Eco and travel-friendly, solid shampoos offer a range of benefits, but how do they scrub up? We put them to the test

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Switching to a shampoo bar is one of the easiest ways to get on the plastic-free beauty bandwagon. Compact and convenient, shampoo bars are one to watch with environmental concerns increasingly playing on our minds, but are shampoo bars good for your hair? As with liquid shampoos, it depends on what's in your shampoo bar.

As well as being  plastic packaging-free , other common qualities of shampoo bars include a more natural focus when it comes to their ingredient lists and greater longevity compared to liquid shampoo (in fact, one claims to last 80-100 washes and do the job of three 250ml bottles of shampoo). Furthermore, because of their smaller size, more can fit into the lorries that transport them to reduce your carbon footprint even further. Although many shampoo bars have mostly natural ingredients, watch out for foaming agent SLS. This is an ingredient that some people find harsh and avoid in their bottled shampoo, so it’s worth checking the ingredients if you're sensitive to it.

Certain to appeal to natural beauty fans and the eco and space-conscious, how do shampoo bars compare to liquid shampoo?

How do you use a shampoo bar?

Some brands recommend rubbing the bar between your hands first while others advise applying it directly to the scalp instead.

Kieran Tudor, who is the creative director for natural haircare brand Centred recommends applying the bar directly onto wet hair and rubbing it in. "Shampoos are great for using like this because you can direct the bar to exactly where you need it most," he says. "With liquid shampoo, we tend to focus it on the top of our hair and sometimes miss the underneath, particularly if you've got thick hair."

Do you use a conditioner after a shampoo bar?

Yes - in this way it's no different to bottled shampoo. If using conditioner in a plastic bottle feels counterintuitive, Lush has a selection of conditioner bars too.

How do you look after a shampoo bar?

In much the same way you look after a bar of soap - keep it out of the way of direct water. "Store your shampoo bar somewhere it will air dry," advises Kieran. "After you've finished with it, rinse the suds off it, place it into a dish with a draining system and allow it to air dry." Some brands, including natural haircare brand WeDo sell containers for your shampoo bar to live in .

Who is a shampoo bar for?

Kieran recommends shampoo bars for most hair types, from fine to thick, normal to oily, but notes that if you've got very dry hair, or chemically treated hair, it's better to stick to a shampoo formulated for colour-treated hair.

If you’re interested in giving one a try, here are the shampoo bars team GTG rate.

Shampoo bar reviews

Centred Altered State Solid Shampoo, £20

GTG's editorial director Victoria said she’d swap her bottled shampoo for this. It’s SLS-free, with a gentler foaming agent (sodium cocoyl isethionate) from coconuts and with a lovely fresh smell that lasts up to 60 washes. It lathers up really well and comes in Altered State Fragrance Free  version too, £20. Unlike using other shampoo bars my hair didn’t feel greasy the next day.

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Eco Warrior Dry Hair Shampoo Bar Argan and Coconut Oil Blend, £4.50

Free from SLS, sulphates, silicones and alcohol, this bar is designed with dry hair in mind so was perfect for GTG's commercial projects manager Catherine to test. She has bleached hair that tangles easily so this bar was really put through its paces. It has quite a soapy smell, with a subtle hint of coconut. Being SLS free, this didn't deliver as much foam as Catherine's usual liquid shampoos. It was easy to lather on the top of her head but less so on the lengths. It washed out easily without any residue left behind and after following with conditioner did as good a job as any liquid shampoo at cleaning.

Eco Warrier recommends applying this straight to your hair rather than sudding up in your hands first. The brand says it can't say exactly how many washes the shampoo bar is supposed to last, as it's dependent on how much hair you have and how many times a week you wash it. "Despite this, we can reassure you that it will definitely outlive any 500ml bottle of shampoo alternative," it writes on its website.

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Klorane Mango Shampoo Bar for Dry Hair, £7.33

GTG's social media and design manager Jemma tried this on her afro-textured hair. "I really enjoyed using this," she told us. "Unlike other shampoo bars I’ve used in the past this didn’t leave my hair feeling dry, tangly or straw-like. Instead, it felt surprisingly nourished and soft and remained so after washing. It did give a good lather though not as much as my bottled shampoo would. It did take a while to build some suds up however it did the job well in the end."

Klorane says this one bar is the equivalent to two 200ml bottles of shampoo and should be lathered in your hands before applying to your hair. It's sulfate-free and vegan.

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We Do No Plastic Shampoo, £14.95

Loved by Fearne Cotton, this shampoo bar is sulfate-free and vegan and lasts up to 80 washes. Massage directly onto wet hair until it forms and then distribute through your hair. Hair-loving ingredients include castor oil and shea butter. "While Fearne Cotton loves this bar and it really walks the sustainability walk (for every product they sell they Work with Plastic Blank to collect eight ocean waster plastic bottles), it felt hard to lather on both our testers' hair types (curly and afro)," says GTG's editorial director Victoria Woodhall. "It underlines the fact that your hair type has a lot to do with whether a particular bar works for you - it's worth persisting til you find your fit. We love the bamboo soap dish  though as there’s nothing worse than forgetting which soggy soap bar is yours when the name wears off."

