The Research Library
The science, in full.
Every ingredient in Peg Paste is there for a reason, and we think you should be able to read that reason for yourself. Below are the published studies, reviews and regulatory opinions behind our formulas, grouped by ingredient.
Last reviewed: October 2026.
Hydroxyapatite
Hydroxyapatite is the calcium phosphate mineral your enamel is mostly made of. It is the active ingredient in every Peg Paste formula. Every human trial below was designed to test whether hydroxyapatite toothpaste is as effective as fluoride toothpaste, and that is what they found.
Clinical trials and systematic reviews: tooth decay
- Clinical evidence of caries prevention by hydroxyapatite: an updated systematic review and meta-analysis — Pawinska et al., Journal of Dentistry, 2024. Pools five clinical trials: hydroxyapatite outperformed placebo and performed comparably to fluoride.
- The role of hydroxyapatite-based, fluoride-free toothpastes on the prevention and the remineralization of initial caries lesions: a systematic review and meta-analysis — Chatzidimitriou et al., Journal of Dentistry, 2025. Independent review (no manufacturer authors): no significant difference between hydroxyapatite and fluoride toothpastes in new or progressing lesions.
- Caries-preventing effect of a hydroxyapatite toothpaste in adults: an 18-month double-blinded randomized clinical trial — Paszynska et al., Frontiers in Public Health, 2023. 194 adults, 10% hydroxyapatite vs 1450 ppm fluoride: hydroxyapatite was non-inferior. Microcrystalline HA.
- Impact of a toothpaste with microcrystalline hydroxyapatite on the occurrence of early childhood caries: a 1-year randomized clinical trial — Paszynska et al., Scientific Reports, 2021. 207 young children: hydroxyapatite was non-inferior to fluoride. Microcrystalline HA.
- Impact of a non-fluoridated microcrystalline hydroxyapatite dentifrice on enamel caries progression in highly caries-susceptible orthodontic patients: a randomized, controlled 6-month trial — Journal of Investigative and Clinical Dentistry, 2019. Microcrystalline HA.
- Biomimetic hydroxyapatite and caries prevention: a systematic review and meta-analysis — Canadian Journal of Dental Hygiene, 2021.
- The use of hydroxyapatite toothpaste to prevent dental caries — Odontology, 2022. Review.
- Improving oral health with fluoride-free calcium-phosphate-based biomimetic toothpastes: an update of the clinical evidence — Biomimetics, 2023. Review.
- A comparative efficacy of a hydroxyapatite and a fluoride toothpaste for prevention and remineralization of dental caries in children — Amaechi et al., BDJ Open, 2019.
- Effect of apatite-containing dentifrices on dental caries in school children — Journal of Dental Health, 1989. The early Japanese school trial that started the field.
- Effect of nano-hydroxyapatite and ozone on approximal initial caries: a randomized clinical trial — Scientific Reports, 2020. Nano-HA.
- Comparison of the effects of toothpastes containing nanohydroxyapatite and fluoride on white spot lesions in orthodontic patients: a randomized clinical trial — Dental Research Journal, 2020. Nano-HA.
- Hydroxyapatite as remineralization agent for children's dental care — Frontiers in Dental Medicine, 2022. Review.
Remineralisation: in-situ and laboratory studies
- Remineralization of molar incisor hypomineralization (MIH) with a hydroxyapatite toothpaste: an in-situ study — Amaechi et al., BDJ Open, 2022. In situ, 15 participants, 14 days, MIH-affected enamel.
- Remineralization of early caries by a nano-hydroxyapatite dentifrice — Najibfard et al., 2011. In situ, nano-HA.
- Anti-caries evaluation of a nano-hydroxyapatite dental lotion for use after toothbrushing: an in situ study — Journal of Dentistry, 2021. In situ, nano-HA.
- Bionic effects of nano hydroxyapatite dentifrice on demineralised surface of enamel post orthodontic debonding: in-vivo split mouth study — Progress in Orthodontics, 2021. Nano-HA.
- Enamel remineralization and repair results of biomimetic hydroxyapatite toothpaste on deciduous teeth: an effective option to fluoride toothpaste — Journal of Nanobiotechnology, 2019. Baby teeth.
