Calendula: What Do We Really Know?

Calendula provides a good example of why we should distinguish between traditional use, laboratory findings and evidence from human studies.

The strongest clinical support currently concerns topical calendula preparations, particularly creams and ointments used on the skin and wounds. Research into wound healing, venous leg ulcers and certain forms of skin irritation has produced encouraging results, although not every clinical trial has found calendula superior to standard care.

Evidence for internal use is much weaker. A small clinical study reported improved healing in burn patients who received oral calendula extract, but larger and better-controlled studies are still needed. Broad claims about calendula’s systemic antioxidant, anti-inflammatory, digestive or immune effects therefore go beyond what has been firmly demonstrated in humans.

The same caution applies to calendula essential oil. Although laboratory research has identified interesting antimicrobial and antifungal properties, there is far less human clinical evidence for the essential oil than for calendula creams and ointments.

For calendula, the clearest message from current research is therefore simple: the strongest evidence is on the outside, not the inside.