Supermarket shelves are full of shampoos for dyed hair, claiming they help fight colour fade, but a Consumer NZ test has found you’d be better off using just water to retain your colour.
To discover which shampoo gave a longer lasting colour, Consumer tested 23 shampoos for coloured hair. After 12 washes, none performed better than an all-round shampoo or a baby shampoo. But the best solution was plain old water.
Consumer NZ CEO Sue Chetwin said Kiwis spent more than $3 million a year on shampoo for coloured hair. “Despite the marketing hype, we found washing your hair with water is the best option for freshly dyed hair.” After 12 washes it caused the least colour change, she said.
Even if you don’t want to use water alone, colour-care shampoos perform no better than the all-round shampoo or the baby shampoo. Paying more also does not deliver a better result. Whether you spend $10 per 100ml at a hair salon or less than $1.50 per 100ml at the supermarket, all colour-care shampoos are equivalent at preventing colour fade. Ms Chetwin said if you were fixated on buying a colour-care shampoo, buy on price.
Colour-care shampoos share a common ingredient, a UV filter, which slows down the rate sun bleaches hair dye. But even figuring in UV protection, none of the tested products appeared to offer any benefits compared to water.
Consumer asked several shampoo companies to provide evidence supporting their claims but none responded.
About our test:
- We sent 23 shampoos for coloured hair, one shampoo for all hair types and one baby shampoo for testing at an independent laboratory.
- The lab tested each shampoo on samples of blonde human hair that were dyed red with commercial dyes.
- Each sample was washed 12 times with each shampoo or water. Colour intensity was measured with a spectrophotometer before and after washing.
- To test the effect of UV exposure, each hair sample was exposed to the equivalent of six weeks’ summer daylight. The colour intensity was measured before and after exposure.