Is your shampoo making your hair thinner? –

“To prove our theory that shampoos were depositing waxes and polymers on the scalp, we conducted a study,” says Dr Joe Cincotta, a leading cosmetic chemist who works alongside Federici. “Working with a group of women, we washed half of their head with a shampoo that was just designed to clean. Nothing else. On the other side, they used a conditioning shampoo. The study took microscopic pictures of the scalp where the hair emerged from the scalp, and it showed build-up and a physical block around the follicle.”

Dr Antonella Tosti, Professor of Clinical Dermatology at the University of Miami who oversaw the study, noticed that hair washed with shampoo containing silicone and conditioning and pearlising agents left ‘whitish deposits encircling the shaft and on the scalp at the hair emergency. Deposits were still present even after washing three days later, and even more so six days later’.

Put simply, this research found that any shampoo that claimed to perform an action other than just to simply clean (say, to create more volume, or de-frizz) was likely to have other ingredients in that would deposit product on the scalp during the cleansing process, and therefore have a cumulatively damaging effect on the health of the scalp.