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Alteration of taste perception
After using toothpaste, orange juice, and other fruit juices are known to have an unpleasant taste if consumed shortly afterwards. Sodium lauryl sulfate, used as a surfactant in toothpaste, alters taste perception. It can break down phospholipids that inhibit taste receptors for sweetness, giving food a bitter taste. In contrast, apples are known to taste more pleasant after using toothpaste.[69] Distinguishing between the hypotheses that the bitter taste of orange juice results from stannous fluoride or from sodium lauryl sulfate is still an unresolved issue and it is thought that the menthol added for flavor may also take part in the alteration of taste perception when binding to lingual cold receptors.[citation needed]

Whitening toothpastes
Many toothpastes make whitening claims. Some of these toothpastes contain peroxide, the same ingredient found in tooth-bleaching gels. The abrasive in these toothpastes, not the peroxide, removes the stains.[citation needed] Whitening toothpaste cannot alter the natural color of teeth or reverse discoloration by penetrating surface stains or decay. To remove surface stains, whitening toothpaste may include abrasives to gently polish the teeth or additives such as sodium tripolyphosphate to break down or dissolve stains. When used twice a day, whitening toothpaste typically takes two to four weeks to make teeth appear whiter. Whitening toothpaste is generally safe for daily use, but excessive use might damage tooth enamel. Teeth whitening gels represent an alternative.[70] A recent systematic review in 2017 concluded that nearly all dentifrices that are specifically formulated for tooth whitening were shown to have a beneficial effect in reducing extrinsic stains, irrespective of whether or not a chemical discoloration agent was added.[71] However, the whitening process can permanently reduce the strength of the teeth, as the process scrapes away a protective outer layer of enamel.[72]

Herbal and natural toothpastes
Companies such as Tom's of Maine, among others, manufacture natural and herbal toothpastes and market them to consumers who wish to avoid the artificial ingredients commonly found in regular toothpastes. Many herbal toothpastes do not contain fluoride or sodium lauryl sulfate. The ingredients found in natural toothpastes vary widely but often include baking soda, aloe, eucalyptus oil, myrrh, camomile, calendula, neem, toothbrush tree, plant extract (strawberry extract), and essential oils.[38] A systemic review in 2014 found insufficient evidence to determine whether the aloe vera herbal dentifrice can reduce plaque or improve gingival health, as the randomized studies were found to be flawed with a high risk of bias.[73]

According to a study by the Delhi Institute of Pharmaceutical Sciences and Research, many of the herbal toothpastes being sold in India were adulterated with nicotine.[74]

Charcoal has also been incorporated in toothpaste formulas; however, there is no evidence to determine its safety and effectiveness.[75] A 2020 systematic metareview of 24 comparative Randomised controlled trials, involving 1,597 adults aged 18 to 65, showed herbal toothpaste was superior over non-herbal toothpaste, but not to fluoride toothpaste.[38]

Government regulation
In the United States toothpaste is regulated by the U.S. Food and Drug Administration as a cosmetic, except for ingredients with a medical purpose, such as fluoride, which are regulated as drugs.[76] Drugs require scientific studies and FDA approval in order to be legally marketed in the United States, but cosmetic ingredients do not require pre-approval, except for color additives. The FDA does have labeling and requirements and bans certain ingredients.[77]
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Whitening toothpastes
Many toothpastes make whitening claims. Some of these toothpastes contain peroxide, the same ingredient found in tooth-bleaching gels. The abrasive in these toothpastes, not the peroxide, removes the stains.[citation needed] Whitening toothpaste cannot alter the natural color of teeth or reverse discoloration by penetrating surface stains or decay. To remove surface stains, whitening toothpaste may include abrasives to gently polish the teeth or additives such as sodium tripolyphosphate to break down or dissolve stains. When used twice a day, whitening toothpaste typically takes two to four weeks to make teeth appear whiter. Whitening toothpaste is generally safe for daily use, but excessive use might damage tooth enamel. Teeth whitening gels represent an alternative.[70] A recent systematic review in 2017 concluded that nearly all dentifrices that are specifically formulated for tooth whitening were shown to have a beneficial effect in reducing extrinsic stains, irrespective of whether or not a chemical discoloration agent was added.[71] However, the whitening process can permanently reduce the strength of the teeth, as the process scrapes away a protective outer layer of enamel.[72]