Melilotus officinalis, sweet yellow clover or melilot, is a European legume with a long history of medicinal use, mostly concerning circulation and fluid retention.
The active constituent
Sweet clover's activity is attributed largely to coumarin, which gives the dried plant its characteristic scent of new-mown hay. It also contains flavonoids and saponins.
Coumarin has documented effects on venous tone and on lymphatic drainage. In some European countries, standardised sweet clover preparations have been used medicinally for chronic venous insufficiency and lymphoedema.
How it works in skincare
Two roles.
The vascular and lymphatic activity is why it appears in products aimed at fluid retention, puffiness and the appearance of congestion, particularly around the eye.
Separately, extracts have been studied for effects on the extracellular matrix, which is why it turns up in firming formulations alongside structural peptides.
The coumarin question
Worth understanding, because two distinct things share the name.
Coumarin itself is a naturally occurring aromatic compound found in many plants, including tonka bean, cassia cinnamon and this one. It is a recognised fragrance allergen and appears on EU declaration lists when present above a threshold.
Dicoumarol is a different compound, formed when sweet clover spoils and moulds. It is a potent anticoagulant, and its discovery in mouldy sweet clover hay causing haemorrhage in cattle led to the development of warfarin.
Properly prepared sweet clover extract does not contain dicoumarol. But the historical association is real, and it is why sweet clover preparations are discussed cautiously in a medical context.
Pregnancy and medication
Given the anticoagulant association and the limited safety data for topical botanical extracts in pregnancy, this is worth confirming with your doctor. Particularly relevant if you take anticoagulant medication, where the interaction question belongs with your prescriber rather than a product page.
