Weld (Reseda luteola)
What Is Weld?
Weld is the common name for Reseda luteola, a plant of the Resedaceae family, native to the Mediterranean and western Asia. The material in circulation is aerial parts — leafy growth taken above ground. Weld is the name in everyday use, while Reseda luteola is the name that identifies it unambiguously across languages, trade documents and safety literature. Its character is described as dry hay-green, faintly bitter, which is often how the raw material is checked for quality.
Weld entered the reference literature through use rather than through chemistry. Older sources are concerned with where it grows, when it is gathered and how it is prepared, questions that still shape the material on sale today. Beyond its practical use it carries cultural associations — the yellow of Lincoln green — old craft and colour.
Today most searches for Weld come from people reading about anti aging and weight management, or checking how it sits alongside a medication they already take. The use most often documented in the literature is exceptionally high luteolin content — a well-studied anti-inflammatory flavone, followed by historic yellow dye for wool and silk since the Iron Age.
How Does Weld Work?
Weld is not a single active substance. Its chemistry is a mixture, and the fractions that researchers isolate most often are Apigenin. Apigenin is the fraction most often standardised in extracts, associated in the literature with anxiolytic flavonoid (GABA modulator).
Traditional practice described Weld in terms of taste, warmth and preparation rather than molecules — a working vocabulary that predicted which extractions were worth making long before any compound was isolated.
Published research is limited, leaning on small trials, laboratory work and animal models, and this profile cites 1 source. Reported findings centre on luteolin and luteolin-7-O-glucoside can exceed 2% of dry weight, alongside apigenin glycosides — the basis for both dye and bioactivity. Where research exists, it examines exceptionally high luteolin content — a well-studied anti-inflammatory flavone, historic yellow dye for wool and silk since the Iron Age and traditional topical use for bruises and inflammation. These are areas of study, not established outcomes, and results differ by preparation and dose.
How the plant is prepared changes what you actually get. Its constituents move readily into water — so a preparation made in another medium will not carry the same fraction of the plant, which is why traditional recipes specify one over another.
The reason Weld is treated as its own entry rather than a substitute for a related plant is proportion: related species share several of these compound classes, but not in the same ratio or concentration.
Because these constituents are processed by the same pathways that handle many medicines, Weld is documented as interacting with cyp substrates. That is a question of shared metabolism rather than of potency, and it is the main reason the plant is listed in interaction references at all.
Dose, plant part and growing conditions all shift the constituent profile, so two products carrying the name Weld can differ substantially; this is why reference entries specify aerial parts and, where they exist, standardisation markers.