The science behind Dead Sea mud

The Dead Sea sits about 430 metres below sea level, at the lowest exposed point on the planet. It is roughly ten times saltier than the ocean, salty enough that fish carried in by the Jordan river do not survive it. Nothing much lives there. People have been travelling to sit in it for at least two thousand years.

The black mud from its shores has been used on skin for about as long. Here is what is actually in it, and what we think a bar of soap can and cannot do with it.

It is the mineral mix, not the saltiness

Ordinary seawater is dominated by sodium chloride — table salt. The Dead Sea is unusual because its salt is mostly something else: magnesium chloride, along with substantial calcium, potassium and bromide. The mud that settles on its shores carries that profile with it, bound up in fine silt clay.

Magnesium is the one researchers have paid most attention to. It is involved in skin barrier function and in how the outer layer holds onto water, and it is the reason Dead Sea minerals get studied at all rather than being filed under folklore.

What the research shows — and what it does not

There is a real body of work here, but it is worth being precise about what it covers. Small clinical studies on bathing in magnesium-rich Dead Sea salt solution have reported improvements in skin hydration and barrier function, and reduced roughness, in people with dry skin. There is a longer tradition of research into Dead Sea balneotherapy — extended, supervised soaking, usually combined with sunlight — for conditions like psoriasis.

Notice what all of that has in common: people sitting in mineral water for twenty minutes at a time, often daily, for weeks. That is not a bar of soap. A soap bar is in contact with your skin for perhaps a minute, and then you deliberately rinse it off.

So we will not tell you that washing with our Sea Clay bar delivers the clinical outcomes of a fortnight at the Dead Sea. It does not, and any brand claiming otherwise is hoping you will not read the studies.

What the mud genuinely does in a bar

Quite a lot, just not medically.

• It absorbs. Fine mineral clays bind excess sebum and lift it away as you rinse. This is why clay bars suit oily and combination skin and can feel too thorough on very dry skin.
• It gives slip. Clay changes how a bar moves over wet skin — a silkier glide, and a denser, creamier lather than the same recipe without it.
• It colours the bar. Every shade in our Sea Clay bar comes from the mud, the French green clay and a little spirulina. There is no dye in it, which is also why no two batches are precisely the same grey-green.
• It cleans without stripping. Paired with a hydrating base of olive and rice bran oils, you get the absorbency of clay without the tight, scrubbed-out feeling that a harsher cleanser leaves behind.

Who it suits

Sea Clay pairs Dead Sea mud and French green clay with eucalyptus, peppermint and rosemary. If your skin runs oily or combination, or you want a bar that wakes you up properly in the morning, it is the one. If your skin is dry or easily irritated, Tangerine Bloom is the gentler choice — same care, less absorbency.

And if you want the version of this with charcoal rather than clay, Mooncoal does a similar job with activated charcoal and tea tree.

Not sure which suits your skin? Tell us about it and we will point you at the right bar, including when the right answer is none of ours.