Equisetum arvense ~ Supplements containing extracts of Equisetum arvense – common name Horsetail – can be found in any pharmacy or health food shop. They are said to strengthen hair, skin and nails. According to Brazilian researchers they are also excellent diuretics: Equisetum arvense even works better than the diuretic hydrochlorothiazide.
Equisetum arvense contains relative large amounts of silicon, which according to the manufacturers is good for hair growth. The plant also contains phenols, such as caffeic acid and flavonoid compounds, and also substances such as equisetumosides and equisetumpyrones. These are probably responsible for the healing properties attributed to Equisetum arvense. The plant is one of the most widely used medicinal herbs in the world.
The Brazilians wanted to know more about the diuretic effects of Equisetum arvense. While the effects are reported in many handbooks, there were no scientific studies to confirm – or refute – these.
The diuretic effect of Equisetum arvense is probably also the reason that extracts of the plant are often found in slimming teas or supplements: these products increase the amount of liquid that users lose in their urine, thus leading to weight loss.
Users think they are losing fat, but much of the weight they lose actually consists of liquid. As soon as the slimmers stop taking the supplements the kilos pile back on again.
The researchers performed an experiment with 36 healthy subjects aged 20-55. Three times a day they took either a placebo, or 25 mg hydrochlorothiazide [structural formula shown below] or 900 mg Equisetum arvense extract.
When the subjects took the extract this was divided over 3 intakes of 300 mg each day. The researchers used a product manufactured by the Brazilian Artesanal Pharmacy. The extract consisted of the aboveground parts of Equisetum arvense.
The researchers measured the amount of liquid that the subjects ingested, and subtracted the amount of liquid the subjects lost in the form of urine, thus estimating the subjects’ fluid balance. The fluid balance was measured just before starting supplementation, and on the fourth and last days of administration.
The figure below shows that the diuretic effect of Equisetum arvense superseded that of hydrochlorothiazide.
The researchers found no indications that Equisetum arvense affects the sodium-potassium electrolyte balance. That doesn’t mean much as these effects were not found when the subjects took hydrochlorothiazide either. Nevertheless William Llewellyn’s Anabolics [amazon.com] states that hydrochlorothiazide does alter the body’s sodium-potassium balance: hydrochlorothiazide use leads to potassium loss.
It would seem that the Brazilian experiment was too short to lead to visible effects on the electrolyte balance.
The researchers observed no damaging effects of Equisetum arvense on either liver or kidneys.
Randomized, Double-Blind Clinical Trial to Assess the Acute Diuretic Effect of Equisetum arvense (Field Horsetail) in Healthy Volunteers.
In this double-blind, randomized clinical trial, 36 healthy male volunteers were randomly distributed into three groups (n = 12) that underwent a three-step treatment. For four consecutive days, we alternately administered a standardized dried extract of Equisetum arvense (EADE, 900?mg/day), placebo (corn starch, 900?mg/day), or hydrochlorothiazide (25?mg/day), separated by a 10-day washout period. Each volunteer served as his own control, and the groups’ results were compared. We repeated the same evaluation after each stage of treatment to evaluate the safety of the drug. The diuretic effect of EADE was assessed by monitoring the volunteers’ water balance over a 24?h period. The E. arvense extract produced a diuretic effect that was stronger than that of the negative control and was equivalent to that of hydrochlorothiazide without causing significant changes in the elimination of electrolytes. There was no significant increase in the urinary elimination of catabolites. Rare minor adverse events were reported. The clinical examinations and laboratory tests showed no changes before or after the experiment, suggesting that the drug is safe for acute use. Further research is needed to better clarify the mechanism of diuretic action and the other possible pharmacological actions of this phytomedicine.
PMID: 24723963 [PubMed] PMCID: PMC3960516