Dulse Capsules

THE VERDICT (INTERNAL QUALITY SCORE):

Grade A Wild-Harvest. This lot of Atlantic dulse (Palmaria palmata) was wild-harvested and sun-dried on the Bay of Fundy coast of Atlantic Canada (bay center 45.00°N, 65.75°W), where the lowest tides of each month, around the full moon, expose the dulse beds to air and sun. Its deep red-purple matches what Fundy harvesters grade as food quality, and the heavy metal panel on the certificate of analysis (COA) for these capsules passed. The COA lists no iodine figure, so we print none.
– Back To Your Roots Herbs Research Group

SENSORY ANALYSIS:

• Look: Fine, matte dulse powder in deep red-purple, closer to dried beetroot than to kelp green, with a faint sparkle of sea salt. Pull one of the veg caps apart, and the grind is even, with no filler specks.
• Smell: Clean low tide. Briny, then a soft smoky edge, the note behind the dulse nickname “bacon of the sea.” No fishy seaweed off-notes.
• Taste: Salty, savory, then a long umami finish from glutamic acid (the amino acid behind MSG) and aspartic acid. This dulse is gentler than the kelp and brown seaweed powder samples we have tasted.

HOW DOES ATLANTIC DULSE SEAWEED WORK?

• The Herb: Palmaria palmata, sold as Atlantic dulse, sourced from the Bay of Fundy, Atlantic Canada. A red seaweed of North Atlantic intertidal rock.
• The Mechanism: Acts as a whole-food sea vegetable, not an isolated nutrient. Published analyses of dulse report naturally occurring iodine, which the body needs to make thyroid hormones (NIH iodine fact sheet), along with protein, potassium, xylan, and lipids led by EPA. Amounts vary by harvest, and the COA for these dulse capsules lists none.
• The Evidence: Research by Allsopp et al. (2016) found that bread providing 5 g a day of dulse raised TSH, CRP, and triglycerides in healthy adults versus control, though all stayed within normal clinical ranges (randomized dulse seaweed trial in healthy adults, PMID 26254196). Dulse seaweed is biologically active, so the dose of each capsule matters.

Palmaria palmata: A Red Alga in the Rhodophyta Division

Dulse is not a land plant but a red seaweed, kin to nori and Irish moss. The word dulse comes from the Gaelic duileasc, and it sells as dillisk in Ireland and söl in Iceland. Mouritsen et al. (2013) trace its food use from Ireland and Brittany to Iceland, Maine, and Nova Scotia.

Dulse Seaweed Nutrients, by the Gram

Published ranges from studies that include this seaweed species, not a label for this lot.

Protein, Glutamic Acid and Aspartic Acid

Maehre et al. (2014) measured 34 to 123 g of protein per kg dry weight across ten Norwegian seaweeds and rated whole P. palmata the best cereal alternative (Norwegian seaweed protein and mineral study). Glutamic and aspartic acid drive its umami taste (Maribu et al. 2025). In lab digestion tests, tough cell walls and fiber, possibly xylan, limited how well raw dulse protein digested (Marrion et al. 2003, PMID 14609091).

EPA-Led PUFA, Not DHA, in Trace Amounts

Fat is low, about 1% of dry weight in farmed dulse, so a serving holds only trace lipids. Within that fat, EPA leads the fatty acids (dulse polar lipid analysis, Lopes et al. 2019), and the two red seaweeds in the Maehre study carried 32 to 34% long-chain omega-3s. An EPA story, not a DHA story, and a small one.

Xylan, a Soluble Fiber

Brown kelps build cell walls with alginate. Dulse uses xylan, described as abundant, water-soluble, and lignin-free (Coelho et al. 2025, PMID 40863619).

R-Phycoerythrin and Mycosporine-Like Amino Acids

R-phycoerythrin, the red pigment-protein of red algae, is extracted from dulse in research labs (Le Strat et al. 2023, PMID 37504924). Wild Grand Manan dulse also carries UV-absorbing mycosporine-like amino acids, mostly porphyra-334 and palythine (Athukorala et al. 2016, PMID 26805798).

Lab Note: Deep Red Color Is a Grading Cue

Grand Manan graders sort dried dulse by color and pack the deepest red fronds for food, so color is worth checking in any bottle of dulse powder or seaweed capsules.

Iodine Compared: Palmaria vs. Saccharina Kelp and Alaria

Here is a number worth checking on any seaweed supplement: 32 mg of dry Saccharina kelp, 283 mg of Alaria, or 2,149 mg of Palmaria met the daily iodine recommendation for most healthy adults (North Atlantic seaweed iodine study, Roleda et al. 2018). Gram for gram, that kelp ran about 67 times higher in iodine than dulse. Why care? Some seaweed supplements pass the iodine upper limit in a single dose (Aakre 2021).

