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The best shampoo bar of 2024: There's one that works, and it's amazing

Making the switch to bar shampoo can help save the planet — and your hair too.

 bar shampoo on blue background
The best bar shampoo we tried was from Superzero. (Amazon)

Last fall, an environmentally-conscious pal sent me a shampoo bar from a brand called Superzero: "OMG you HAVE to try it — it's the best shampoo bar," she wrote in an accompanying text. "My hair is so soft and it's SO MUCH better for the planet." The shampoo she'd sent was for fine hair, which I have (you can find shampoo bars for most any hair type: curly hair, gray hair, thinning hair, for dandruff, etc). It looked like a hard bar of soap, like the kind of soap at my grandmother's house, the kind I hadn't seen — or used — in years. I texted my friend back ("Thank you so much, can't wait!"), then proceeded to leave the hard bar shampoo in the box for ... a while. I must admit I was skeptical about using my gifted bar shampoo. It sat there for months.

Quick overview

But a new year changes a person, or at least we often want it to. According to an estimate by Johnson & Johnson (reported in the Washington Post last year), in the U.S. alone, 552 million empty shampoo bottles are thrown away each year — enough to fill more than 1,100 football fields (and that's just shampoo, not conditioner or any other hair products). When packaged in eco-friendly packaging, shampoo bars are close to zero waste. I wanted to be a more responsible consumer. I decided to try the bar shampoo.

How do shampoo bars work?

Bar shampoo works a lot like regular shampoo. All you do is wet your hair and massage the bar into the crown of your head (a circular motion worked best for me). It lathers quickly and you suds the lather around. Then you rise it out. The first time I tried Superzero's bar shampoo, I was surprised by how well it lathered, how actually not weird at all the experience felt. I followed up with a regular conditioner (though I've since switched to bar conditioner too). I blew my hair dry. It looked shiny. It felt silky. There was truly zero frizz (even on a rainy day in L.A.). I didn't understand how a bar shampoo could work so well. I decided to find out.

I contacted Dr. Conny Wittke, Superzero's founder, who gave me the lowdown.

Are shampoo bars better than regular shampoo?

As it turns out, the liquid shampoos most of us use are extremely watered down. In fact, 80 to 90% of most liquid shampoo is just water. According to Dr. Wittke, Superzero's hair-fortifying ingredients are five times more concentrated than liquid shampoo. The more concentrated a high-quality ingredient, the stronger it is and (often) the better it works.

Bar shampoo is also more cost effective. "While one bar looks small, it is very mighty," Dr. Wittke told me, "one bar represents two 8.4oz bottles of liquid shampoo."

Shampoo bars are travel friendly, too, not only space efficient, but 100% TSA approved (and — bonus — will never explode all over your bag).

And of course, the zero-waste/eco-friendly reason: solid shampoo avoids both plastic waste and microplastic waste, significantly reducing shampoo’s (and your own) carbon footprint. Plus, says Dr. Wittke: "It reduces your exposure to chemicals in plastics that have known negative health effects."

What makes a good shampoo bar?

Once I tried Superzero's shampoo bar, I wanted to try more like it. What else was I missing? I wanted to find every best shampoo bar! However, the problem, I quickly found, is not all bar shampoos are created equal. In fact, most every brand I tried outside of Superzero was ... not great.

Some were too crumbly, some too hippie-co-op greasy. Some stripped my hair, some felt just ... strange, like I was shampooing with dish soap. And, as it turns out, I kind of was. There's a complicated science to this, but mainly: to be effective and not harm your hair, bar shampoos must be made with ingredients specifically designed for follicles in mind. That's because bar soap (like the kind you find in soap dishes) has a super high pH level which can damage the hair shaft and make your hair feel rough. Over time, it also builds a kind of soap scum on your strands, leaving them dull and flat.

Unfortunately, many shampoo bars on the market are made with the same ingredients used in regular soap (things like sodium stearate, sodium olivate or sodium cocoate). When I really started investigating, I found few bar shampoos that didn't contain primarily soap ingredients. And the ones that didn't? They were mostly unpleasant to use — they fell apart too easily or just didn't come close to recreating the wash and effect of a high-quality liquid.

Best shampoo bar of 2024

Unlike the other brands I tried, the Superzero shampoo bars were uniformly stellar. I tried four different types — for fine hair, for thinning hair, for blonde hair and for damaged hair. I sent a curly-haired friend a shampoo bar for curly hair and she said she liked that one too (though she liked using the conditioner better as a shampoo). Note: All Superzero shampoos are vegan, sulfate- silicone- and paraben-free. The pros and cons for all are mainly the same, mostly I like them but I don't like that 1. they're almost $30 and 2. they're harder to store than liquid formulas, even with the handy complimentary storage bag.

I have to admit: I was skeptical before trying Superzero's bar formations, but the all-natural shampoo left my hair in better shape than it had been in months — silky, full, shiny, manageable. I only wish it were cheaper and, as with any bar soap, a little less unwieldy to store. 

$28 at Amazon

Made with ultra-moisturizing shea butter, this bond-building shampoo is gentle, sulfate-free, silicone free and fragrance free — an excellent option for damaged hair that needs a little TLC.

$22 at Sephora

Listen, after using this particular blue-hued shampoo bar, my blonde hair looked brighter and more golden — in a good way.  

$28 at Amazon

Thinning hair requires products that both nourish and condition strands without weighing them down. Made with caffeine (to stimulate skin on your scalp), rosemary oil and vitamin D-rich Amla extract, this thinning hair shampoo bar achieved all three.  

$28 at Amazon

Using a variation of the "curly girl method", my friend used this bar conditioner as a shampoo — she lathered it up and only half rinsed it out. "My curls stayed in tact," she told me after. "And I had very little frizz, even by the end of the day."

$28 at Amazon