Peat

Peat is not soil, not mud, and not compost. It’s a unique organic sediment formed over thousands of years as plant material — primarily sphagnum moss — partially decomposes in waterlogged, acidic, oxygen-starved bogs. The process is extraordinarily slow: about 1 mm per year. A metre of peat represents a millennium of chemistry.

What makes peat remarkable for skin and health applications is what that slow decomposition produces: a concentrated cocktail of bioactive compounds — humic acids, fulvic acids, phenolics, tannins, minerals, and lipids — found nowhere else in nature in this combination.

What’s inside

Peat is a complex mixture, and its exact composition varies by type, depth, geography, and how far decomposition has progressed (measured on the von Post scale from H1 to H10). But the major components are consistent:

• Humic acids — 10–40% of dry mass. The primary bioactive fraction: anti-inflammatory, antimicrobial, antioxidant. Estonian peat reaches up to 39.3% in some deposits (Orrù 2011); Finnish averages 24.8–26.8% (Korhonen 2008), corroborated by a single-site Finnish mire report at 28.5% (Korhonen 2005) and a commercial manufacturer spec of 25–30% (innovation-company-2020).
• Fulvic acids — 5–20% of dry mass. Smaller, more bioavailable, shown to penetrate human skin in vitro (Beer 2003). Finnish mire data converges around 9–10% (Korhonen 2008, Korhonen 2005), with one commercial spec running slightly higher at 8–12% (innovation-company-2020).
• Hymatomelanic acids — up to 19.3% in some Estonian peatlands. An ethanol-soluble fraction strongly correlated with biologically active lipids.
• Humin — 20–50% of dry mass. Insoluble. Structural role — contributes to peat’s exceptional thermal retention and water-holding capacity.
• Phenolic compounds and tannins — antioxidants and astringents. Give peat its preservative and skin-toning properties.
• Minerals — iron, zinc, magnesium, sulfur, calcium, manganese, and trace elements. All 34 elements tested in Estonian peat were below hazardous levels (Orrù 2010); a single-site Finnish mire report found 23 trace elements at consistently low, therapeutically relevant levels (Korhonen 2005).
• Polysaccharides — moisture-binding compounds, including sphagnan, a unique antimicrobial polysaccharide from sphagnum moss.
• Waxes and lipids — emollient compounds that soften skin and slow moisture loss.

Two types, different strengths

Sphagnum peat (from raised bogs) — rain-fed, highly acidic (pH 3.5–4.5), lower mineral content, higher fulvic acid ratio, lighter colour. This is the type used in Estonian and Nordic cosmetic products. Its purity comes from being fed only by rainwater, not groundwater.

Lowland peat (from fens) — groundwater-fed, less acidic, richer in minerals and humic acids, darker. The traditional peat of Central European balneotherapy — Czech, German, Hungarian, and Austrian spa medicine has used this type for over two centuries.

Both types are therapeutically active, but through different balances of compounds. The quality threshold for either type is a humification degree of H6 or higher and humic acid content above 20% of dry weight (Korhonen 2008).

Physical properties that matter

Heat retention. Peat holds temperature far longer than water or clay. A peat mixture loses less than 1°C over 20 minutes, while water drops 3.5°C in the same period (Korhonen 2008). This is why peat baths deliver sustained thermal therapy that hot water baths cannot match.

Water holding. Peat can hold up to 20 times its dry weight in water — comparable to a sponge. This physical property underpins its use in body wraps and mud packs, where the peat matrix maintains contact with skin while delivering its chemistry.

pH compatibility. Peat’s natural acidity (pH 3.5–5.5) aligns with the skin’s acid mantle (pH 4.5–5.5), supporting the barrier function rather than disrupting it — a significant advantage over alkaline treatments.

Not one compound — a system

The most important thing to understand about peat is that it works as a system, not as a single active ingredient. The anti-inflammatory action of humic acids combines with the antioxidant protection of phenolics, the mineral delivery of fulvic acids, the moisturising effect of polysaccharides and lipids, the sustained heat delivery of the physical matrix, and a preliminary microcirculation stimulation effect observed even without external heat. Isolating any one compound loses the synergy that makes whole-peat applications effective.

This is why peat can address psoriasis, eczema, joint inflammation, dry skin, and skin aging — not because it contains one miracle ingredient, but because it delivers multiple mechanisms simultaneously through a single natural material.