'I'm a hairdresser - my shampoo technique will transform your hair and make it healthier than ever'

While some may think that this is a "waste of money and product", the hair guru explained that the benefits of double cleansing are many.

According to the expert, it's especially effective for those with particular concerns such as hair growth and scalp health, or those who use a lot of products, such as dry shampoo.

She claimed that it's also effective for those who don't wash their hair too often, perhaps once or twice a week.

Mary told fellow hair enthusiasts: "Shampooing twice is going to transform your hair."

The hairdresser explained that double cleansing your locks is much like double cleansing the face.

When washing the face, the first cleanse is for removing any makeup, while the second properly cleans the skin.

Similarly, your first application of shampoo is for "lifting any build-up, dead skin, debris and oil off of the hair", while the second "actually cleanses the scalp".

Mary concluded that a clean scalp is essential for "optimum hair health".

As for conditioner, one hair enthusiast asked the expert how many times this should be applied per hair wash.

To this, she responded that conditioner should only be applied once before being rinsed out.

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In another video, Mary stressed the importance of incorporating this hair-washing practice into your routine. Indeed, she claimed it would give you the best hair of your life without spending a penny.

She also shared the brushing method that will give you your best hair ever by avoiding a "one-way ticket to breakage".

Rather than raking a brush through your hair, it's always best to start from the bottom of your strands and gently work upwards - particularly when your hair is wet.

In other hair care news, a celebrity hairstylist recently told GB News the two popular updo styles women should ditch to avoid breakage and damage.