A couple of weeks ago I wrote about how to switch to using solid shampoo bars instead of bottled shampoo. Unlike bottled shampoo, solid bars typically come in sustainable packaging, and because they’re not primarily composed of water, they don’t weigh as much for shipping purposes.

But most of us have two bottles for haircare in the shower (if not more). Replacing your liquid shampoo with a shampoo bar is a great start, and can halve the number of plastic bottles you’re using each year, but that still leaves conditioner. For many people, the thought of washing their hair without conditioning afterwards is horrifying. Visions of tangled tresses and matted messes come to mind. 

Just as there’s another option for shampoo, however, there’s also another option for conditioner – quite a few, actually. The most obvious option would be a solid conditioner bar, which many shampoo bar companies sell alongside their shampoo. Like a syndet shampoo bar, this is essentially a like-for-like replacement. Instead of squirting conditioner into your hand and rubbing it on your length, you rub the bar on your length and work it through, then rinse out like you would with ordinary conditioner.

For a lot of people, this is plenty. Simply replace your liquid shampoo and conditioner with solid bars, and continue your shower routine as usual. 

For others, however, rinse-out conditioner is only the start of the haircare story. If, like me, you have fine, straight, low porosity hair, you have to be careful with conditioner as it’s very easy to overdo it and be left with lank, greasy hair. I’m planning on trying a solid conditioner bar soon, but I would be lying if I said I’m not a little concerned it’ll just be too heavy. At the other end of the spectrum, if your hair is curly or damaged, you may need more than just a solid conditioner bar.

I feel like at this point I should add a disclaimer that I have very easy hair when it comes to moisturising. Because of my hair texture and porosity level, I tend to have problems with over-moisturising rather than under-moisturising. For most of my life I’ve not used conditioner at all, and I’ve grown soft, shiny hair past my hips (I do use conditioner and other moisturising agents now, as Canadian winters are much drier than in Scotland). So although I’ve done a lot of research into hair (yes, I’m a nerd), most of my haircare history has been more about avoiding weighing my hair down than keeping it moisturised.

There’s some science in this post that you may or may not be interested in; if you don’t care about it then you can skip to the ‘Alternatives to conditioner’ section for suggestions.

What is the point of conditioner?

To figure out how to switch to a plastic-free haircare routine, we need to back up and consider why we use conditioner and other products designed to moisturise hair. Whether you’re an old hand at smearing shea butter and coconut oil on your hair, or your typical routine consists of a line of Pantene products, the end goal is moisturised, hydrated hair.

But what does that mean? 

On a scientific level, it means there is adequate water in the hair shaft. That’s what moisture is. Not oil, not vinegar, not conditioner. Water. Moisturised hair is hair that retains water and doesn’t dry out.

That’s what hydrated hair is. But the second part of this is what we mean when we talk about moisturised hair. We’re not looking at the individual hair strands and wanting them to all contain enough water. No, we want soft, shiny hair, hair that has some slip to it and doesn’t break when we comb it. With curly hair, we want well-defined curls that clump together.

Conventional shampoo tends to dry out the hair, so then we need conditioner to restore some of that moisture. This post from Science-y Hair Blog does a really good job of explaining how conditioner works. Essentially, the role of conditioner is to trap moisture in the hair shaft. It also makes the hairs less likely to catch on each other and glide more smoothly against one another. In other words, conditioner gives the hair slip.

Alternatives to conditioner

Now that we’ve established that conditioner is not, in and of itself, moisturising, we can look at other ways to achieve the same effect: namely, trapping moisture in the hair. 

Shampoo comes first

If you’re switching to a gentler shampoo, you may find that you don’t need conditioner the way you used to. It might even make your hair lanky and greasy, as your hair is no longer being stripped of oils in the shower. 

Even without switching your shampoo, it’s important to address your shampoo technique to avoid dehydrating your hair as much as possible. Do you pile all your hair up on your scalp when you wash it, massaging the shampoo in from root to tip? 

If so, stop doing that. You only need to apply shampoo to the length of your hair if it’s actually dirty. It doesn’t get greasy like the roots do, so unless you’ve gotten mud or paint in your hair, focus on the scalp, and the suds rinsing down the length will be enough to remove any surface dirt and lint from your hair.

