The NOBS (No Bad Stuff) toothpaste tablets are going viral thanks to their main ingredient of nano-hydroxyapatite, a fluoride-free alternative. As health concerns around fluoride and its presence in public drinking water continue to swirl, nano-hydroxyapatite toothpastes are becoming increasingly popular. You’ve likely seen them on store shelves or in ads from companies like Boka and Davids, marketed as fluoride-free alternatives for your toothbrush that claim to whiten teeth, repair enamel and prevent cavities.
“As ingredient labels shift toward cleaner, fluoride-free formulas, one compound is taking center stage in modern oral care: nano-hydroxyapatite,” Dr. Pia Lieb, DDS, cosmetic dentist and clinical assistant professor emerita at NYU College of Dentistry, explains. According to dentists, if you’re considering replacing your fluoride toothpaste with a nano-hydroxyapatite alternative like the now-viral NOBS, you should know the following potential benefits and side effects.
What is nano-hydroxyapatite?
“Nano-hydroxyapatite is a synthetic calcium phosphate compound that’s used in some oral care products, including toothpastes,” explains Dr. Ada Cooper, consumer advisor and spokesperson for the American Dental Association, says. “[It] has a structure that is similar to hydroxyapatite found in enamel, and nHAP gets incorporated into the tooth structure preferentially in demineralized areas.”
Nano-hydroxyapatite is also abbreviated as n-HA and n-HAp.
Dr. Royce Lai of King Village Dental adds that this is technically a two-part question, since “hydroxyapatite has been around for decades and has been studied for at least 20 years.” Newer and less studied, nano-hydroxyapatite is a version of hydroxyapatite with small, rod-shaped particles.
“Hydroxyapatite is natural. It is a type of calcium that makes up bones and teeth,” says Lai. “Nano-hydroxyapatite relates to the particle size. These are between 20 and 80 nanometers and are much smaller than the hydroxyapatite tubules that are a part of your teeth.”
According to Dr. Daniela Eversgerd, a cosmetic dentist and the founder of Allure Dental, nano-hydroxyapatite was developed by NASA in the 1970s for astronauts dealing with bone and enamel loss during long periods of space travel. Since the early 1990s, it has been approved for oral care products in Japan.
Nano-hydroxyapatite toothpaste benefits
“Nano-hydroxyapatite doesn’t just protect your teeth — it helps rebuild them,” says Dr. Catrise Austin, a cosmetic dentist, author of Gum Health Made Simple and host of the Let’s Talk Smiles podcast. She lists the following as potential nano-hydroxyapatite benefits:
- Enamel remineralization
- Tooth sensitivity relief
- Reduced bacterial adhesion
- Whitening and gloss enhancement
“n-HA can actually fill microscopic cracks and help reverse or arrest early cavities,” adds dentist Dr. Sandip Sachar.
Austin cites a 2019 study that found a 10% hydroxyapatite toothpaste is equivalent or non-inferior to fluoride toothpaste for preventing and remineralizing dental cavities (or caries) in children.
When it comes to teeth sensitivity, Lai cites a 2014 study concluding that 15% nano-hydroxyapatite helped sensitive teeth. “The particle size could get into space and work better than larger particles in micro-hydroxyapatite or fluoride,” he explains. “The conclusion was that nano-hydroxyapatite could significantly reduce tooth sensitivity to hot and cold in two to four weeks of use.”
Referencing an 18-month 2023 clinical trial finding that a 10% n-HAp toothpaste protected adult teeth from new cavities as well as a standard 1,450-ppm fluoride paste, Dr. Christopher Tolmie, DDS, MBA, of PDS Health, states, “By patching enamel and calming swollen gums, nano-hydroxyapatite may cut off a hidden spark of chronic inflammation linked to heart disease and diabetes.”
Since nano-hydroxyapatite toothpastes are fluoride free, Dr. Yenile Y. Pinto, DDS, functional and biomimetic dentist and founder of Deering Dental, adds, “It’s also been shown to reduce sensitivity and strengthen the enamel surface without the risk of fluorosis.” Fluorosis occurs when you get too much fluoride as a child, causing white or brown spots on the teeth. The CDC reports that fluorosis typically doesn’t affect tooth function and isn’t painful.
A 2020 systematic review of 32 studies concluded that “Nano-HA is a relatively novel material with outstanding physical, chemical, mechanical and biological properties that makes it suitable for multiple interventions. It outperformed most of the classic materials used in implantology and surgery, but it should be further investigated for bone engineering and caries prevention therapy.”
Ultimately, providing a 2021 review and 2022 scoping review, Cooper concludes, “Although there is some evidence that alternative ingredients, such as [nano] hydroxyapatite, prevent tooth decay by acting as a remineralizing or anti-cavity agent, the studies are preliminary. The only anti-cavity agent recognized by the Food and Drug Administration in its over-the-counter monograph is fluoride, a naturally occurring chemical.”
Cooper adds that all toothpastes with the ADA Seal of Acceptance contain fluoride. The administration specifically recommends brushing your teeth twice a day with fluoride toothpaste and regularly visiting your dentist.
Nano-hydroxyapatite toothpaste side effects
“According to a [2021] narrative review from Odontology, the official journal of the Society of the Nippon Dental University, so far, there have been no reports of adverse dental or systemic effects of HAP-containing toothpastes because HAP has an excellent biocompatibility,” states Cooper.
According to Austin, the concern with nano-hydroxyapatite is that, because it’s made of nanoparticles, some worry about how much might get absorbed into the body if regularly swallowed. “The European Commission’s Scientific Committee raised concerns due to the lack of long-term safety data on ingestion, particularly in children,” she says. This has led to temporary nano-hydroxyapatite restrictions (not a full-on banning) in Europe.
The European Scientific Committee deems nHA safe in toothpaste up to 29.5% and up to 10% in mouthwash, per Tolmie. However, he states, “Regulators still bar it from breath-spray products to avoid lung exposure, so stick to pastes and rinses.”
Key concerns around nano-hydroxyapatite, according to Lieb, are:
- Potential ingestion and systemic absorption, especially in nano form
- Lack of long-term studies in humans on the cumulative effects
- Unknown impact of inhalation from aerosol products (not toothpaste)
In terms of systemic absorption, Sachar specifies, “Because nano-hydroxyapatite particles are similar in composition to bone mineral, there has been some theoretical concern that if absorbed systemically, they could potentially contribute to unwanted calcifications in soft tissues (like blood vessels or kidneys).” However, she states that this is speculative and not supported by any current clinical evidence.
Is nano-hydroxyapatite toothpaste only effective at 10%?
“Most clinical formulations of nHA range from 5%-15%, with 10% emerging as the benchmark concentration in several Japanese and European studies,” answers Lieb. “This concentration has demonstrated reliable enamel restoration while maintaining product stability and usability.”
However, she states that newer formulations are experimenting with lower concentrations and enhanced delivery systems (such as encapsulation or synergistic minerals), which may improve efficacy at reduced levels. “The effectiveness isn’t just about percentage, it’s also about particle quality and how it’s delivered to the tooth surface,” she explains.
Tolmie adds, “Effective repair starts as low as 5% and plateaus around 10-15%. Several studies show that 5% n-HAp can mend enamel dings, divots and dents in the teeth, with benefits leveling off somewhere between 10% and 15%. One review even noted that 5% sometimes beats 10% because fewer particles clump, making them easier to slip into enamel defects; hence, most US brands sit comfortably in the 5-10% sweet spot.”