I started using solid shampoo bars about nine or ten months ago. I noticed how often I was buying plastic bottles of shampoo and it seemed like an easy switch. It’s taken a bit of trial and error (and plenty of research!) but I’m now pretty knowledgeable about shampoo bars so I wanted to share what I’ve learnt in the hopes it’ll help others switch to a more sustainable shampoo.

This post turned out way longer than I’d expected (over 3200 words), as I wanted to be thorough, so I’ve included lots of subheadings to make it easy to find the information you’re looking for.

What is a shampoo bar?

A shampoo bar is basically what it says on the tin. It’s shampoo compressed into a solid bar form. There are two main varieties: the first is really just a bar of soap, made through the traditional saponification process; the second is more like a conventional shampoo, using surfactants like sodium coco sulfate to clean hair.

I used the first kind for about eight months, but after moving to our house I was finding that the water was so hard that it was really hard to work up a good lather and the bars were leaving gunk on my hair, no matter how long I rinsed for. I’ve recently purchased this bar, which uses sodium coco sulfate, and though I’ve only used it once so far, I think it’s safe to say I’m a convert. My scalp is happy, my hair is soft, and there’s no gunk.

Why use shampoo bars

Sustainability

The big reason I switched to using shampoo bars is for the environmental impact. Conventional liquid shampoo comes in a big plastic bottle, and the first ingredient on the ingredient list? Water. This means that in the process of getting the shampoo from the manufacturer to me, extra fuel is being used just to transport water, a substance I have got plenty of in my shower already.

Because a shampoo bar is solid, it’s more concentrated and will last longer than a similar weight of liquid shampoo. Likewise, because it’s not liquid it doesn’t need to be transported in unsustainable plastic bottles or even heavier glass bottles; the shampoo bars I get are packaged either in thin boxboard or paper sleeves.

Fragrance

I’ve never liked the artificial fragrances of a lot of conventional shampoos. They smell almost sickly sweet, and can often be overpowering. In contrast, shampoo bars are typically scented with essential oils (but do read the ingredients!), meaning they have a light, more natural scent. It also means that you know exactly what’s in it; there’s no nebulous ‘fragrance’ item on the ingredient list.

Better for your hair and scalp

Most conventional shampoos use harsh detergents like sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). These work well to remove grease from hair – sometimes too well. If your hair feels dry and brittle, or your scalp gets itchy and flaky, then you may well benefit from switching to a gentler surfactant. Sometimes, even, if you feel like a greaseball and must double-lather every day to get your hair clean, you can find that if you use a gentler surfactant your hair stays clean for longer, as you’re not stripping so much of the natural oil that your scalp overproduces it to compensate.

Conventional products also often have long lists of ingredients, including fragrance and preservatives. Preservatives are not bad. Preservatives are in fact pretty fantastic. Without them, your liquid shampoo becomes a breeding ground for bacteria and other nasties. However, the more ingredients there are in a product, the greater chance that there will be one that doesn’t play nicely with your skin or hair. If, like me, you have sensitive skin, then using products with fewer ingredients makes it easier to choose ones that don’t contain anything your skin doesn’t like. 

For instance, the conventional shampoo I was using before trying shampoo bars has twenty-one ingredients, one of which is ‘fragrance’ (which means it’s likely to be multiple ingredients for a fragrance blend). The shampoo bar I use now has thirteen, two of which are the essential oils of neroli and sweet orange. That means the conventional shampoo has 1.5x as many potential irritants for my sensitive skin. 

I’m not saying this to make you worry about all the possible dangers lurking in your shower right now. Cosmetic ingredients DO undergo testing (though of course this varies from country to country) and I don’t want you stressing about every little ingredient in your deodorant or washing up liquid.

However, if you’ve spent your life trying to find the holy grail shampoo that cleans your hair without turning your scalp into an itchy, flaky mess, then a gentler shampoo bar may well be what you need.

