Preserving Natural Mouthwash


I have made a homemade mouthwash with a pH of about 8.3-8.4. The mouthwash has a base of pure aloe juice along with thyme oil (0.025% thymol), clove oil (0.08% eugenol), and eucalyptus oil (0.1%). These oils are not dissolved in the aloe juice.

Will the essential oils be enough to preserve the mouthwash for several months? 

Must the oils be dissolved in the solution to have a preserving effect? 




  • DuncanDuncan Member, Professional Chemist
    I wouldn't risk it. Potassium Sorbate and Sodium Benzoate would be my fall back along with a suitably low pH (below 5) if my memory serves.
    The oils you mention do have a reputation for being antimicrobial but I'm not feeling that they will be enough
    UK based, Over 20 years in Toiletries, After a 5 year sabbatical doing cleaning products, back in the land of Personal Care
  • addition of a polyol (sorbitol, xylitol, erythritol, Glycerin) around 10% would aid in preservation by reducing water activity. Xylitol and Erythritol also have anticavity action and produce a cooling sensation in the mouth which would aid in masking the bitterness of some of the oils added. I would avoid lowering the pH below 5.5 as remineralization of tooth enamel cannot occur below 5.5.
  • MarkBroussardMarkBroussard Member, Professional Chemist

    Probably not Alex if the oils are not solubilized and are primarily sitting in a separate layer from the Aloe Vera base.  Try incorporating a solubilizer and some Xylitol (antibacterial and helps prevent cavities).  Lower the pH to 6.0 and as @Duncan mentioned ... Potassium Sorbate & Sodium Benzoate are commonly used in mouthwash products.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • Sugar alcohols only provide a cooling sensation in anhydrous products
    not those water based.

    IMO the best "natural" preservative for that formulation is ethyl alcohol
    being man made it ain't really natural, but at least it's fully plant derived.
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