Development of a microalgal peloid for thermotherapeutic uses

Open-access study published in the International Journal of Biometeorology (2025) developing a novel peloid formulation — combining mineral water, clay-silt substrate, microalgae, and rosmarinic acid — and characterising its thermophysical properties for therapeutic use. The peloid developed here is not peat, but the study provides thermal property benchmarks that contextualise peat within the broader peloid framework.

What Was Developed and Measured

The novel peloid combines four components: a mineral water base (providing the ionic environment), a clay-silt mineral substrate (providing structure and thermal mass), microalgae (a biological anti-inflammatory additive), and rosmarinic acid (a polyphenolic anti-inflammatory). Three thermophysical parameters were characterised: specific heat capacity (energy stored per gram per degree), thermal conductivity (rate of heat transfer), and density.

These parameters determine how a peloid behaves as a thermotherapeutic agent — how much heat it stores and how slowly it releases that heat to tissue. The microalgal peloid was optimised for the same thermal retention criteria that make peat therapeutically useful: high specific heat, low thermal conductivity.

Relevance to Peat

Peat, fango, clay mud, and now microalgal peloids are all competing in the thermal peloid space. Mourelle 2025 provides comparative thermal property data from modern formulation research. Nordic sphagnum peat’s thermal properties (documented in Korhonen 2008) compare favourably with clay-based peloids; this study provides a contemporary benchmark for that comparison.

The Peloid Classification Note

The paper reviews peloid classification — inorganic (mineral muds), organic (peat, sapropel), and mixed — as context for the new formulation. This confirms the classification framework established in Gomes 2013 is still the operative standard in the field.