Eight shampoo claims that don't quite stack upWhich? hair experts sort shampoo science from spin

20 April 2016

Shampoos in a laboratory

Shampoo claims should be backed by clear scientific evidence

Whether you're worried about your receding hairline, paranoid about parabens or just want to restore the sparkle to your crowning glory, there's a shampoo out there to match every possible hair concern.

With claims on packaging getting ever bolder, we asked a panel of hair experts to dish the dirt on whether manufacturers can back them up.

Below we reveal what our panel of a dermatologist, trichologist, chemist and marketing experts think you need to know before you choose your next bottle of shampoo.

You can read the full article 'What's really in your shampoo?', in the May 2016 issue of Which?. 

If you're not yet a subscriber, you can sign up for a £1 trial to receive the magazine. 

1. Makes hair healthier

Hair is dead, and no shampoo can bring it back to life. If you see a shampoo that promises smoothness, shine, moisturisation, hydration, nourishment or – as above – giving healthy-looking hair, it’s marketing talk for conditioning.

2. Reverses damage

It’s not possible to reverse hair damage by using a shampoo – it can only prevent further damage and make hair look healthier through conditioning.

3. Makes hair thicker

Thickening claims are often about putting something on the surface to improve the look and feel of the hair. The effect is is similar to when your hair appears thicker after a windy day at the seaside, as salt particles stick to your hair, creating spaces between hairs and giving it volume. Avoid heavy conditioning for a thicker effect.

4. Hidden extras

Look for the asterisks on the bottle. Our experts uncovered many products where small print indicated that the claim depended on more than one product from the same brand being used. In Pantene AgeDefy Shampoo's case, for example, this was three products totalling £22. The claims on Foltène Pharma shampoo - Thinning Hair for Men and Women meanwhile, depended on using it in conjunction with a treatment, bringing the total cost for both to £34.

5. Age defying

Look beyond meaningless marketing claims such as defying age, to find a shampoo that suits your hair type and gives a scent you like. Look twice at vaguer claims: our trichologist asked how Pantene AgeDefy can make hair look ‘ten years younger’ when hair actually only lasts around five to seven years.

Shampoo manufacturers aren’t always transparent with the data to back up their claims.


Richard Headland,
Which? Magazine Editor

6. Plant extracts 

Botanicals in shampoo include plant extracts such as red algae in Dove Regenerate Nourishment shampoo, aloe vera and coconut milk in Tresemme Botanique, and vitamins and amino acids (traditional ingredients include beer, eggs and protein). These are likely to be in low concentrations and – as part of a product designed to wash things away – unlikely to be effective.

7. Free-from parabens and preservatives

Look twice at products that trade on the benefit of more natural formulations or ‘free-from’ claims. Herbal Essences Clearly Naked 0% Moisture shampoo has no parabens (a preservative), silicones or dyes – but, like many products, it has the preservatives methylisothiazolinone and methylchloroisothiazolinone. This combination is a known skin sensitiser or allergenic.

8. Deceptive packaging

The bottles we assessed were a similar height, despite some being half the volume of others. Smaller products tended to be in boxes or tubes that tapered towards the top to ensure they were still ‘visually large’, so check the price per 100ml to compare products.

Shampoo claims

Our experts agreed that all shampoos will wash hair effectively. Apart from very cheap shampoos, the difference between average price and very expensive brands is likely to be in packaging and fragrance.

Be aware of the marketing ploys. Celebrity endorsements, apparent links to fashion and luxury such as 'London, Paris & New York' on the bottle, and distinctive product design can all have a heavy influence on us when we're shopping.

Which? Magazine editor Richard Headland says: 'Shampoos are loaded with a really wide range of ingredients and there are ever bolder claims for what they can do.  

It is simply not good enough to say their evidence is commercially sensitive and expect us to be satisfied with being told their products are safe and live up to claims on packaging, especially when they make substantial claims such as reducing hair loss.'

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