The best approach to take care of your teeth, according to dentists, is to brush twice a day. However, the cost of maintaining a healthy oral hygiene routine might vary significantly depending on the month.

According to recent studies, the price of a toothpaste tube can vary over the year, often by twice as much. Other well-known health products, like Gillette razors, might quadruple in price depending on when they are purchased.

Comparable goods from the top three brands that were offered for at least 42 weeks of the year, from March 2023 to February 2024, were examined by the consumer advocacy group Which?

With toothpaste, at one end of the price scale, Colgate’s Max White Ultimate Radiance (75ml) cost from £11 up to £25.20 in Waitrose. Asda and Boots commonly priced the product at £12.

A standard product, Colgate’s Max White Expert Whitening Toothpaste, ranged between £2.50 and £5 in a year.

Ele Clark, the retail editor at Which?, said: “Retailers constantly change products’ prices based on demand, seasonality, agreements with manufacturers, and what their competitors are doing.

“Keep an eye on the prices of products you buy regularly and stock up when the price is low – or ask yourself if it’s really essential to have your preferred brand and consider switching to a cheaper product that can do just as good a job.”

Researchers also discovered a variation in the cost of mouthwash across shops. An example was Colgate’s Max White Expert Whitening (500ml) which regularly sold at £2.50 and £5 at all big supermarkets during the year. Meanwhile, another mouthwash, Listerine Advanced Defence Gum Crisp Mint (500ml) cost between £3 and £6 at Boots.

Which? took a snapshot price for each product at the same time each week over the year, excluding multi-buy offers and loyalty pricing.

Consumers often had to pay more for razors, particularly some Gillette products. The Gillette Labs Razor with Exfoliating Bar cost £22.49 at Morrisons when it was full price but was frequently reduced to half that amount: £11.25.

Allergy tablets emerged as another popular health product with significant price variations.

A packet of 30 Piriteze Hayfever and Allergy Relief Tablets at Waitrose was reduced from £11.50 to £8 between May and July 2023 and then it cost £11.55. At Boots, the same product was £10.55 from March to July 2023, then rising to £11.55.

The Which? investigation showed Asda was the cheapest supermarket overall for health products, based on a comparison of 107 like-for-like health and personal care goods that were available at Asda, Boots, Morrisons, Ocado, Sainsbury’s, Superdrug, Tesco, and Waitrose throughout the year. Aldi and Lidl stock fewer brands so were not included.

Which? approached all of the retailers for comment. Boots, Superdrug and Waitrose said that they aimed to offer the best value to customers through a range of deals. The other supermarkets did not comment.