Sayuri Science · Ingredient Guide
Zechstein magnesium is natural magnesium chloride — the mineral bischofite — from the remains of the Zechstein Sea, which evaporated around 250 million years ago and now lies deep beneath Veendam in the north of the Netherlands. In skincare, magnesium helps the skin hold water, supports faster recovery of the skin barrier and calms redness. It is the heart of Sayuri BioMineral™, the mineral complex in our Glowing Skin and Matrix formulas.
By Katerina Trofimova, biochemist and founder of Sayuri · Last updated: November 2026
What is Zechstein magnesium (bischofite)?
About 250 million years ago a shallow inland sea, the Zechstein Sea, covered much of northern Europe. As it repeatedly evaporated, it left thick salt layers. Magnesium chloride is the last salt to crystallise from seawater, and under Veendam it formed a rare, thick layer of bischofite — magnesium chloride hexahydrate (MgCl₂·6H₂O) — more than a kilometre below the surface.
It is extracted by solution mining: water is pumped down, dissolves the mineral and returns as a concentrated brine, which the Dutch producer Nedmag processes in Veendam. For the Zechstein Inside® quality line, each production batch receives its own certificate of origin with trace-element analyses measured down to parts per billion (Zechstein Inside). Because the deposit has been sealed underground since long before modern pollution, the raw material needs no chemical purification.
For me this ingredient is personal. My first degree is in mining engineering — the science of what lies beneath the surface. Using a mineral from the ground beneath the Netherlands, in the country where Sayuri was born, connects both of my disciplines.
What does magnesium do for the skin?
- It helps the barrier recover. In a study on mouse skin, a 10 mM magnesium chloride solution accelerated skin barrier repair after the barrier had been damaged by tape-stripping; a balanced mix with calcium worked best (Denda et al., 1999).
- It hydrates and calms. In a controlled human study, bathing one forearm in a magnesium-rich salt solution improved barrier function and skin hydration and reduced roughness and redness compared with tap water. The authors attribute this to the high magnesium content: magnesium salts bind water and influence how skin cells grow and mature (Proksch et al., 2005).
- It supports skin repair. In cell studies, magnesium chloride sped up the migration of keratinocytes — the cells that close a wound — through the MEK/ERK pathway (Yoshino et al., 2024). This is early, laboratory-only evidence.
What magnesium does for the skin
Summary by Katerina Trofimova. “Moderate” = supported by controlled studies; “early” = laboratory data only.
What Zechstein magnesium does not do
Many “magnesium oil” brands claim that magnesium sprayed on the skin raises magnesium levels throughout the body. A scientific review found no rigorous evidence for this and concluded that transdermal magnesium for the whole body is not scientifically supported (Gröber et al., 2017).
Sayuri makes no such claim. We use magnesium for what the evidence does support: the condition of the skin itself — its barrier, hydration and calm. If you are concerned about your magnesium levels, speak to your doctor.
Zechstein magnesium and the Longevity Axis™
In the Longevity Axis™, magnesium is the core of the mineral axis: the skin’s ability to hold water, keep its barrier intact and renew its surface. Because a healthy barrier also calms the skin, Sayuri BioMineral™ supports the other two axes as well — which is why it appears across our lines.
Which Sayuri products contain Zechstein magnesium?
- Glow Reset Cleansing Mask — 9% Sayuri BioMineral™ with salicylic acid, bentonite, kaolin and zinc oxide.
- Glow Reset Tonic — 2% Sayuri BioMineral™ with enzymatic renewal and NMF.
- Glow Perfection Drops™ — multi-acid serum with Zechstein BioMineral™ and Schizophyllan.
- Matrix Sculpture Drops — firming serum for mature skin, with Zechstein BioMineral™.
Frequently asked questions
What is the difference between Zechstein and Dead Sea magnesium?
Both are natural magnesium chloride. Dead Sea salt is obtained by evaporating today’s lake water and contains a mix of salts. Zechstein bischofite comes from an ancient, sealed deposit and is mined as a concentrated magnesium chloride brine with only trace amounts of other minerals.
Is magnesium chloride the same as Epsom salt?
No. Epsom salt is magnesium sulphate. Sayuri uses magnesium chloride, the form studied in the barrier-recovery research above.
Can magnesium sting on the skin?
Concentrated magnesium brines (“magnesium oil”) can tingle, especially on dry or damaged skin. In Sayuri formulas the mineral is used at cosmetic concentrations within a balanced formula, so it is well tolerated. Avoid applying any product to open wounds.
Is Zechstein magnesium natural?
Yes. It is a natural mineral, mined without chemical purification and with batch-by-batch analysis of its origin and purity.
Sources
- Denda M, Katagiri C, Hirao T, Maruyama N, Takahashi M. Some magnesium salts and a mixture of magnesium and calcium salts accelerate skin barrier recovery. Arch Dermatol Res. 1999;291:560–563. PubMed 10552215
- Proksch E, Nissen HP, Bremgartner M, Urquhart C. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin. Int J Dermatol. 2005;44(2):151–157. PubMed 15689218
- Yoshino Y, Teruya T, Miyamoto C, Hirose M, Endo S, Ikari A. Unraveling the mechanisms involved in the beneficial effects of magnesium treatment on skin wound healing. Int J Mol Sci. 2024;25(9):4994. MDPI
- Gröber U, Werner T, Vormann J, Kisters K. Myth or reality — transdermal magnesium? Nutrients. 2017;9(8):813. PMC5579607
- Zechstein Inside — source presentation: geology, solution mining and batch certificates of origin. Presentation
Sayuri products are cosmetics intended to support the appearance and condition of the skin. They are not medicines and do not treat or prevent disease.
