Moving to solid shampoo and conditioner bars is a plastic-free swap that many people try, but not all are prepared for what this entails - solid products are quite different to the bottled stuff we're used to. If you want to make the switch to shampoo and conditioner bars, that's great. You will reduce plastic and may save money, but don't throw away your empty shampoo bottles quite yet!
In my experience, there are two categories of shampoo bars - I call them 'hair soap' and 'solid shampoo'. You'll be able to tell the difference by looking at the first ingredient on the label. Hair soap has oil as its first ingredient (sodium olivate, sodium cocoate, etc.) while solid shampoo will list a surfactant (sodium cocoyl Isethionate, sodium coco sulphate, sodium lauryl sulfate).
I class bars from Alter/Native, Friendly Soap and Scrub Shop UK (formerly Hearts & Homespun) as hair soap, and those by Zero Waste Path, Ethique, and Lush as solid shampoos.
(At the time of writing, Refills on the Road stocks solid hair products from Scrub Shop UK, Friendly Soap, Zero Waste Path, and Goap. Our aim is to provide a range of products sourced as locally as possible to suit different needs and budgets.)
If you try a hair soap, you will likely experience a 'transition period' while your scalp adjusts to two major changes. First, many liquid shampoos contain sodium lauryl sulfate which, while creating a nice foamy lather, is also very drying (not to mention derived from palm oil). For years, we've been sold shampoo that strips our hair of dirt and oil paired with a matching conditioner that restores the stripped moisture - usually by coating our hair in silicone. When you stop stripping your hair's natural oils away, your scalp will need time to rebalance its oil production.
Second, cold process soap is pH 9-10 (alkaline), while our hair and skin is in the pH 4.5-5 range (acidic). So when you start using soap on your hair you throw off its pH balance. This is why vinegar rinses are often recommended to 'condition' the hair - the acid lowers the pH balance of your hair back to a level your body is happier with.
The length of transition you'll experience is different for everyone. Some people get on with them straight away, while others take weeks to adjust and some never do (like me!). In the year I have been selling shampoo bars I have generally observed that people who like soap-style bars have shorter, straighter hair that is neither particularly thick nor thin in texture. People who have reported not liking these bars have longer, thicker, or curlier hair.
Hair soap pros: usually less expensive, may last longer, can be used as 'all in one' bars to wash hair and body.
Hair soap cons: may require transition period and/or vinegar rinses, don't differentiate for hair types, may strip colour
If you opt for a solid shampoo bar, you can avoid a transition period but there are other issues to consider; primarily: how your hair reacts to sulfates. You might have noticed that I mentioned sodium lauryl sulfate and sodium coco sulfate as possible first ingredients in these bars. Some people find they react to sulfates and they are also not recommended for curly hair!
There is good news: the first ingredient in 2-in-1 bars from Zero Waste Path and Ethique bars is sodium cocoyl isethionate. This is a surfactant derived from the fatty acids in coconut oil, it is sulfate-free, and very gentle on the skin and scalp.
This type of shampoo bar is typically more expensive than the hair soap variety. Lush's 'Honey I Washed My Hair' bar, at 55g for £8 comes to 15p per gram of product, but lists sodium lauryl sulfate as its first ingredient. Zero Waste Path's 40g bars for £7.50 cost 19p per gram, but are made in Cambridge UK. Ethique's bars at 110g for £12.99 (12p per gram) are the least expensive but are made in New Zealand and have a lot of miles on them by the time they reach your shower.
Solid shampoo pros: no transition period, no need for vinegar rinses, some have special formulations for different hair types and are gentler on artificial colour
Solid shampoo cons: usually more expensive, may contain sulfates
With conditioner bars, whether one brand or another works for your hair will really depend on what you want out of it. Like shampoo bars, the key is in looking at the ingredients list. The three bars I have compared all contain cocoa butter, Behentrimonium Methosulfate (BTMS), and essential oils; the number and type of other ingredients vary.
The Cosy Cottage Nourishing Conditioner Roundel (15g for £2.50) has cocoa butter as the first ingredient and was like a tiny little hockey puck - it was hard and unyielding in my hands, even in a scalding hot shower. Its small size made it hard to handle and I kept dropping it because it was so tiny. I rubbed it on my hair but couldn't feel any product transfer. At a cost of 17p per gram of product, it was the most expensive bar I tried, and the worst performing.