- Comparison of hydroxyapatite and fluoride oral care gels for remineralization of initial caries: a pH-cycling study— 2020. Laboratory.
- Enamel and dentine remineralization by nano-hydroxyapatite toothpastes — Journal of Dentistry, 2011. Laboratory, nano-HA.
- Ca2+ release and buffering effects of synthetic hydroxyapatite following bacterial acid challenge — BMC Oral Health, 2020. Laboratory. How hydroxyapatite releases calcium and buffers acid.
- Effect of nano-hydroxyapatite concentration on remineralization of initial enamel lesion in vitro — Biomedical Materials, 2009. Laboratory, nano-HA.
- Remineralization potential of nano-hydroxyapatite on initial enamel lesions: an in vitro study — Caries Research, 2011. Laboratory, nano-HA.
- Comparison of nano-hydroxyapatite and sodium fluoride mouthrinse for remineralization of incipient carious lesions — Laboratory, nano-HA.
- Effect of hydroxyapatite nanoparticles on enamel remineralization and estimation of fissure sealant bond strength to remineralized tooth surfaces: an in vitro study — BMC Oral Health, 2019. Laboratory, nano-HA.
Reviews and background
- Hydroxyapatite in oral care products — a review — Materials, 2021.
- Overview on adjunct ingredients used in hydroxyapatite-based oral care products — Biomimetics, 2022.
- Advanced non-fluoride approaches to dental enamel remineralization: the next level in enamel repair management— 2021.
- Cariogenic biofilms: development, properties, and biomimetic preventive agents — Dentistry Journal, 2021.
- Biomimetic action of zinc hydroxyapatite on remineralization of enamel and dentin: a review — Biomimetics, 2023.
- Nanomaterials in preventive dentistry — Nature Nanotechnology, 2010.
- Nano-hydroxyapatite and its applications in preventive, restorative and regenerative dentistry: a review of literature— 2014.
- Reconsidering remineralization strategies to include nanoparticle hydroxyapatite — 2013.
Particle size and safety: micro vs nano
- SCCS Scientific Opinion on Hydroxyapatite (nano) — Submission IV — European Commission Scientific Committee on Consumer Safety, final opinion published July 2025. Concludes rod-shaped nano-hydroxyapatite is safe up to 29.5% in toothpaste and 10% in mouthwash. Micro-hydroxyapatite sits outside the EU nanomaterial definition (1–100 nm) and was not the subject of this review.
- Hydroxyapatite nano and microparticles: correlation of particle properties with cytotoxicity and biostability — Biomaterials, 2009. Laboratory. Compares nano and micro particles directly.
- Cytotoxicity of hydroxyapatite nanoparticles is shape and cell dependent — Archives of Toxicology, 2012. Laboratory.
- Evaluation of cytotoxic effects and oxidative stress with hydroxyapatite dispersions of different physicochemical properties in rat NR8383 cells and primary macrophages — Toxicology in Vitro, 2009. Laboratory.
- Review of potential health risks associated with nanoscopic calcium phosphate — Acta Biomaterialia, 2018.
- Nano-hydroxyapatite in oral care cosmetics: characterization and cytotoxicity assessment — Scientific Reports, 2019.
- Can nano-hydroxyapatite permeate the oral mucosa? A histological study using three-dimensional tissue models — 2019.
- Nanohydroxyapatite in dentistry: a comprehensive review — Saudi Dental Journal, 2023.
- On the application of calcium phosphate micro- and nanoparticles as food additive — Nanomaterials, 2022.
- Fate of hydroxyapatite nanoparticles during dynamic in vitro gastrointestinal digestion: the impact of milk as a matrix — 2021. Laboratory. What happens to hydroxyapatite if swallowed.
Xylitol
Xylitol is a plant-derived, sugar-free sweetener (ours is from corn). Unlike sugar, the bacteria in your mouth cannot ferment it into acid. It is used in Peg Paste at around 1–2%.
- Xylitol-containing products for preventing dental caries in children and adults — Riley et al., Cochrane Database of Systematic Reviews, 2015. The most rigorous review of xylitol to date; it rates most of the evidence as low quality.
- Xylitol in preventing dental caries: a systematic review and meta-analyses — Janakiram et al., Journal of Natural Science, Biology and Medicine, 2017.