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Davines Dede Naked Shampoo Bar, £14

GTG's digital writer Melanie tried this and had her reservations about trying a shampoo bar, expecting it to be drying to her colour-treated hair, but felt reassured using one from Italian brand Davines, known for high-end formulas. It certainly smelt luxe, with the same scent and formula used in the brand's Dede range, which happens to be the best-seller and is for all hair types. It created as much of a lather as any liquid shampoo, using sodium cocoyl isethionate for the rich foam and should last 33 washes. It's silicone and sulphate free. "Rather than applying this straight onto my head, which I knew would tangle my hair, I lathered it extensively in my hands and then applied to the lengths, ending up with a lot of forthy suds which made it feel the same as using a normal shampoo," Melanie says. "It washed out fine, I followed with conditioner and my hair felt no different to normal once I'd dried it."

Davines sells a dedicated  tin , £7,  to keep your shampoo bar in, with little holes in the bottom to allow it to dry properly.

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Nuddy Ultra Volume Blow Dry Bar, £8.95

This peach-scented shampoo bar promises to last twice as long as your standard bottle of shampoo; around 80 washes to be precise. Formulated for all hair types, it’s infused with natural coconut oil and argan oil so leaves you with soft, weightless, bouncy hair without any waxy residue. Plus, it earns brownie points for being vegan-friendly, plastic-free, cruelty-free, SLS free and made in the U.K. Jemma tried this one too (she has been busy!) and was impressed by how lightweight it left her hair. It should be lathered in your hands and then applied to your hair too. Nuddy also has a shine enhancing shampoo bar and a thickening one, if volume isn't what you're wishing for.

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Garnier Ultimate Blends Delicate Oat Softening Shampoo Bar for Sensitive Scalp and Fragile Hair, £7.99

If you're familiar with Garnier's Delicate Oat liquid shampoo and conditioner, this smells the same, if a little more subtle. A warm comforting and soothing scent. Tested by GTG's digital writer Melanie, this creates a soft foam (using sodium cocoyl isethionate) and is teardrop shaped so fits comfortably in your hand. One bar lasts up to two months and it rinses out quickly, which can save up to a bottle of water with every wash. It's made with 94 per cent plant-based ingredients and is soap and silicone-free  – Holly Willoughby said of the bar "I love the scent and it leaves my hair feeling super silky" – if it's good enough for her!

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Faith In Nature's Coconut and Shea Butter Shampoo Bar, £3.86

User reviews say this is so good that there's no need for a conditioner afterwards because the hair is left so soft and frizz-free. They also comment on how long it lasts, but the brand doesn't say how many washes to expect from the bar. It's free-from parabens and SLS plus it's made from 100 per cent natural fragrance; it leaves the hair a bit sticky-feeling when it's still wet, but once dry it feels silky smooth. The brand also does a Dragonfruit fragrance and a Lavender and Geranium scent too. GTG's Jemma tried this bar out and was pleasantly surprised with how nourished her afro hair felt and impressed that it didn’t leave her with the squeaky clean soap feeling often associated with bars.

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Biovene Damage Control Coconut and Keratin Solid Shampoo , £5.99

A combination of coconut oil, macadamia oil, keratin, beeswax and shea butter work together in this purple shampoo bar to rescue damaged, dull-looking hair. Reconstructive keratin revives and strengthens your locks while promoting healthy length and density. The collection also features an argan oil and mint bar to combat hair fall, a biotin and apple cider shampoo bar for moisture and volume, a citrus shampoo bar to clarify and a nourishing bar to smooth and soften hair. One bar should last as long as one and a half bottles of liquid shampoo

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Lush Seanik Shampoo Bar, £8

Formulated with volume in mind, this bright blue hair soap contains seaweed to soften, lemon oil to cleanse and fine sea salt for texture. Lush was way ahead of its time when it came to shampoo bars and as we said, now sells a plethora of them for different needs; New  is specially formulated for thin or fine hair, while Soak and Float  can help to treat sore, dry or irritated scalps. Other additions to the range include Montalbano , which is loaded with popping candy for the ultimate morning pick-me-up and Jason and The Argan Oil , which contains 23 per cent less SLS to help prevent fade on colour-treated hair. One bar says it will the job of three 250g bottles of liquid shampoo

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Only Curls Cleansing Shampoo Bar, £12

Curly hair expert Only Curls has launched its first ever shampoo bar, free from sulphates, silicones and drying alcohols, designed specifically to hydrate and nourish curls which are notoriously dryer than straight hair (oils from the scalp take longer to travel down the coil, so ends a naturally more frazzled). This bar has avocado and kukui nut oils for nourishing and foams up using a gentle sulphate free surfactant.

If you're familiar with the signature Only Curls scent, this has the same citrus and coconut fragrance. The bar lathers up well and feels creamy in the hair and rinses out exactly the same as liquid shampoo. To use you rub the bar between your hands then massage the lather into hair and scalp.

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