The Alter/Native conditioner bar (90g for £5.45) - also listing cocoa butter as the first ingredient - was a little bit better. It softened and something came off onto my hair, but it didn't make my hair feel silky or detangled. I gave it the benefit of the doubt and told myself the cocoa butter added moisture to my hair, if nothing else. At 6p per gram of product, it was the least expensive conditioner bar I tried but I felt very ambivalent about its performance.
The bar I liked best, by a Cheshire company called Goap (32g for £4.25), really surprised me after my experiences with Cosy Cottage and Alter/Native. The bar is round, but being larger it was easy to keep hold of. I rubbed it directly on the ends of my hair, and when I rinsed it out my hair felt silky - just as if I had used a liquid conditioner on it. At 13p per gram of product, it was mid-range on cost but I felt it was the best performing.
Friendly Soap, based in Yorkshire, includes directions on their website for how to convert one of their conditioner bars into liquid conditioner by melting it into hot water. Comparable in size and price to the Alter/Native bars, this seems an interesting option at first, but they advise you to use the product up within 7 to 10 days. £5.50 every 10 days for conditioner is extremely expensive and I personally wouldn't recommend going down that path. However, if the bar works for you in solid form, it is very good value for money.
Using Shampoo and Conditioner Bars
I am often asked how one uses a shampoo bar. There are a couple of options.. One is to rub the bar on wet hair in a few places to transfer some of the soap to the hair, then lather. Another is to lather the bar in your hands and then work the suds into your hair. In both cases, rinse well.
Different makes of shampoo bar will lather to different degrees. The Lush bars lather a lot, because they contain Soldium Lauryl Sulfate (SLS). SLS is a surfactant found in your 'traditional' liquid shampoo - it creates that nice lather, but it also strips your hair of its natural oils (and SLS is derived from palm oil).
The formulation of your shampoo bar - which will largely depend on the ethical and environmental goals of its maker - may mean it lathers very little by comparison. You may not like the first shampoo bar you try, the same way you prefer some brands of liquid shampoo to others. If the first one doesn't work out, try another one before giving up. However, some people decide they just don't get on with shampoo bars. Prepare yourself for a bit of experimentation.
Conditioner bars are pretty much a 'rub it on your hair' product across the board. They do not lather, though some get a little bit melty so you can rub some off onto your fingers and then massage it into your hair.
Conditioning with vinegar
Dilute a couple tablespoons of vinegar in a jug of warm water, and pour it over your hair at the start of your shower, working it to the roots. Leave it while you do all the rest of your bits, and rinse it out at the end. This will make a big difference to the texture and feel of your hair.
I decided to be clever and pre-mix vinegar rinse to avoid having a glass vinegar bottle next to the shower. What I forgot was that it wouldn't be the same temperature as my nice hot shower and dumping cold vinegar water on my head wasn't pleasant when I wasn't expecting it!
Making your shampoo bar last
The good thing about shampoo and conditioner bars is they should last longer than bottled shampoo (though this depends on the size of bottle you were using before the switch!). But remember they are a soap and will dissolve into a pile of mush if you leave them in water.
Store the bars in a way that keeps them as dry as possible in between uses. If you have a soap tin, stand the bars on end to keep the surface area that may sit near water to a minimum. Another option is to use a soap dish that has drainage holes, and keep the bar at the far end of your shower to keep it away from the spray.
Shampoo and conditioner bars may work well for a lot of people, but they aren't for everyone. Don't feel bad if you don't get on with them. You can reduce plastics in other ways, such as by finding a zero-waste shop nearby that refills bottles with liquid shampoo.
Two brands on the market offer suppliers a full circular refill system: Cole and Company (made in Wales) and Miniml (made in Yorkshire). Other suppliers such as Suma and Faith in Nature make claims that empty bottles returned to them will be 'reused in their supply chain' (no one knows exactly what this means) but at the time of this writing neither company is fully circular and are still creating high levels of demand for virgin plastics.