Seaweed

Bladderwrack

Also known as: Fucus vesiculosus, Kelp, Rockweed, Black tang

Evidence

Iodine-rich seaweed traditionally used for thyroid support, but dose is highly variable.

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Daily target & upper limit

150 mcg / day · UL 1100 mcg

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Primary uses

Natural iodine source
Thyroid support (traditional)
Metabolic support

How it works

Natural iodine source
Also contains fucoidan
Traditional thyroid remedy
Variable iodine makes dosing difficult

Dosage

Typical range: Varies widely - often 500-1000mg providing variable iodine
Timing: Morning
With food: Either way
Duration: Monitor thyroid if using long-term
Special populations: Those seeking natural iodine source

Forms

Capsules
Tincture
Dried

Safety

Common side effects

GI upset
Metallic taste
Acne

Contraindications

Hyperthyroidism
Hashimoto's (variable)
Heavy metal sensitivity

Products containing Bladderwrack

Top-scoring supplements in our catalog that list Bladderwrack on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne

Daily Greens Plus

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Evidence notes

Variable iodine content makes dosing unreliable

Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.