Best Sea Greens Supplements

Best Sea Greens SupplementSea greens are densely nutritious edible algae that grow throughout the world’s oceans.

The term “greens” is a bit misleading – they come in a range of greens, browns, purples and even black.

Other names are technically incorrect too:

algae aren’t “sea vegetables”, nor are they “sea weeds” – there’s nothing plant-like about these algae.

Instead, they’re a collection of photosynthetic organisms that don’t fall into any other categories, but like many plants they are packed full of nutrients and phytochemicals that support human health.

Sea greens often have a higher concentration of key essential nutrients than any plant could ever manage, making them a useful addition to boost your health and performance.

There are hundreds of species of edible sea greens from all across the world.


Don’t worry – we’ve rounded up the most nutritious, delicious and readily available sea greens for you:

Nori – Japanese Red Algae Seaweed

Vitamin C, magnesium, calcium

Nori is more than the wrapper than keeps your sushi rolled up tight – it can also protect your cardiovascular system.

  • One animal study showed that eating nori could increase levels of the antioxidant glutathione in the liver, and another showed that nori is particularly effective at reducing cholesterol levels [14].

In terms of nutrients, nori is a good source of vitamin C, magnesium, calcium, iron and folate. However, it has very little iodine compared to other sea greens – but this is good news for some, making it a safe marine vegetable for people with high thyroid function (but speak to your nutritionist first!).

While nori contains high levels of vitamin B12, vegans shouldn’t rely on it to keep their levels up – this algae also contains peptides that bond to the B12 and stop the body from being able to absorb much of it. On the other hand, nori is a fantastic source of bioavailable plant-based iron!

Wakame – Soup and Salad Staple Point

Fucoxanthin, Calcium & Magnesium

Wakame contains a high concentration of fucoxanthin, a rare antioxidant that has a unique molecular structure with multiple unstable bonds. This gives it incredibly high antioxidant activity to protect against cellular damage and promote proper metabolic function.

In fact, fucoxanthin has been shown to have anti-obesity, anti-inflammatory, anti-cancer and liver protective actions [2]…

And this is just one nutrient found in wakame!

This sea green is also rich in calcium and magnesium, and has been shown to regulate blood pressure, reduce cholesterol, and regulate blood sugar [3] [4] [5].

Dulse – Red Sea Lettuce

Iodine, Low sodium

Dulse, also known as purple or brown sea lettuce, has particularly high protein content for a sea green.

Researchers are looking at all aspects of dulse for its use as a functional food – it appears to contain a unique antioxidant that may fight against cancer [11], a protein that reduces hypertension [12], and an excitatory neurotransmitter to fires up the brain [13].

Dulse also has the added bonus of being lower in sodium than other sea vegetables – great if you’re watching your blood pressure!

Kelp – The Classic Thyroid Booster

Iodine, Potassium & Thyroid Stimulation

Like most sea vegetables, kelp contains iodine – an essential nutrient for thyroid health and function. However, kelp seems to have a particular affinity for the thyroid that goes way beyond supplying adequate iodine.

  • A 2003 study looked at how taking kelp supplements can affect the levels of thyroid stimulating hormone (a biomarker of thyroid function). Participants who took kelp capsules for 4 weeks had a significant increase in thyroid stimulation, suggesting that taking kelp can initiate and boost thyroid function [7].

This is great news for people with sluggish thyroid activity – but those with an overactive thyroid should be cautious about taking kelp or other sea greens in large doses.

Bladderwrack – Fucoxanthin Rich Seaweed

Fucodians & Iodine

Like kelp, bladderwrack can directly stimulate thyroid function (for better or for worse… take with caution if you have a hyperactive thyroid!) [8]. It also contains a high level of fucodians – unique polysaccharides found in many sea vegetables, that have been shown to have immune modulating, anti-cancer, and anti-viral actions [9].

Research shows that the fucodians derived from bladderwrack are the strongest and most potent in the body, with a particularly strong action against breast cancer and viral infections [10].