Things to consider when choosing a shampoo bar

There are a few things to consider when switching to a shampoo bar, and how much weight you give any of them depends on your own reasons for choosing shampoo bars.

Soap or synthetic?

As I mentioned earlier, there are two main kinds of shampoo bars. There are traditional soap-based bars, made by saponifying fat with lye, and bars using synthetic detergents, or syndets. 

For the purposes of choosing which shampoo bar to use, syndet bars can be broken down further based on what kind of detergent is used. Lush, for instance, uses sodium lauryl sulfate (SLS), a harsh surfactant, while others use gentler detergents like sodium coco sulfate (SCS) or sulfate-free surfactants.

So which should you use?

If you have soft water and a sensitive scalp that is easily irritated by conventional shampoos, then a soap-based bar would be a good choice. It’s the most natural option, so if that’s important to you then they might be a good starting point. I highly recommend Chagrin Valley products if you go this route; although their shampoo bars ultimately didn’t work for my water, I use a number of their other products (face soap, body/hand soap, deodorant), they’re transparent about their ingredients, and their customer service is excellent.

One thing to note with soap-based shampoo bars is that they are not pH-balanced. For some people this isn’t an issue, but for others it can lead to an itchy and flaky scalp. If you’ve used traditional soaps (even something like Dr Bronner’s) on your body or face before without irritation then you’re more likely to find a soap-based bar works well on your scalp.

If you have hard water, then I would suggest trying syndet shampoo bars. We have very hard water here (320ppm after using our crappy water softener), and I found the soap-based bars were leaving a scummy film on my hair. I’m sure the cut-off point varies from person to person, and I’ve read about people in London (around 275ppm) successfully using saponified shampoo bars, so if your water is moderately hard and you’d like to try a soap-based bar first then by all means go ahead. Just be aware that it may be more likely to cause issues if your water is harder. 

Likewise, if you know that using pH-balanced products is important for your skin, then I would suggest choosing a syndet bar that’s pH-balanced, as it is impossible to pH balance a traditional soap.

I would also recommend a syndet bar if you’re really not sure about this whole natural haircare thing, but you really want to stop filling your shower with plastic bottles. A syndet shampoo bar with a surfactant like SCS is going to give you a comparable experience to using conventional shampoo and is least likely to have an uncomfortable adjustment period.

One thing I would advise is to steer away from Lush bars, unless you have a condition like seborrheic dermatitis that requires harsh cleansing to keep it under control. For many people, SLS is just too harsh a detergent, and can lead to an itchy, flaky scalp, over-production of oil, and dry, straw-like hair. Even if you feel like you absolutely have to shampoo every day with a conventional shampoo in order to keep the oil at bay, you may in fact be over-washing your hair and causing your scalp to produce more oil. Switching to a gentler surfactant will, after a few weeks of adjustment, cause your scalp to produce less oil and, therefore, need washed less frequently.

Other ingredients

Once you’ve decided if you want to use a soap-based bar or a syndet shampoo bar, it’s also worth considering the other ingredients. Generally speaking, I like to choose products that are scented with essential oils instead of that nebulous ‘fragrance’. I have eczema and asthma, so if a particular scent or ingredient is bothering me, it’s much easier to isolate the problem if the ingredient list for a product lists every single ingredient, instead of the catch-all term ‘fragrance’.

And, generally, I just like to know exactly what’s in the product that I’m putting on my skin, same as I like to know exactly what’s in the food I put in my body.

If this isn’t a big deal to you, and your primary reason for switching to shampoo bars is solely environmental, then you may not care how the product is scented and happily choose a bar that cites ‘fragrance’ as an ingredient, and I’m not here to judge. But for people who have had issues with conventional products, sometimes it’s as simple as choosing a more naturally scented product.

Who you’re buying from

Once you’ve narrowed down the kind of bar you want, you’ll want to make sure that acquiring the bar is as eco-friendly as possible. Look for a company that uses plastic-free recyclable/compostable packaging – even better if you can buy it in a local store you can walk or bus to!

