By Aimee L

Until I was assigned this story, I didn’t realise that shampoos actually expired. I know this makes me sound super dumb, but the thought just never occurred to me, and now I can’t stop stressing about how many times I must have washed my hair with shampoo that was way past its expiration date (sigh).

If you think shampoo expiration dates are a myth (like I did), hear me out. When a shampoo is past its expiry date, it is no longer effective at doing what it’s supposed to do. This can result in your hair looking dull and dirty. Worse yet, the preservatives used are probably not effective anymore since the product is no longer stable, so it can cause itching or irritation to your scalp due to the shampoo’s chemical change. There could also be mould and bacterial growth, potentially triggering bacterial breakouts on the skin or even fungal diseases on the scalp.

On average, most shampoos last for 18 months after being opened, and will be marked with a PAO (period after opening) on the label. If the bottle has not been opened, it will expire three years from the date of purchase.

But since most of us probably don’t remember when we opened our shampoo, let alone when we actually purchased it, look out for certain visual signs that your shampoo might be past its expiry date. As a rule of thumb, your shampoo is probably past its expiry date if It doesn’t smell right, looks clumpy, has changed colour, or doesn’t lather as it once did.

Even though shampoo does not stay on the hair long, the ingredients can still penetrate the outer layers of skin on the scalp and this could cause harm to the follicles and irritate the skin, which may lead to an increase in hair loss.

To prevent wasting money and adding to the global waste problem, buy your shampoo only when you actually need it, and write down the date you open it with a permanent marker at the bottom of the bottle, so you know when it has expired.