The Bar Soap Comeback: Why Dermatologists Changed Their Minds

Something unusual is happening in skin care coverage this year: dermatologists are publicly rehabilitating bar soap. After two decades of "bars strip your skin — use a gentle wash," the expert consensus has shifted to bars being a perfectly good choice, with the old tight, dry feeling blamed on unbalanced formulas that many brands have since corrected.

As a pharmacist who makes soap, I welcome the correction. But the mainstream version of this story leaves out the most interesting parts — and gets one piece of chemistry conveniently blurry. So here is the fuller, more honest account of why bar soap got its bad name, what actually changed, and what the headlines will not tell you.

First, the Real Chemistry: What "pH" Has to Do With Your Skin

Your skin's surface is mildly acidic — around pH 4.5 to 5.5. That acidity is not incidental. It is a functioning defence layer, often called the acid mantle, that keeps the skin's barrier proteins working and makes life difficult for unwanted bacteria and fungi.

Wash with something strongly alkaline and you knock that acidity out temporarily. Healthy skin recovers in a few hours. But wash repeatedly with a harsh, high-pH cleanser — especially skin that is already dry, sensitive, or eczema-prone — and the recovery falls behind the damage. The result is the tightness people learned to associate with bars.

Now the Part the Headlines Blur

Here is the fact most coverage tiptoes around: true soap — the real thing, made by reacting oils with lye — is naturally alkaline, typically around pH 9 to 10. That is not a defect. It is the chemistry of what soap is. You cannot take a genuine bar of soap down to skin pH 5.5; below a certain point the soap molecules themselves break apart and it stops being soap at all.

So when a famous "gentle" commercial bar advertises being pH balanced to skin, it can do that because it is not soap. It is a syndet bar — a pressed block of synthetic detergents that can be formulated to any pH. Nothing wrong with that as a product category. But it means the market quietly split into two different things wearing the same shape, and shoppers were never told.

So Why Did Old Commercial Bars Feel So Harsh?

If handmade soap and old-fashioned commercial soap are both alkaline, why did the commercial bars earn the terrible reputation? Two reasons, and pH is only the beginning of the story.

Reason one: the glycerin was removed. When oils turn into soap, the process naturally produces glycerin — the humectant that draws moisture to your skin. Large manufacturers separate that glycerin out and sell it as an ingredient for lotions and other products, because it is worth more on its own. The bar you bought was soap with its built-in moisturiser deliberately extracted. Handmade soap keeps every bit of its glycerin, because a small maker has no reason to take it out. This single difference explains more of the "handmade feels different" experience than any other factor.

Reason two: no cushion of oils. Well-made handmade soap is superfatted — formulated so a small percentage of the oils remain unconverted, left in the bar as free oils that buffer the cleansing action. Old commercial bars ran lean, converting everything, sometimes adding harsh synthetic surfactants on top. Alkalinity plus no glycerin plus no free oils: that combination, not the bar format, was the villain.

What "Fixed" Bars Actually Means

When today's coverage says brands adjusted their formulas, it describes several different corrections at once: syndet bars brought their pH down to skin range, some brands blended true soap with milder synthetic surfactants, and others — including small makers who never changed — rely on retained glycerin and superfatting to make an alkaline bar behave gently.

That last point matters, because it answers the obvious question: can a naturally alkaline handmade bar really be gentle? Yes — and the mechanism is no mystery. The brief, mild pH rise from washing is quickly restored by healthy skin, while the retained glycerin and free oils replace what washing removes. What damaged skin historically was not one wash at pH 9. It was daily washing with stripped, lean, additive-heavy bars, year after year.

Where Liquid Soap Fits

Liquid castile soap plays by slightly different rules, and this is where careful formulation shows. A liquid soap can be brought closer to skin-friendly territory with an acid — we use measured additions of citric acid in our liquid range — but there is a floor: take any true soap too far down and it breaks. A pharmacist's job is to find the honest position between "as gentle as the chemistry allows" and "still actually soap" — and to resist printing claims the chemistry cannot support.

That is also why you should raise an eyebrow at any true soap, bar or liquid, marketed as "pH 5.5." Either it is not soap, or the label is not telling the truth. There is no third option.

How to Choose, Now That You Know

The Comeback Was Really a Correction

Bar soap did not suddenly become good. Honest bar soap was always good — it was cost-cutting formulas that earned the format its reputation, and it is better formulation that has redeemed it. The dermatologists changed their minds because the products in front of them changed. Ours did not have to.

Every J.C. Epiphany bar is made the way this article describes good soap: full glycerin retained, superfatted, scented only with named essential oils or nothing at all, and formulated by someone who will tell you exactly what the chemistry can and cannot do.