Not all hydroxyapatite is created equal.When choosing a toothpaste with hydroxyapatite, here’s what you need to know: Nano-Hydroxyapatite (nHA) – These ultra-tiny particles were originally developed by NASA to help astronauts prevent bone loss in space. While they absorb quickly, they’re impossible to source naturally and must be lab-synthesized. There’s also ongoing debate about their long-term safety and effectiveness in fully remineralizing enamel. Micro-Hydroxyapatite (mHA) – The form found naturally in teeth and bones! These larger particles work with your enamel, filling in microscopic cracks and strengthening teeth over time. Unlike nano, micro-hydroxyapatite has a well-established safety profile and is the form dentists trust for daily use. That’s why we only use micro-hydroxyapatite in our products!