The companies that I’ve referenced here in this post are local-ish to me, in that although I order online, they’re on the same continent and I have the products shipped via the traditional postal service – there’s no overnight couriering from Australia. I actually mucked up buying my Unwrapped Life shampoo bar, as after the order was shipped I realised there was a store a few miles up the road on the tram line that sells their products. Still, I try as much as possible to choose more sustainable shipping options and to be mindful of how far the products are travelling.

Do you need an acid rinse?

If you’re buying a soap-based bar, you may see recommendations to use an acid rinse, often diluted vinegar/ACV, after rinsing out your shampoo. This is because the shampoo is alkaline, and your scalp and hair tend to prefer a more acidic environment. An acid rinse will help smooth the cuticle, reducing the risk of tangles and increasing shine, and can also keep your scalp from getting itchy.

Some people can get away with using a soap-based shampoo bar and no acid rinse, especially with softer water as soft water tends to be more acidic than hard water. My recommendation would be to try both. A popular option is a splash of apple cider vinegar in a pint of water, though do be aware that on very light hair it can add darker/redder tones. Personally, I prefer a pinch of citric acid in a litre of water as my hair takes a very long time to dry and I don’t like walking around smelling like a chip shop for hours!

If you’re using a syndet bar, there’s no need for an acid rinse, as it’s already pH-balanced.

But what about conditioning?

So you’re ready to ditch the plastic bottle for shampoo, but there’s another problem bottle in your shower – conditioner. I’m planning on doing a post on alternatives to bottled conditioner, but for now I want to just say that every step you make towards a zero-waste lifestyle counts; even if you’re still using bottled conditioner with your shampoo bar you’ve still halved the number of plastic bottles you’re using for your hair, and that’s a good start.

If you’re using a soap-based shampoo bar, you may read about using a vinegar rinse as ‘conditioner’. It’s not a conditioner in the technical sense, but it may be enough, depending on your own hair. A vinegar rinse helps the cuticle lie flat, which not only reduces tangles but can also help keep the water (ie moisture) in your hair where you want it. 

If you’re using a syndet shampoo bar, you may find the company you buy from sells solid conditioner bars, like this one. One thing to look out for with solid conditioner is that you don’t want one that’s just a bunch of oils and butters – those don’t moisturise and will leave your hair feeling greasy and gross. I haven’t tried solid conditioner bars myself (though Jessica Rose Williams has, if you’d like to check her post out for more info), so I can’t tell you how to use them or if there’s a learning curve, but if you find you definitely need conditioner then you may want to give one of these a go. 

You may also find that using a gentler shampoo means you don’t need conditioner. This really is something that depends a lot on hair type; I have fine, straight hair with very little damage or processing, and I grew my hair past my hips never using conditioner at all, and it stayed soft and silky and tangle-free. Others with curlier hair, drier scalps, or damage from bleach or heat styling may need conditioner to keep their hair from tangling.

At any rate, if you need to use conditioner with your shampoo bar then don’t feel overly guilty about still using bottled conditioner. Developing a more sustainable lifestyle isn’t about going from a mainstream lifestyle to zero-waste living in a day; it’s taking one small step after another to reduce harm.

How to use a shampoo bar

Using a bar to wash your hair might sound weird at first if you’re used to liquid shampoo, but it’s easy, I promise. For most of human history bar soap was the way everyone washed their hair (when they washed it, admittedly), so it’s not some strange new idea. Just like with liquid shampoo, you want to lather up on your scalp and rinse. 

There’s two ways to create lather on your hair with a shampoo bar. You can either rub the bar directly on the scalp (I like to rub from hairline to nape like I’m combing my hair), or you can rub it between your hands and create lather that way, then rub the lather on your scalp. If you have thick hair, like I do, you may want to separate your hair into sections and rub the bar across them to make sure you’re lathering on the whole scalp. If you do this, you’ll also want to make sure you’re sectioning your hair out to rinse, to get all the shampoo off your individual strands.