Iodine Shifts With Season and Storage

Dulse is not a fixed iodine dose. Arctic P. palmata held 650 to 1,450 mcg of iodine per gram, highest in spring and summer, which limited intake to no more than about 0.4 to 0.9 g of dry dulse a day for a 70 kg adult under the European upper limit of 600 mcg (seasonal dulse composition study, Maribu et al. 2025). Wild dulse from Atlantic Canada tested far lower, at 30 to 107 mcg per gram (Lafeuille et al. 2023). Which figure fits this seaweed? Only a lot assay can say. Iodine can also vaporize in humid storage (Teas et al. 2004, PMID 15588380). Our lot COA lists no iodine figure, so treat the 2-capsule daily cap as a ceiling, not a target.

Dulse Powder vs. Seaweed Extract: Why We Encapsulate the Whole Thallus

An extract keeps what its solvent pulls out. Whole dulse powder keeps fiber, pigment, protein, lipids, and minerals together, and Maehre et al. (2014) rated whole P. palmata the best cereal alternative while suggesting extraction only for several other species. What is inside each capsule? Each of our dulse capsules holds 500 mg of milled whole thallus. No seaweed extract, no rice flour, no gelatin. Oven drying at 40 °C changed the minerals of wild Quebec dulse only modestly, though sun-drying was not tested (Atlantic Canada dulse drying study, Lafeuille et al. 2023).

Why Bay of Fundy Tides and Sunlight Matter

The Bay of Fundy has the highest tidal range in the world, and its lowest tides of the month, around the full moon, expose dulse beds to open air and sun (Bay of Fundy location map). What does that sunlight change? Grand Manan dulse from the higher-UV coast showed higher reducing activity in one lab extract (Grand Manan dulse antioxidant study, Yuan et al. 2005), a test-tube finding about the seaweed, not a promise about this lot or your body.

Grand Manan Island and the Dark Harbour Harvest

Dark Harbour on Grand Manan was the early-1900s dulse capital of the world, where pickers worked by hand at low tide and dried fronds on sun-warmed rocks (history of dulse in New Brunswick). A 1990 Fisheries and Oceans Canada report on southwest New Brunswick fisheries describes the same lowest-tide picking of Grand Manan dulse, and dried dulse now fetches more per pound than lobster (MOFGA account of the Grand Manan dulse harvest). The dulse in these capsules comes from this Bay of Fundy seaweed coast.

CRITICAL USAGE: DOSE, IODINE AND MEDICATION SAFETY

Suggested Use: Take 2 vegetable capsules (about 1,000 mg of dulse powder) once daily with food. Do not exceed 2 dulse capsules per day.

New to Seaweed? Start with 1 capsule daily for the first week. If your stomach objects, drop back or stop.

Prefer Food? Open the capsules and sprinkle the seaweed powder over soup or eggs. It still counts toward your daily serving.

Count Your Iodine: Add this seaweed supplement (2 capsules) to iodine from iodized salt, dairy, eggs, multivitamins, and other seaweed capsules. The adult upper limit is 1,100 mcg a day from all sources (NIH Office of Dietary Supplements).

Storage: Keep the capsules tightly closed in a cool, dry, dark place. Use by the expiration date. Keep out of reach of children.

Who Should Check With a Doctor or Pharmacist First?

Thyroid Conditions and Thyroid Medication

Excess iodine can push susceptible people, including those with thyroid disease, into hypothyroidism or hyperthyroidism (review of excess iodine and thyroid function, Leung and Braverman 2014). With thyroid disorders or thyroid medication, ask your prescriber before starting dulse seaweed.

Other Cautions for Dulse: Warfarin, Kidney Disease, Pregnancy, Shellfish

Seaweeds carry vitamin K (Mouritsen et al. 2013 measured it in dulse), so on warfarin, ask your prescriber first. Dulse also carries potassium and sodium (Lafeuille et al. 2023), so with kidney disease, ask your nephrologist. Pregnant or nursing? Iodine needs change, so talk with your provider. Wild seaweed shares the shoreline with shellfish, so check with your doctor if you have a shellfish allergy.

Important: As with any dietary supplement, consult your healthcare provider before use if you take prescription medications or have a medical condition.