- Effects of xylitol and erythritol consumption on mutans streptococci and the oral microbiota: a systematic review— Acta Odontologica Scandinavica, 2020.
- Effects of xylitol chewing gum and candies on the accumulation of dental plaque: a systematic review — Clinical Oral Investigations, 2022.
- Is xylitol effective in the prevention of dental caries? A systematic review — 2024.
Chicory root oligosaccharides (prebiotic fibre)
A natural prebiotic fibre extracted from chicory root. We include it as a prebiotic fibre; we make no claim about specific oral health outcomes, because the published oral research is still early.
- Expert consensus document: the International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics — Gibson et al., Nature Reviews Gastroenterology & Hepatology, 2017. The accepted scientific definition of a prebiotic.
Sodium lauroyl sarcosinate
Our gentle, low-foam cleanser. It is made from sarcosine (an amino acid derivative) and lauric acid, and it is not a sulphate — which is why Peg Paste is sulphate-free.
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Amended safety assessment of fatty acyl sarcosines and sarcosinate salts as used in cosmetics — Fiume et al., Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2021. Concludes these ingredients are safe as used in cosmetics when formulated to be non-irritating.
All of the above
- An introduction to toothpaste — its purpose, history and ingredients — Lippert, Monographs in Oral Science, 2013. What each class of toothpaste ingredient (abrasives, humectants, binders, flavours) is for.
Hydrated silica (Coconut)
- Amended safety assessment of synthetically manufactured amorphous silica and hydrated silica as used in cosmetics — Burnett et al., Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2025. Safe as used in cosmetics when formulated to be non-irritating.
Glycerin
- Safety assessment of glycerin as used in cosmetics — Becker et al., Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2019.
Acacia senegal gum, xanthan gum
- Re-evaluation of acacia gum (E 414) as a food additive — European Food Safety Authority, EFSA Journal, 2017. No safety concern at reported uses; no numerical acceptable daily intake needed.
- Safety assessment of microbial polysaccharide gums as used in cosmetics — Fiume et al., Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2016. Includes xanthan gum; safe in present practices of use.
Menthol and peppermint oil
- Final report on the safety assessment of Mentha piperita (peppermint) oil, leaf extract, leaf and leaf water — Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2001.
Clove oil (Sacred Clove)
- Clove (Syzygium aromaticum): a precious spice — Cortés-Rojas et al., Asian Pacific Journal of Tropical Biomedicine, 2014. Review of clove's composition and traditional uses.
Salvadora persica (miswak) stem extract (Sacred Clove)
- Knowledge, awareness, and practice towards the use of Salvadora persica L. (miswak) chewing stick: a scoping review — Scoping review of how miswak is used around the world.
Zinc glycinate (Enamel Shield+)
- Zinc in the mouth, its interactions with dental enamel and possible effects on caries: a review of the literature — Lynch, International Dental Journal, 2011.
Glyceryl caprylate, caprate and laurate (preservation system)
- Safety assessment of monoglyceryl monoesters as used in cosmetics — Fiume et al., Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2020. Covers 44 glycerin–fatty acid esters; safe in present practices of use.
Background reading: how tooth decay and the oral microbiome work
Not about any one ingredient: the foundations for understanding the studies above.
- Early childhood caries: epidemiology, aetiology, and prevention — 2018.
- Sugars and dental caries: evidence for setting a recommended threshold for intake — Advances in Nutrition.
- Contemporary perspective on plaque control — British Dental Journal, 2012.
- The International Caries Detection and Assessment System (ICDAS): an integrated system for measuring dental caries — Community Dentistry and Oral Epidemiology, 2007. How the trials above measure decay.
- The effect of brushing time and dentifrice on dental plaque removal in vivo — 2009.
- Toothbrushing and flossing behaviour in young adults — a video observation — Clinical Oral Investigations, 2014.
- Influence of the amount of toothpaste on cleaning efficacy: an in vitro study — 2022.
- The human oral microbiome — Dewhirst et al., Journal of Bacteriology, 2010.
- Defining the healthy "core microbiome" of oral microbial communities — Zaura et al., BMC Microbiology, 2009.
- Oral microbiome and health — 2019.