Kombu – The King of Seaweeds

Iron, Glutamic Acid & Iodine

Kombu is a rich source of iron, as well as glutamic acid – this is the amino acid that is responsible for the “umami” or uniquely savoury flavour often found in Japanese cuisine. It is also responsible for an excitatory or stimulating effects on the brain that can support a stable and happy mood.

Kombu is also rich in iodine – so much so, that excessive consumption can cause iodine toxicity [1].

As a very fibrous algae, kombu has been shown to prevent the absorption of dietary fat and, like wakame, it contains fucoxanthin which may help to boost weight loss efforts [2].

Sea greens are easy to include in the diet. Because they are so nutrient-packed, a little goes a long way – it’s easy and tasty to include dried, pickled, powdered or fresh sea vegetables in soups, salads, and of course sushi.

However, if you’re looking for therapeutic doses or measurable nutrient support, go for a supplement.

Most sea greens are harvested by hand and sun-dried to maintain their nutrient levels, then powdered and packed into capsules. This approach retains as many of the natural enzymes, peptides and found in living algae. Many sea greens are the available in solo supplemental forms, but if you’re looking for a broad range of nutrients, go for a combination supplement.

Here are our top 5 picks, available now on Amazon:

The 5 Best Sea Greens Combination Supplements

5. Emerald Essentials Emerald Sea (90 capsules)

Sea Greens SupplementAll of the seven organic species of sea vegetables in this product are hand-harvested from cold Northern Atlantic waters and sun-dried to retain maximum nutrient content. The blend of Norwegian kelp, kombu, dulse, bladderwrack, sea lettuce, wakame and nori is certified organic and packaged with no additives – no added nutrients, synthetics or hidden ingredients here. This is a great choice if you’re looking for a high potency blend of true super foods.

4. Swanson Green Foods Seaweed Vegetable Complex (60 capsules)

Seaweed SupplementsIf you’re looking for a standardised iodine or fucoidan extract dose, this is the perfect choice – each vegetable capsule contains 400mcg of iodine from Atlantic kelp, and a standard 100mg of fucoidan extract, along with with dulse, spirulina, chlorella, Irish moss and red algae to create a broad multi-nutrient supplement. Swanson have all plants tested before production for pollutants and heavy metals.

3. Seatrition Daily Ocean Blend (180 capsules)

Sea TritionSeatrition have combined twelve varieties of sea greens and algae including dulse, sea lettuce, bladderwrack, nori and kombu to create a broad-spectrum multivitamin alternative. They source their greens from waters across the world in Ireland, France, Iceland and Asia, and guarantee that they are tested for radiation, mercury, and any other heavy metals and pollutants. No fillers, additives or binders here! This is a great choice if you’re looking for an ocean-derived multivitamin that is clean, vegan-friendly, and packs 300mcg of vegetable iodine per capsule!

2. Sea of Greens®

Sea of GreensSea of Greens is a registered trademarked blend of sea vegetables with spirulina and chlorella algae in an easy-to-swallow vegetable-capsule. The big players are all here – wakame, sea lettuce, dulse and bladderwrack – in a non-GMO, organic blend. As a wholefood supplement, amounts of nutrients will differ between each capsule and each product but the variety of sea greens in this product is rich in a wide range of essential vitamins and minerals.

1. Potent Sea Sea Vegetables (90 capsules)

Sea Vegetables SupplementPotent Sea isn’t just a very pun-ny brand name – their products really do pack a lot of potency. Their Sea Vegetables blend contains a hand-harvested and sun-dried combination of sea greens that has been formulated to deliver broad spectrum nutritional requirements for healthy thyroid function and blood sugar control. With powdered dulse, bladderwrack, rockweed, kombu and sea lettuce, each capsule contains decent levels of key nutrients, including 266mg of fucoidans and 5mg of magnesium.

See Potent Sea On Amazon

Further Reading:


About James Lyons

James Lyons (BHSc Nutritional Medicine) is a clinical nutritionist, medical writer, and educator. He specialises in plant-based nutrition and is passionate about improving public access to reliable and accurate health information.

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