CLINICAL SPECS:

Spec	Detail
Serving Size	2 Vegetable Capsules (~1,000 mg) | 30 Servings per Bottle
Frequency	Once daily with food (do not exceed 2 capsules per day)
Active Marker	Naturally Occurring R-Phycoerythrin, Xylan, Iodine, and EPA-Led Lipids (Amounts Not Listed on the COA)
Processing	Wild-Harvested, Sun-Dried, Milled Whole Thallus
Safety	Heavy Metal Tested (Pass)
Ingredients	100% Palmaria palmata (Dulse) Whole Thallus Powder
Other Ingredients	Vegetable Cellulose (Capsule)
Purity	Vegan, Wild-Harvested (Not Certified Organic)
Free From	No Added Wheat, Gluten, Soy, Dairy, Binders, or Fillers
Origin	Bay of Fundy, Atlantic Canada (Bay Center 45.00°N, 65.75°W)
Manufactured	Virginia Beach, VA, USA (Encapsulated From Canadian Dulse)

DULSE SUPPLEMENT vs. GENERIC SEAWEED EXTRACT BLENDS:

Some seaweed capsules blend several species, or use an extract instead of the whole frond. Our dulse capsules carry one species, one origin, whole.

Feature	BTYRH Dulse Capsules	Generic Seaweed Supplement
Origin	Bay of Fundy, Atlantic Canada (bay center 45.00°N, 65.75°W)	Often Unspecified
Preparation	Sun-Dried Whole Thallus in Vegetable Capsules, Single Species (Palmaria palmata)	Often a Mixed-Species Blend or Seaweed Extract
Taste	Briny-Umami With a Faint Smoky Note	Varies by Species and Blend
Safety	Heavy Metal Tested (COA), Iodine Variability Disclosed	Unknown/Untested Unless a COA Is Shared

Building a sea vegetable shelf? See our Gigartina red marine algae capsules, our sea moss capsules, or our guide to spirulina and chlorella benefits.

FREQUENTLY ASKED QUESTIONS ABOUT DULSE SEAWEED AND IODINE

How much iodine is in a 1,000 mg serving?

We will not guess. The lot COA lists no iodine figure, and published dulse values differ widely between studies, from 30 to 107 mcg per gram in Atlantic Canada to 650 to 1,450 mcg per gram in the Arctic (Lafeuille 2023, Maribu 2025). Count these dulse capsules toward your daily iodine total.

Flakes or whole leaf: why encapsulate at all?

Grocery-aisle flakes and whole leaf dulse shine in the kitchen, but a sprinkle is hard to measure, and the smoky taste is not for everyone. Our veg caps give a fixed 500 mg of whole dulse powder with little or no taste, and capsules travel well.

Are arsenic and other heavy metals a concern in red seaweeds?

Seaweeds pull elements from seawater, so testing matters. The CFIA inorganic arsenic and seaweed guidance flags hijiki as high and reports low results for dulse, nori, and kombu samples. This lot of capsules passed the heavy metal panel on its COA.

Is this sea vegetable certified organic?

No. Our dulse is wild-harvested and sun-dried but not certified organic, so we never call these organic dulse capsules. Questions about a lot? Message @backtoyourherbs on X (Twitter).

What side effects can too much iodine from sea vegetables cause?

Too much iodine can disturb thyroid function, especially in people with thyroid disease, older adults, and infants. In a 96-product market survey, seaweed supplements ran from 5 to 5,600 mcg of iodine per daily dose (analysis of 96 kelp and seaweed products, Aakre et al. 2021). That spread is why we stop at 2 capsules a day.

Can I take it with a thyroid condition or thyroid medication?

Ask your prescriber before taking these capsules. In the Allsopp trial, TSH rose 17.2% versus control in healthy adults eating 5 g of dulse a day, though values stayed in the normal range.

How is dulse different from kelp?

Dulse is a red seaweed. Kelp is a brown seaweed. Saccharina kelp carried roughly 67 times more iodine than dulse, gram for gram (Roleda 2018). Dulse tastes salty and smoky; kelp tastes sharper.

What are the health benefits of this sea vegetable?

Dulse is food first. Studies of the species report iodine, potassium, protein, xylan fiber, EPA-led lipids, and the red pigment phycoerythrin, in amounts that vary by harvest. Human research is thin and tracked blood markers, not health outcomes. These dulse powder capsules suit adults who want seaweed nutrition without the flavor.

How does this compare with a liquid dulse extract?

Liquid extracts keep only what dissolves in their solvent and discard the rest of the frond, and their iodine content depends on the process. Before buying any dulse extract or capsule, ask the seller, us included, for lot test results. Our Atlantic dulse capsules stay whole, from tide line to capsule.

DISCLAIMER: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.