Algae

Botanical

What is it

Algae is a broad category of aquatic photosynthetic organisms. In supplements, the term covers green microalgae (chlorella), blue-green algae (spirulina, AFA), red marine algae (Lithothamnion as calcium source), and golden microalgae used for vegan EPA/DHA.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Vegan omega-3 (algae oil)

Strong Evidence

Schizochytrium-derived DHA/EPA raises omega-3 status equivalently to fish oil at equal doses.

Modest cardiometabolic effects (spirulina/chlorella)

Limited Evidence

Small RCTs show modest lipid and BP changes; results vary.

How it works

Different algae deliver different actives. Spirulina and chlorella are protein- and chlorophyll-rich whole-food supplements with modest immune and metabolic effects. Schizochytrium-derived algae oil provides vegan DHA and EPA via direct synthesis. Lithothamnion calcified red algae supply highly absorbable calcium and trace minerals. Calcareous marine algae provide alkaline buffering ions used in bone-health products.

Dosage

Spirulina: 3-10 g/day. Chlorella: 3-10 g/day. Algae omega-3: dose by EPA/DHA content (250-500 mg/day combined). Algae calcium: per elemental Ca content.

When and how to take it

Take with meals.

3 commercial forms

Compare the main delivery options and what they’re best suited for.

Spirulina

Whole-food supplement.

Blue-green algae; protein- and chlorophyll-rich.

Chlorella

Whole-food supplement.

Green microalgae; broken-cell-wall forms improve absorption.

Algae oil (Schizochytrium)

Used in vegan fish-oil alternatives and infant formula.

Source of vegan EPA/DHA.

Safety

Reputable products are safe. Concerns include heavy metal contamination (especially in wild-harvested), microcystin contamination in non-Spirulina blue-green algae, and iodine variability. Pseudoallergic reactions can occur.

Who should be cautious

Phenylketonuria (spirulina contains phenylalanine). Autoimmune disease (theoretical concern with strong immune-stimulant claims). Anticoagulants. Choose tested products.

Interactions

Chlorella and spirulina may modestly affect anticoagulation. Algae iodine may interact with thyroid medication. Algae vitamin K1 (chlorella) may affect warfarin.

Food sources

Nori (1 sheet)

Amount
minerals, B12 analog
%DV
—

Spirulina (1 tbsp)

Amount
~4 g protein, beta-carotene
%DV
—

Frequently asked questions

Is spirulina a complete protein?⌄

It contains all essential amino acids but in proportions not ideal for human needs at typical doses.

Is algae oil as good as fish oil?⌄

Yes, at equivalent EPA/DHA doses. Lower contaminant risk and vegan-friendly.

References

Algae on Wikidata — Wikidata link

Algae on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Algae (PubMed search) — PubMed link

Track Algae with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.