: bioavailability and biomimetic minerals
- Nano Hydroxyapatite in the Remineralization of Early Dental Caries: A Scoping Review
- Effect of Nano Hydroxyapatite Concentration on Remineralization of Initial Enamel Lesion In Vitro
- Remineralization of Early Caries by a Nano Hydroxyapatite Dentifrice
Shop French Mint Toothpaste · Read the science behind 10% nHA
Written by Alexandra Baker, co-founder of Bastét.
