Limited evidenceMen's health

Ecklonia Cava

A brown seaweed rich in phlorotannins. The small human trials that exist are about blood lipids and blood sugar, not erectile function, and they are all small and mostly from one country.

Evidence last reviewed: August 2026

What the science says

Blood lipids Limited evidence
A 12-week double-blind trial in 97 overweight Korean adults found small reductions in total and LDL cholesterol with Ecklonia cava polyphenols. A systematic review of marine algal polyphenols in humans judged the overall body of evidence too small and heterogeneous to draw firm conclusions.
Blood glucose Limited evidence
A 12-week double-blind randomised trial of a dieckol-rich extract in pre-diabetic adults reported lower post-load glucose and insulin. It was a single small trial and has not been independently replicated.
Erectile function Limited evidence
Despite frequent marketing claims, a PubMed search returns no human trial of Ecklonia cava for erectile dysfunction. The claim rests on mechanistic reasoning about nitric oxide, not on clinical data.

Dosage & safety

Studied doseHuman trials used 72–144 mg/day of polyphenol-standardised extract for 12 weeks. Commercial capsules commonly supply 100–400 mg of extract daily.

SafetyWell tolerated in the short trials conducted, which lasted only 12 weeks. As a seaweed it can carry iodine and, depending on source, heavy metals; people with thyroid disease should be cautious. No data in pregnancy or in children.

Scientific references

Effects of 12-week oral supplementation of Ecklonia cava polyphenols on anthropometric and blood lipid parameters in overweight Korean individuals: a double-blind randomized clinical trial
Shin HC, Kim SH, Park Y — Phytother Res, 2012
Efficacy and safety of a dieckol-rich extract (AG-dieckol) of brown algae, Ecklonia cava, in pre-diabetic individuals: a double-blind, randomized, placebo-controlled clinical trial
Lee SH, Jeon YJ — Food Funct, 2015
Do marine algal polyphenols have antidiabetic, antihyperlipidemic or anti-inflammatory effects in humans? A systematic review
Murray M, Dordevic AL, Bonham MP — Crit Rev Food Sci Nutr, 2018

Where to buy

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