You may have read that you don’t need lather to cleanse. While this may be true in the most technical sense (the lather isn’t what’s cleaning your hair), from a practical standpoint the lather is important for making sure it rinses clean; the air bubbles in the lather help separate the hair strands so they all get rinsed. This is especially true with soap-based shampoo bars, as it’s easy for them to leave a waxy coating on your hair if they don’t rinse out fully. I actually found when I tried to use soap-based bars in my hard water I had to wash twice, as the first time there wasn’t enough lather to rinse clean.

Be sure to store your shampoo bar in a well-drained soap dish (not a travel tin) and out of the shower spray. Allowing it to dry off between uses will increase its lifespan. 

Troubleshooting common shampoo bar issues

If you’re using a syndet shampoo bar, there shouldn’t be any real transition period or any troubleshooting to do, as the detergents should be very like the ones you’re currently using in conventional shampoo. 

If you’re using a soap-based shampoo bar, however, you might have some issues transitioning to it, as it’s quite a different experience to using a conventional shampoo. There are some common issues that are often easily fixed, so you’ll want to try these out before giving up.

Help! My hair is still greasy when it dries

There are two possible culprits here. One is that the shampoo isn’t cleansing enough, or that because it’s gentler you need to shampoo twice rather than once like you may have done with traditional shampoo. The other is that it’s not rinsing well enough.

You can often tell which it is based on where the grease is. If it’s an all-over oiliness, then you may need to lather up a second time, especially if you have harder water. You want to lather enough times to get a rich, fluffy lather all over your scalp.

If the greasiness is concentrated at certain parts of your head (such as below the crown and at the nape), then it’s more likely a problem with rinsing. If this is your issue, then you probably need to be more vigilant about sectioning your hair to rinse. If you have a detachable shower head, that’s also great for getting into all the nooks and crannies. You can also try washing your hair in the bath instead, if you have one. It’s much easier to rinse your hair evenly when you dunk it under the water in the bath, instead of trying to move your head about and separate your hair under the shower head. 

Hair is tangly and feels like straw

Because soap-based bars are alkaline, they lift the cuticle of your hair slightly. Think of the cuticle like the shingles of a roof. On healthy hair, these shingles lie flat, trapping moisture in the hair shaft and increasing shine. On unhealthy hair, these shingles are raised, catching on each other and causing tangles. 

Alkalis, like the lather created from soap bars, also lift the shingles of your cuticle, which can cause tangling and hair that just feels dry and unpleasant. This is more likely to happen with harder water, as it tends to be more alkaline than soft water. 

For many people, this can be solved by following up the shampoo with an acid rinse. After rinsing out your shampoo, pour over a solution of either dilute vinegar (a splash of vinegar in a jug of water) or citric acid (just a pinch in a litre works well for me), making sure you cover all your hair. You can either leave this in as a final rinse, or you can leave it on while you finish your shower and rinse it out at the end.

The weak acid flattens the cuticle and helps increase shine and prevent tangling.

My hair feels fine, but my brush is covered in grey gunk

This was my problem. My hair was all right, for the most part (once I figured out how to build lather in my hard water, anyway!). But there was this horrible scummy grey gunk on my comb every time I combed my hair. Unfortunately, I think this was essentially soap scum because my water is so hard, so for me the only solution was to switch to a syndet shampoo bar. I’m not about to throw out the soap-based bars, though – that would hardly be the eco-friendly solution. They still work great for shaving, so I’ll slowly use them up that way.

A final note

I hope I’ve helped de-mystify solid shampoo bars a little for you. With so many options (and everyone claiming theirs is the best!) it can be hard to figure out what you should choose, especially when all you want to do is make your haircare routine a little more sustainable. I’ve tried to provide enough information here to help you get started, as well as to make sure that your switch is as simple as possible.

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