By Cosmetic Peat Editorial Team Updated June 2026
Fulvic Acids
If humic acids are the heavyweight champion of peat, fulvic acids are the lightweight that punches above its weight. Smaller, lighter, and soluble in water at any pH, fulvic acids can go where humic acids can’t — including through your skin.
Fulvic acids are the low-molecular-weight fraction of humic substances. They’re yellow to light brown (compared to the dark brown-black of humic acids), make up 5–20% of peat’s dry mass, and are increasingly the compound that cosmetic science is most excited about.
What makes fulvic acids different
The key word is bioavailability. Humic acids are large molecules (10,000–100,000+ Da) that mostly stay on the skin surface. Fulvic acids are 10–100 times smaller (1,000–10,000 Da), with more reactive functional groups per unit mass. This gives them two critical advantages:
They penetrate skin. Beer (2003) showed that specific fulvic acid fractions permeate excised human full-thickness skin in laboratory conditions and exert pharmacological effects on the other side. This gives the “chemical effect” theory of peat therapy a physical basis — under lab conditions, bioactive compounds can cross the skin barrier — though it doesn’t by itself confirm how much penetration occurs during a real-world peat treatment.
They carry minerals with them. Fulvic acids are natural chelators — they bind mineral ions (zinc, iron, magnesium) and transport them across biological membranes (Pant 2014). In Estonian peatlands, fulvic acid concentration correlates strongly with trace metals: cadmium (r=0.91), thorium (r=0.86), zinc (r=0.76) (Orrù 2011). This mineral delivery function makes fulvic acids a natural vehicle for getting skin-relevant minerals where they’re needed.
What fulvic acids do
Calm inflammation through a specific pathway. Fulvic acids suppress the chemokines CCL17 and CCL22 — key drivers of eczema — by deactivating the p38 MAPK and JNK signalling pathways in skin cells. In a mouse model of atopic dermatitis, topical fulvic acid reduced ear swelling, redness, and blood levels of these chemokines in a dose-dependent manner (Wu 2023). A 2026 study confirmed that fulvic acid suppresses NF-κB (the master inflammatory switch) by neutralising its trigger while preserving the protective anti-inflammatory signal IL-10 (Szwed-Georgiou 2026).
Stop itching at the source. Fulvic acids from Canadian sphagnum peat inhibit the release of histamine from mast cells and basophils — the same cells that antihistamine drugs target (Yamada 2007). This anti-pruritic effect is particularly relevant for eczema and allergic skin reactions, where itch drives the scratch-inflammation cycle.
Accelerate wound repair. In a rat wound model, a 0.5% fulvic acid poultice produced fibroblast counts three times higher than control and angiogenesis 3.5 times higher (Samiee-Rad 2022). A cell migration assay confirmed the pro-regenerative effect (Szwed-Georgiou 2026). The mechanism involves Nrf2 pathway activation and IL-10 overexpression (Benderskiy 2022) — shifting the wound from stuck inflammation into active repair.
Scavenge free radicals. Fulvic acids are potent antioxidants, protecting skin cells from oxidative stress caused by UV exposure, pollution, and ageing (Winkler 2018).
In peat
Fulvic acids make up 5–20% of peat dry mass. The ratio relative to humic acids is higher in sphagnum (raised bog) peat than in lowland fen peat. Interestingly, fulvic acid concentration decreases with humification (Korhonen 2008) — meaning younger, less decomposed peat layers have proportionally more fulvic acid. Finnish peat averages 9.6% fulvic acid across both sphagnum and sedge types. Estonian values are lower: as low as 1.3% in some deposits, up to 3% at Kõverdama (Orrù 2011).
Where it matters
Fulvic acids are most relevant for:
- Eczema — the CCL17/CCL22 suppression and histamine inhibition are directly targeted at atopic dermatitis mechanisms
- Wound healing — fibroblast and angiogenesis stimulation
- Skin aging — antioxidant protection and mineral delivery for cell renewal
- Any condition where skin penetration matters — fulvic acids are the fraction most likely to reach deeper skin layers
The growing interest in fulvic acid in cosmetic formulations — visible in products like The INKEY List’s Fulvic Acid Cleanser — reflects the science catching up with what European spa medicine has been delivering through whole-peat applications for generations.
Evidence & Claims
Inhibits CCL17/CCL22 via p38 MAPK/JNK pathways; suppresses NF-κB activation; reduces TNF, IL-6 while preserving IL-10
Potent free radical scavenger, chelates pro-oxidant metal ions
Acts as natural chelator enhancing bioavailability of trace minerals through skin — shown to permeate human skin in vitro
Some antiviral and antibacterial activity reported, less studied than humic acids
Promotes fibroblast proliferation (3× control), angiogenesis, and wound closure; reduces inflammatory cell infiltration in wound bed
Inhibits β-hexosaminidase and histamine release from mast cells, decreases intracellular Ca²⁺ — antiallergic mechanism relevant to itch and allergic skin reactions
High chelation capacity per unit mass due to abundant carboxyl groups; acts as transport agent for trace metals in peat