Ecklonia Cava: Seaweed Polyphenol Trials and Safety
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Ecklonia Cava (Brown Seaweed Extract): half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is ecklonia cava?

Ecklonia cava is an edible brown seaweed. Its extracts are rich in phlorotannins, a type of polyphenol found in brown algae, such as dieckol.

Also known as: Ecklonia cava extract, brown algae polyphenols, phlorotannins, dieckol, Seanol, brown seaweed extract.

Amounts studied

Trials used 72 or 144 mg a day of polyphenols for 12 weeks (Shin 2012), 1,500 mg a day of a dieckol-rich extract for 12 weeks (Lee 2015), and single doses before exercise, including 263 mg (Ali 2026). These are study protocols, not a recommendation.

Approval status and how it is used

The NIH Dietary Supplement Label Database lists Ecklonia cava products such as Ecklonia Cava Extract 800 mg from SuperSmart as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.

What studies show: in 97 overweight Korean adults, 12 weeks of the polyphenol extract lowered BMI, body fat, waist size and total and LDL cholesterol compared with placebo; the first author worked at Botamedi Research Center (Shin 2012). In 80 adults with prediabetes, a dieckol-rich extract for 12 weeks lowered blood sugar after meals compared with placebo (Lee 2015). For exercise, one drink before testing lengthened time to exhaustion by 2.4 minutes in 20 Korean college men (Oh 2010), but in a 2026 UK trial in 12 trained cyclists a single dose did not improve sprint power (Ali 2026). All trials were small.

Safety: the 12-week trials reported no significant side effects and normal blood tests (Shin 2012, Lee 2015). The sources here do not describe drug interactions.

Ecklonia cava half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a single published half-life or time to peak for Ecklonia cava extract that applies to a supplement dose, so we do not list one. Plant extracts are mixtures of many compounds, so no single figure would describe them.

How to track ecklonia cava in Dose Track

  1. Add ecklonia cava as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each dose when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

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Frequently asked questions

What is the half-life of ecklonia cava?+
We could not find a single published half-life or time to peak for Ecklonia cava extract that applies to a supplement dose, so we do not list one. Plant extracts are mixtures of many compounds, so no single figure would describe them.
Does Ecklonia cava help weight loss?+
One 12-week trial in 97 overweight Korean adults found lower BMI, body fat and cholesterol than placebo. It has not been confirmed in larger trials.
Can I track ecklonia cava in Dose Track?+
Yes. Ecklonia cava is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each dose next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Shin HC, et al. 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. Phytother Res. 2012;26(3):363-368.
  2. Lee SH, Jeon YJ. 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. Food Funct. 2015;6(3):853-858.
  3. Oh JK, et al. Effect of supplementation with Ecklonia cava polyphenol on endurance performance of college students. Int J Sport Nutr Exerc Metab. 2010;20(1):72-79.
  4. Ali Y, et al. Effects of acute Ecklonia cava supplementation on submaximal cycling and repeated-sprint performance in trained cyclists: a randomised double-blind placebo-controlled crossover trial. Nutrients. 2026;18(20):3430.
  5. NIH ODS Dietary Supplement Label Database. Ecklonia Cava Extract 800 mg (SuperSmart), dietary supplement label, entered May 22, 2021; checked October 28, 2026.
  6. FDA. Questions and answers on dietary supplements.

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