PlainPill

Kelp

People mainly take Kelp for energy, focus, mood. Based on 10 first-hand reports and 10 meta-analyses & systematic reviews in the medical literature. Ranked #640 of 1,974 overall.

23
User score
Mostly positive
30% positive0% mixed0% negative70% unclear

Of reports that state an outcome, 100% are positive.

Clinical research
BModerate research base
10
meta-analyses
5
RCTs
2,019
papers

What Kelp does, according to users

Of the people who reported each effect, the share who said it got better.

What the research says

Systematic reviews and meta-analyses from PubMed, with their published conclusions.

BModerate research base

At least one meta-analysis, or 5+ randomized controlled trials. The grade measures how much human research exists — read the conclusions below for what it found.

Ann Bot · 2024 · Meta-analysis / systematic review
Temperature sensitivity of detrital photosynthesis

Conclusion: T opt of kelp detritus is ≥3 °C colder than that of the intact plant. Given that E. radiata is one of the most temperature-tolerant kelps, this suggests that photosynthesis is generally more thermosensitive in the detrital phase, which partly explains the enhancing effect of temperature on remineralization. In contrast to darkness, even subcompensating irradiance maintains detrital viability, elucidating the accelerating effect of depth and its concomitant light reduction on remineralization to some extent. Detrital photosynthesis is a meaningful mechanism underlying at least two drivers of re

PubMed 38142363 ↗
J Hum Nutr Diet · 2025 · Meta-analysis / systematic review
Edible Algae Reduce Blood Pressure in Humans: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Conclusion: Consuming over 3 g/day of whole edible algae, especially Spirulina, for at least 12 weeks significantly lowers BP, particularly in those with elevated levels. This suggests that edible microalgae may serve as a natural approach to managing hypertension, complementing pharmacological treatments.

PubMed 40726022 ↗
Proc Natl Acad Sci U S A · 2013 · Meta-analysis / systematic review
Recovery of a top predator mediates negative eutrophic effects on seagrass

Conclusion: In a study of seagrass beds in an estuarine ecosystem exposed to extreme nutrient loading, we use a combination of a 50-y time series analysis, spatial comparisons, and mesocosm and field experiments to demonstrate that sea otters (Enhydra lutris) promote the growth and expansion of eelgrass (Zostera marina) through a trophic cascade, counteracting the negative effects of agriculturally induced nutrient loading. Our results add to a small but growing body of literature illustrating that significant interactions between bottom-up and top-down forces occur, in this case with consequences for the

PubMed 23983266 ↗

Dosage people report

As stated by users — not a recommendation. Follow the label or your doctor.

750-1000 mcg iodine equivalentdaily
325 mcgas reported
150 mcgdaily

Reported side effects

How often each side effect came up across all reports.

No side effects reported so far.

What users say

Verbatim quotes, shortened only — each links to the original discussion.

“Kelp (most biocompatible form of Iodine / halides detox)”
Source discussion ↗
“a Kelp-based product, kelp contains the most biocompatible form of Iodine”
Source discussion ↗
“Is iodine from kelp good to go? That's all I have”
Source discussion ↗
“I decided to purchase an Iodine supplement in the form of Kelp/Seaweed...after the short detox period was over; my whole life changed!”
Source discussion ↗
“Kelp - low iodine. 325mcg of Kelp. I've read dosages should be between 600-1100mcg.”
Source discussion ↗
Top discussions (5)

Other options for energy

User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate