Benefits
Traditional European tea for digestive complaints
In Germany, lady's mantle herb is sold as an authorized medicinal tea whose leaflet lists support in the care of mild, nonspecific diarrhea in adults and school children, and the ESCOP monograph summary lists nonspecific diarrhea and gastrointestinal complaints as its indications. This rests on long-standing use and the herb's tannin content; no trial in people has tested it.
Rich in astringent ellagitannins such as agrimoniin
Analyses of the leaves and flowering tops found ellagitannins such as pedunculagin and agrimoniin as the main phenolic compounds, rising later in the flowering season. In 16 batches of dried Alchemilla xanthochlora herb, tannins averaged 16.0% and total flavonoids 2.22%. Tannins are the basis of its traditional astringent use.
Tannins converted to urolithins by gut bacteria in lab tests
When a lady's mantle herb extract was incubated with stool samples from three healthy donors, 33 breakdown products were detected, and the sample from one donor contained urolithin C, a gut-made compound studied in its own right. Agrimoniin, a main tannin of the herb, is known to be broken down this way. This is lab work with stool samples, not a study in people.
Hormone and ovary effects in an animal model
Lady's mantle has a long folk history as a women's herb. In female rats given the hormone DHEA to mimic polycystic ovary changes, an oral extract (50 mg per 100 g body weight daily for 35 days) was reported to return hormone levels, ovary structure and blood vessel function toward control values. No human study has tested this.
Stomach lining in a rat model, as part of a juice blend
In rats given the painkiller indomethacin, 10 days of an aronia juice blended with lady's mantle reduced stomach lining damage, and it had the highest polyphenol content and the strongest effect of four aronia juices tested. The blend, not lady's mantle alone, was tested, and only in animals.
Mechanism of action
Astringent tannin content
Reviews describe lady's mantle as astringent because of its tannin content, which is high among rose family plants (one survey of 42 species placed it with the most tannin-rich). Astringent tannins are the traditional rationale for its use as a tea for loose stools; this has not been measured in people.
Gut bacteria turn ellagitannins into urolithins
Agrimoniin and related ellagitannins are broken down by human gut bacteria into smaller compounds called urolithins, which have their own activity in lab and animal studies. Stool incubation of a lady's mantle extract produced urolithin C in one of three donors, so conversion may vary from person to person.
Clinical trials
Open, uncontrolled human study of Weighlevel, a 310 mg tablet with 60 mg lady's mantle leaf plus olive leaf, wild mint and cumin, one tablet 30 minutes before each of three meals for 3 months, by authors from the herbal company that prepared the extracts, alongside lab and animal tests (Said et al. 2011, Evid Based Complement Alternat Med)
80 adult volunteers with a mean BMI of about 30.7; 14 were excluded for not following the protocol, leaving 66 analyzed.
BMI fell from 28.5 to 24.5 in overweight and from 32.1 to 27.5 in obese participants over 3 months, and no side effects were reported. There was no placebo group, participants were also told to eat only three meals a day, and lady's mantle was one of four herbs, so the result cannot be credited to lady's mantle.