Short answer: for most people, a well-formulated bar soap without SLS or synthetic detergents is gentler on your skin than a standard bottled body wash, and the two cost roughly the same per wash at the mass-market end (around 5p either way). Where bar soap genuinely wins is what it leaves out of your bathroom altogether: no plastic bottle, no sulfates, no long list of synthetic preservatives.

There's a moment in most people's bathroom cabinet when the shower gel runs out mid-lather and you're left standing there, freezing, rinsing off with just water while you decide whether it's worth the walk to the cupboard. It happens more than anyone admits. And it's usually the moment someone Googles whether they should just go back to a bar of soap like their nan used to keep by the sink.

We get asked this a lot, not because we're trying to convert everyone off body wash on principle, but because we make bar soap for a living and we'd rather tell you the truth than sell you a story. So we went and actually priced this out, properly, against real products on real UK shelves, rather than repeating the usual "bar soap is cheaper and better, obviously" line you'll find on most soap company blogs (including, historically, some of our own).

The honest answer turned out to be more interesting than either side of the argument usually admits.

It depends far more on the formula than on whether the product is solid or liquid, and that's the part most "bar vs bottle" articles skip over. Traditional cold-process soap is made through saponification, which leaves it naturally alkaline, usually somewhere around pH 9 to 10, against your skin's own surface which sits closer to pH 4.5 to 5.5. That gap is real, and it's why old-fashioned bar soap can leave skin feeling tight after a hot shower.

But most bar soap sold today, MGR's included, isn't traditional lye soap. It's a formulated bar built with plant oils and butters and deliberately left out of SLS and synthetic sulfates, which is a different thing entirely from your gran's carbolic soap. Meanwhile plenty of bottled body wash leans on sodium laureth sulfate (SLES) or similar sulfates to get that big satisfying lather, and sulfates are one of the better-documented irritants in personal care. A widely cited in-vivo study on sodium lauryl sulfate found it visibly disrupts the skin barrier, altering the proteins your skin relies on to repair itself, at concentrations far lower than what shows up in some everyday cleansers.

So the format isn't really the variable. The ingredient list is. A syndet (synthetic detergent) bar or an SLS-free body wash can both sit close to skin-neutral pH; a harsh sulfate-heavy bottle and an old-school alkaline bar can both leave you tight and flaky. If your skin reacts to whatever you're using now, the fix is reading the ingredient list, not switching formats on faith.

Take a genuinely popular one as an example rather than a strawman: Dove's Sensitive Skin Body Wash, sold in every UK supermarket. Its ingredient list includes sodium laureth sulfate as a primary cleanser, a generic "fragrance" that (per independent ingredient audits) typically stands in for anywhere from 30 to 50 undisclosed chemical compounds, and methylisothiazolinone, a preservative that dermatology bodies have flagged as one of the more common causes of allergic contact dermatitis in leave-on and rinse-off products alike. None of that makes it a bad product exactly, it's a mass-market cleanser doing what it's formulated to do cheaply and at scale, but it's worth knowing what "sensitive skin" actually means on the label versus what's in the bottle.

This is the same reasoning that shaped our own toothpaste tablets, if you're wondering why a soap company keeps bringing up dental care: we left SLS and synthetic fragrance out of our nano-hydroxyapatite toothpaste tablets for the same reason we leave it out of the soap bars, because "foams a lot" and "gentle on skin" are frequently two different formulation goals pulling in opposite directions.

It's part of why our body wash bars are built around plant oils and vitamins A, C and E rather than a sulfate-and-fragrance base, in a solid 80g bar with no bottle to throw away once it's used up.

This is where most comparisons get lazy, so we ran the actual maths using real UK retail prices and a couple of well-sourced usage estimates: roughly 20 to 30 showers from a standard 100g-ish bar of soap, and 5 to 10ml of body wash per shower for a full-body cleanse. Scaled proportionally to each product's real size, here's what a single wash works out to.

The honest headline here: mass-market bar soap and mass-market body wash cost almost exactly the same per wash, roughly 5p either way. Format isn't what makes something cheap or expensive, scale of manufacturing is. Naturally formulated products, whether bar or bottle, both cost more per wash than a supermarket own-brand, and that's true of Faith in Nature's bottle just as much as our own bars.

So we're not going to pretend our bars beat Dove on price, because they don't, not per wash. What they do differently is leave synthetic sulfates and generic "fragrance" out of the formula entirely, and remove the plastic bottle from the equation altogether, which is where the real case for switching actually sits.

Formulated without SLS, synthetic fragrance, or a plastic bottle to throw away.

This is the objection we hear most often, and it's largely a myth that's outlived the science behind it. A frequently cited study published in Epidemiology and Infection tested bar soap deliberately contaminated with bacteria and found it was very unlikely to transfer that bacteria back onto a person's hands during normal washing. Weill Cornell Medicine's dermatology department addresses the same worry directly, noting that while germs are present on nearly every surface you touch, contact with them "won't automatically make you sick, otherwise we'd all be sick all the time." Rinsing a bar under running water between uses, and keeping it somewhere it can actually dry out rather than sitting in a pool of water, deals with the rest.

Where hygiene genuinely matters more is shared bathrooms with someone who's actively unwell, in which case liquid soap in a pump dispenser removes even the small residual risk. For everyday solo or family use, it's a non-issue.

This is the part the cost-per-wash table doesn't capture. UK households produce roughly 1.5 million tonnes of single-use plastic waste a year, of which only around 9% gets recycled, and bathroom bottles are a meaningful share of that. The average person in the UK gets through about 61kg of shower gel annually, almost all of it packaged in plastic that either gets binned, gets "wish-cycled" into a recycling stream that can't actually process it, or ends up incinerated.

A soap bar sidesteps that packaging question entirely. There's no bottle, no pump mechanism, no cap, nothing to sort into the right bin or forget to rinse out. It's the one part of this comparison where format, not formulation, is doing the work, and it's the reason we'd still make the case for bars even in the sections above where they don't come out ahead on price.

If you're going to make the switch, it's worth doing it properly rather than swapping one irritant for another. A few things worth checking on the ingredient list before you buy: no sodium lauryl sulfate or sodium laureth sulfate, since both can strip natural oils regardless of format; a short, named ingredient list rather than a generic "fragrance" entry; and plant oils or butters doing the moisturising work rather than glycerin alone, which cleans but doesn't replace lost lipids.

Our own bars lean on vitamins A, C and E to help smooth and calm skin texture while the plant oil base does the actual cleansing, and every one ships with a free travel tin and a sisal face exfoliator so there's somewhere to keep the bar dry between showers, which, per the hygiene point above, is genuinely the thing that matters most.

A note from Jonny: questions like this one are genuinely my favourite part of running MGR, because the honest answer is rarely as clean as "our product wins." Bar soap doesn't beat Dove on price, and I'd rather say that plainly than dress up a comparison to make it look better than it is. If you want the full experience of natural hair and body wash without thr harsh chemicals, we have the perfect starter kit for you. 

If you've made the switch either way, bar or bottle, natural or not, we'd genuinely like to hear how your skin got on with it, drop a comment below or find us on Instagram. And if you're still somewhere in the middle of your own personal care detox, working out which swaps are actually worth making and which ones are just marketing, that's exactly what the rest of this blog is here for.