Which? has urged shoppers not to "fall for the hype" during the Black Friday and Cyber Monday sales this year.

The major shopping days fall on Friday, November 25 and Monday, November 28.

The brand, which promotes informed consumer choices, has encouraged us not to buy without carefully examining whether items were really worth buying and that the “discounted” price offered a genuine saving.

The advice follows similar guidance from the MoneySavingExpert founder Martin Lewis who shared a 'memo' with his followers as the sales approach.

Impartial Reporter: Black Friday falls on Friday, November 25. (Canva)Black Friday falls on Friday, November 25. (Canva) (Image: Canva)

Which? urges Black Friday shoppers to not "fall for the hype"

The watchdog also revealed in a new study that one in seven Black Friday deals offers a genuine discount.

The research also suggested that the vast majority of promotions are actually cheaper or at least the same price in the six months before the sales event.

Which? analysed 214 Black Friday deals across seven major retailers last year including Amazon, AO, Argos, Currys, John Lewis, Richer Sounds and Very.

It looked at their prices every day in the six months before and after last year’s event on November 26.

183 or 86% were cheaper or the same as their Black Friday price in the six months before the event, the watchdog found.

Meanwhile, 209 (98%) were actually cheaper or the same price at other times of the year.

Most notably though, none was cheaper on Black Friday alone.

Although there were some deals to be had, Which? concluded that the genuine discounts were “often few and far between”.

Impartial Reporter: Cyber Monday takes place on Monday, November 28 this year. ( Canva)Cyber Monday takes place on Monday, November 28 this year. ( Canva) (Image: Canva)

There were worse culprits than others with Amazon and Very being named as the “worst retailers overall for dubious discounts”.

More than 70% of the products included in Which?’s analysis were cheaper at other times of the year compared to their Black Friday price.

Which? retail editor Reena Sewraz said: “Our research shows that finding a good deal on Black Friday is like looking for a needle in a haystack.

“It’s rarely the cheapest time to shop and you’ll probably find the things you want are the same price or cheaper as we head towards Christmas, the New Year and beyond.

“Retailers are not blind to the extra pressures on people’s finances this year and will be keen to use Black Friday to attract people looking to get the most for their money, so we should still expect some deals. Our advice is to take the time to do some research if you want to find a genuine bargain."

An Amazon spokesman said: “We seek to offer our customers great value thanks to low prices all year round as well as a number of fantastic seasonal deals events.

READ MORE: Martin Lewis issues Black Friday shopping 'memo' to UK shoppers

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“Our Black Friday sale offers thousands of deals from every category across the site at a time of year when we know saving money is important to our customers.”

Meanwhile, Richer Sounds chief executive Julie Abraham said: “Black Friday is now an event that takes up the majority of November. For their research, Which? used just the single day of Black Friday as the basis for their price comparison.

"Our Black Friday Event prices are available for customers from early November, so it’s inevitable that some prices compared will have been the same in the days preceding Black Friday.

“With regards to pricing after Black Friday, we can only set prices for Black Friday with the information we have at that time. Afterwards, manufacturers may have excess stock to shift, or other determining factors in the market means that some prices stay low and we’re always delighted to be able to offer our customers an extended opportunity to get a saving.”