Iron

Iron is the most abundant mineral in peat. It gives peat much of its dark brown to black colour, and it plays an essential role in oxygen transport and tissue repair. But iron in peat behaves very differently from iron in a supplement pill — and that difference matters.

How peat delivers iron

Free iron ions are reactive and potentially harmful — they catalyse oxidative damage to cells and form insoluble rust-like compounds that the body can’t use. In peat, iron exists as Fe²⁺ and Fe³⁺ ions chelated by humic acid and fulvic acid functional groups. This chelation does two things at once: it keeps iron bioavailable (the body can absorb it) while preventing it from becoming a pro-oxidant (the humic acids control its reactivity).

During a peat bath, these iron-humic complexes come into contact with the skin. Fulvic acids — which are small enough to penetrate the skin barrier — can carry chelated iron with them, providing mineral delivery directly to skin tissue (Pant 2014).

What iron does for the skin

Iron is a cofactor for collagen synthesis — the structural protein that holds skin together and is essential for wound healing. It’s also central to oxygen transport: haemoglobin (which carries oxygen in blood) depends on iron, and adequate tissue oxygenation is critical for skin repair.

Iron content varies enormously between peat sources. Estonian peat deposits range from 159 mg/kg (Kõverdama upper layers) to 17,100 mg/kg (Kõverdama lower layers) — a 100-fold variation that underlines why peat source matters for therapeutic applications (Orru 2005).

A built-in safety mechanism

The chelation by humic acids isn’t just a delivery system — it’s a safety mechanism. Free iron generates hydroxyl radicals via the Fenton reaction, damaging cells. By keeping iron bound in stable complexes, peat delivers the mineral benefits without the oxidative risk. This is one of the subtler ways peat’s chemistry is self-regulating.