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Cleaning abrasives

Sodium bicarbonate

Also listed as baking soda, bicarbonate of soda, sodium hydrogen carbonate

Baking soda: a very low-abrasion toothpaste cleaner that lifts stain and slightly reduces plaque and gum bleeding. In deodorants it neutralises odour but often irritates.

Moderate evidenceTypical strength: From a few percent up to over 60% in toothpaste; varies widely in deodorants

What it is

In toothpaste and mouthwash, baking soda is a soft abrasive (pure baking soda has an RDA of about 7, far below silica) that still removes surface stain well, and it buffers plaque acids. It tastes salty, which is why some pastes are mostly baking soda and others use a little.

In deodorants it neutralises the acidic compounds that smell. It is alkaline, and a common reason 'natural' deodorants cause red, itchy or darkened underarms.

How strong is the evidence?

Moderate evidence

A 2019 systematic review found baking soda pastes remove more plaque in single-brushing tests, only partly confirmed in longer trials, and slightly reduce gum bleeding. A network meta-analysis ranked it among the weaker toothpaste additives for gingivitis. Stain-removal evidence is good but comes from narrative reviews. The deodorant irritation point is from clinical experience, not trials.

What it's used for, checked

Removes surface stain with low wear

Holds up

Effective stain removal despite very low abrasivity.

Reduces plaque and gum bleeding

Mixed

Clear in single-use tests; small or inconsistent in longer trials.

Prevents decay on its own

Unproven

Choose a baking soda paste that also contains fluoride.

Neutralises underarm odour

Holds up

Works chemically, but alkalinity irritates many people's skin.

Works well with

  • sodium-fluoride

Who should be careful

  • Do not brush with neat kitchen baking soda as a substitute for toothpaste: you lose the fluoride.
  • If a baking soda deodorant causes redness, itching or darkening, stop using it; the rash usually settles, and a bicarbonate-free product avoids it.
  • People on strict sodium restriction need not worry about toothpaste: it is spat out.

The studies

Every citation is checked against its PubMed record.

  1. The efficacy of baking soda dentifrice in controlling plaque and gingivitis: A systematic review.
    Valkenburg C, Kashmour Y, Dao A, Van der Weijden GA, Slot DE · Int J Dent Hyg · 2019 · Systematic review / meta-analysis

    21 publications: baking soda paste removed more plaque in single-brushing studies, only partly confirmed in longer studies; gum bleeding fell slightly versus control pastes, with no difference in gingival index. Moderate risk of bias, high heterogeneity.

  2. Stain removal and whitening by baking soda dentifrice: A review of literature.
    Li Y · J Am Dent Assoc · 2017 · Narrative review

    In lab and clinical studies, baking soda toothpastes removed extrinsic stain effectively and safely despite relatively low abrasivity, in several studies better than more abrasive non-baking-soda pastes.

  3. Efficacy of adjunctive anti-plaque chemical agents in managing gingivitis: A systematic review and network meta-analyses.
    Figuero E, Herrera D, Tobias A, et al. · J Clin Periodontol · 2019 · Network meta-analysis

    53 six-month trials. Among rinses, essential oils, chlorhexidine (0.10% or more) and cetylpyridinium chloride (above 0.05%) had the largest effects on gingivitis, with essential oils ranking highest; active toothpastes differed little from each other, with baking soda among the weakest.