Acid rinses

I touched on this in my post about shampoo bars, but if you’re using a soap-based shampoo bar then you may see something like ‘finish with a diluted vinegar rinse as your conditioner’. This is because vinegar (or any weak acid) fulfills many of the same functions as conditioner: it closes the cuticle, helping to trap moisture and giving hair slip. 

If you have soft water and are using a pH-balanced shampoo, there’s likely no reason for an acid rinse as the cuticle hasn’t been opened much anyway. A vinegar rinse doesn’t bind to the damaged parts of the hair shaft the way conditioner does, so it doesn’t provide much benefit unless you’re using a soap-based (ie alkaline) shampoo, which lifts the cuticle.


Humectants are substances that draw water to them. That means that left on your hair, they draw water from the air and to your hair. This does depend on your climate to an extent, as in very dry weather humectants can actually draw water from your hair and into the air. In humid air, on the other hand, humectants will trap moisture in your hair.

Examples of humectants include things like honey, aloe vera gel, and glycerin. Glycerin is found in all soap-based shampoo bars, as it’s a byproduct of the soap-making process. Something like aloe vera gel can be applied straight to hair (either alone or mixed with an oil like coconut oil) as a leave-in conditioner, or added to a mister bottle to help keep the moisture in.


There’s a lot of misinformation about the role that oils play in haircare. Used for centuries in traditional haircare, they’ve had a bit of a renaissance in recent years with products like Moroccan oil, and people talk about what oils are the most moisturising.

No oil is moisturising. Oil is not water – in fact, it’s basically the opposite of water, as oil won’t mix with water. This makes oil great for sealing in moisture, so while oils are not moisturising, they can be used as part of an overall hair moisturising routine.

There are a few ways to use oil on hair. The first is as a leave-in, where you rub a couple of drops of oil (or a fingernail scraping for a solid oil like coconut oil) between your hands and apply it to damp hair from the ears down. The oil will help seal the moisture in the hair shaft.

Oil can also be used on dry hair to provide slip and shine. This is not moisturising in the way it is when you use it on damp hair, but it can provide some of the same properties. This is how I like to oil my hair, as when I do it on damp hair my hair can be left lank and feeling coated. Again, you just rub a couple of drops of oil between your hands and apply it to dry hair from the ears down. I like to comb my fingers through my hair and sort of smoosh the strands together between my palms to get everything coated.

Oil can also be used as a pre-wash treatment to protect the hair from the drying effects of shampoo. Again, from the ears down you want to finger comb oil through dry hair, and leave it on for several hours before you shower (the night before a morning shower is perfect). In this case, you want to use enough that you can tell there’s oil in your hair. You don’t need to overdo it, but there should be more than just a slight shine. What you’re aiming for is a level where you shampoo as normal and after washing your hair is soft and shiny and not greasy at all; you don’t want to use so much you have to use extra shampoo to remove it, as that defeats the purpose.

What oil or oils work best is very individual. Coconut oil, sunflower oil, argan oil, sweet almond oil, and jojoba oil all come to mind as popular. In the interests of sustainability, I would recommend starting with any of those that you have in your kitchen or bathroom cabinet already. Olive oil can also work well as a pre-wash treatment, particularly on coarse hair, though you may find it too viscous for hair you’re not going to wash shortly afterwards. 

Mister bottle

A mister bottle is just a spray bottle filled with water (preferably filtered or distilled for longevity) and other optional ingredients. You want one that produces a fine mist rather than a squirty one, as you want to get good coverage across your hair, and you typically just want your hair damp, not wet.

I typically just use water and an essential oil blend for scent, but you can also add humectants and oils for the properties I’ve described above. A simple blend of water, aloe vera gel, and a few drops of sunflower oil, for instance, would add water to the hair, provide a humectant to draw moisture from the air into the hair shaft, and seal all that lovely moisture in with the oil.

A final note

I think haircare is one of those areas that can often be overlooked when it comes to sustainable living. This is improving with more widespread awareness of solid shampoo and conditioner bars, but for many of us the reality is still that we have plastic bottles on the shelves of the shower and more plastic bottles in the bathroom cabinet. 

My hope is that this post will give you some ideas for whatever it is you’re struggling to replace. Shampoo and conditioner bars are a fantastic start, but for many of us they really are just the start, especially for those of us who like to experiment with haircare. As a bonus, all of these suggestions are hair-friendly, so they’re great if you’re trying to reduce damage and grow healthy hair. 

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