The claimEvidence A · guideline-tier
Spirulina = vegan B12 source
The evidence
It contains pseudo-B12, a look-alike that cannot activate the human enzymes that depend on B12 — and it may even crowd real B12 off its receptors.
The mechanism, in brief
Spirulina is not, strictly speaking, an alga. It is a cyanobacterium — the kind of microbe that rises as a film on the surface of a pond — and it belongs to a completely different family from kelp or nori.
Sources (1)
- Karkos, P. D., Leong, S. C., Karkos, C. D., Sivaji, N., & Assimakopoulos, D. A. (2011). Spirulina in clinical practice: evidence-based human applications. Evidence-Based Complementary and Alternative Medicine, 2011, 531053.