People are just discovering what the symbol on shampoo and conditioner means

It's clear TikTok is the gift that keeps on giving when it comes to providing us with all the knowledge that somehow passed us by in school.

One pearl of wisdom sees one woman shocked after finally discovering what the symbol on shampoo and conditioner means.

While the symbol is probably something we've never paid too much attention to, what with being overwhelmed by all the ingredients and information written on the label, it's fairly important to be aware of. Have a look:

In the clip, TikToker Denise - who goes by the handle @denisephx_official online - shared a video of a screengrab which featured a photo of a shampoo and conditioner bottle, with a circle around a symbol found on the reverse.

The screengrab explained: "How old were you when you found out... that this means how long you have to use that product from the date you break the seal before it's no longer considered a 'good product'."

Denise added: "Still blows my mind."

The symbol in question is a little tub with a number, followed by the letter M written inside - for example, '6M' or '12M'. This means that once opened, it's safe to use the product for that many months.

You may have noticed the little symbol on beauty products before and not realised, but it's certainly a handy guide to use to know when a product is past its best.

Some products also feature a best before date - which is represented by an hourglass with a date stamp - indicating when the product should be used by.

TikTok/@denisephx_official

This is used in products which have a shelf life of under 30 months.

To remember when you first opened the bottle or tub, it's a good idea to write a date on the product itself, to keep track of how many months it's been since opening.

And people couldn't believe they had never realised the symbol existed.

One person wrote on TikTok: "I was today's years old."

While another said: "What? For real?? Let me check."

And a third added: "Today years old and I was a hairdresser for 10 years smh."

Meanwhile a fourth commented: "Heading to my cupboard to look. I never even noticed that symbol before!"

And a fifth admitted: "Today years old!!!"

The symbol can be especially important on products such as suncream.

It’s important not to ignore the symbol as after the expiry date ends the active ingredients in the product begin to decompose and can become ineffective - which could result in some nasty sunburn!

Did you know about it?