Written by the Plenthera team (trained in orthomolecular nutrition). Scientifically reviewed in May 2026. Last updated: 22 September 2026.

Algae and green powders are among the most nutrient-dense foods per gram. Chlorella (50-60% protein, high chlorophyll, iron, biologically active B12 in variable amounts), spirulina (a blue-green cyanobacterium with 55-70% protein and phycocyanin), kelp (rich in iodine), barley grass (chlorophyll, fibre, minerals). Always choose brands that lab-test every batch for heavy metals — algae and seaweeds absorb them from their growing environment.

On this page: Our algae and greens categories · What is the difference between chlorella and spirulina? · Frequently asked questions · Combine with · Sources

Our algae and greens categories

• Chlorella — green freshwater alga with a high chlorophyll and protein content
• Spirulina — blue-green cyanobacterium, 55-70% protein, phycocyanin
• Chlorella + Spirulina Combo — the two combined in raw & organic tablets from Big Food
• Algomed — German chlorella specialist with its own glass-tube production
• Plantforce Chlorella — organic chlorella supplement from the Danish brand Plantforce
• Seaweed — Sea Kelp and Irish Sea Moss — natural sources of iodine
• Moringa — leaf powder with a broad nutrient profile
• Greens Blends — ready-made blends of algae, grasses and vegetables
• Astaxanthin (Vitals Astamax) — carotenoid from the microalga Haematococcus pluvialis, in softgels

What is the difference between chlorella and spirulina?

Chlorella is a green single-celled freshwater alga with a tough cell wall — which is mechanically broken to make it digestible. High in chlorophyll and iron; being studied for binding heavy metals in the gut. Contains biologically active B12, in an amount that varies per batch — which is why it is not a reliable source of B12.

Spirulina is technically not an alga but a cyanobacterium. High in protein (55-70%), phycocyanin (a blue pigment protein studied for its antioxidant properties), B vitamins and iron. Dark blue-green colour, distinctive taste. Contains only pseudo-B12.

Frequently asked questions

Does chlorella contain heavy metals?

It can — algae pick up metals from their growing environment. So always choose a brand with a Certificate of Analysis (lab report) per batch. The selected brands respect the EU limits for lead, cadmium, mercury and arsenic (Regulation (EU) 2023/915).

Does chlorella bind heavy metals?

Animal studies show that chlorella can bind heavy metals in the gut; human data is limited. A "detoxifying effect" has not been scientifically demonstrated — the body has its liver and kidneys for that. As a wholefood addition with chlorophyll and iron, chlorella remains interesting.

Is spirulina a good source of B12?

No. Spirulina contains B12 analogues that are not biologically active in humans. Vegans should take a separate methylcobalamin or cyanocobalamin supplement (advice from the Netherlands Nutrition Centre). Chlorella is also not a reliable source because of the varying amount.

How do I use algae and greens?

Start with 1-3 g per day and build up to 5-10 g. Mix into a smoothie or fruit juice (the taste is distinctive). Timing is flexible; if you have a sensitive stomach, take with a meal.

Can I take chlorella during pregnancy?

If in doubt, always consult your GP or midwife. Always choose a lab-tested brand; avoid algae products without heavy-metal certification.

What is a greens blend?

A ready-made blend of several algae, grasses (barley, wheat, alfalfa grass), vegetable powders and sometimes mushrooms — for those who want the broadest nutrient profile in a single scoop.

Combine with other categories

Algae and greens fit broadly into a wholefood approach:

• Superfoods & Mushrooms — the main category
• Greens Blends — for complete blends
• Proteins & Meal Replacements — to combine greens in shakes
• Iodine — iodine contributes to the normal production of thyroid hormones and normal thyroid function
• Vitamin C — vitamin C increases iron absorption from algae
• Vitamins & Supplements — for specific supplementation beyond greens

Sources & references

• Netherlands Nutrition Centre (Voedingscentrum) — algae, chlorella, spirulina and vitamin B12
• Merchant R.E. & Andre C.A. (2001) — A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa (Altern Ther Health Med)
• Karkos P.D. et al. (2011) — Spirulina in clinical practice: evidence-based human applications (Evid Based Complement Alternat Med)
• Regulation (EU) 2023/915 — maximum levels of lead, cadmium, mercury and arsenic in foodstuffs (replaces Regulation (EC) 1881/2006)
• Regulation (EU) 432/2012 — authorised health claims (iron, iodine, vitamin C)

Disclaimer: This text is for informational purposes only and does not replace medical advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. If in doubt, always consult your doctor or an orthomolecular therapist.