The FDA Says To Toss Old Shampoo And Conditioner

As with most products, you can tell when a shampoo or conditioner goes “bad.” There’s usually a change in the smell, consistency, or both. The Food and Drug Administration does not require manufacturers of shampoo and conditioner to print expiration dates onto packaging, but it does recommend that consumers ditch their bottles once they’ve been open for about 18 months (earlier if you notice something weird).
Not only are the products less effective at cleaning and conditioning at this age, but they can also spread bacteria onto your scalp, which opens the door for infection.
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