Last verified: 20 days ago
Nori Leaf
Also known as: Porphyra umbilicalis, Porphyra yezoensis, laver, purple laver, nori seaweed
Evidence under review. — Not yet rated
Seaweed-derived ingredient with traditional use; no clinical trial data available to confirm supplement benefits.
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What it does
Nori is a type of edible red algae (seaweed) most commonly known as the thin sheets used to wrap sushi. As a whole food, nori contains vitamins B12, A, and C, iodine, iron, and some protein. In...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
No established dose
What the Science Says
Nori is a type of edible red algae (seaweed) most commonly known as the thin sheets used to wrap sushi. As a whole food, nori contains vitamins B12, A, and C, iodine, iron, and some protein. In supplement form, nori leaf extract is marketed for thyroid support, antioxidant activity, and general nutritional support, but these claims are based on its nutritional composition as a food — not on clinical trials testing it as a supplement ingredient.
What It Doesn't Do
No clinical evidence it boosts thyroid function in healthy people. Not proven to aid weight loss. No demonstrated detox effects. Eating nori in sushi is not the same as taking a concentrated supplement — the two are not interchangeable. No proven cognitive or energy benefits from supplement doses.
Evidence-Based Benefits
Nori is a type of edible red algae (seaweed) most commonly known as the thin sheets used to wrap sushi. As a whole food, nori contains vitamins B12, A, and C, iodine, iron, and some protein. In supplement form, nori leaf extract is marketed for thyroid support, antioxidant activity, and general nutritional support, but these claims are based on its nutritional composition as a food — not on clinical trials testing it as a supplement ingredient.
Weak EvidenceEffective at: No established dose
Source: auto-research
Absorption & Bioavailability
Unknown — no clinical pharmacokinetic data available for nori leaf in supplement form. Iodine from seaweed is generally well absorbed, but absorption of other compounds is not well characterized.
Red Flags to Watch For
- Zero indexed clinical trials in PubMed — any health claims on product labels are not backed by human study data
- High iodine content in seaweed-based products can disrupt thyroid function, especially with regular high-dose use
- Despite 1,000+ registered supplement products containing this ingredient, widespread commercial use does not equal proven efficacy
- Marketing as a 'superfood supplement' often overstates benefits beyond what eating nori as a food would provide
- People with thyroid conditions or iodine sensitivity should consult a doctor before use
Products Containing Nori Leaf
See how Nori Leaf is used in these analyzed products:
Research Sources
- General knowledge
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-02