What they are
Spirulina (Arthrospira platensis) is a cyanobacterium — a photosynthetic prokaryote. It is cultivated in alkaline water ponds or closed bioreactors. Despite being called a “blue-green algae,” it is taxonomically a bacterium, not a plant or algae.
Moringa (Moringa oleifera) is a tropical tree, sometimes called the “drumstick tree” or “miracle tree,” native to South Asia and now widely grown in Africa and the Middle East. The supplement is made from dried moringa leaves.
They are fundamentally different organisms. Their nutritional profiles reflect this — and their clinical evidence bases are similarly distinct.
Protein
Spirulina is 55–70% protein by dry weight with a PDCAAS of 0.87–0.98 — one of the highest among plant and algae sources. It provides all essential amino acids in reasonable proportions.
Moringa leaf powder is approximately 25–30% protein by dry weight with a PDCAAS of around 0.73–0.80 — lower than spirulina because moringa is lysine-limiting (common in legume and leafy green proteins). The protein quality is good for a plant leaf; it is not as complete as spirulina.
At a 5 g serving: spirulina provides approximately 3–3.5 g protein; moringa provides approximately 1.3–1.5 g. Spirulina wins clearly on protein quality and density.
Iron
Spirulina: approximately 6–10 mg iron per 10 g — one of the richest plant-source iron sources available. Non-haem, bioavailability enhanced by vitamin C.
Moringa: approximately 4–6 mg iron per 10 g — significant, but lower than spirulina. Also non-haem.
Spirulina wins on iron density, and has a stronger clinical evidence base for iron-deficiency correction.
Vitamin C
Moringa leaf powder: approximately 150–200 mg vitamin C per 100 g (1.5–2 mg per gram). At 5 g serving: approximately 7.5–10 mg — modest contribution but real.
Spirulina: negligible vitamin C (trace amounts only, largely destroyed in processing).
Moringa wins on vitamin C. This has a practical implication: the vitamin C in moringa may modestly enhance iron absorption when moringa and spirulina are combined in the same preparation.
Calcium
Moringa is a genuinely good calcium source: approximately 150–200 mg per 10 g — substantially more than spirulina (120–150 mg per 10 g). At 5 g: moringa provides 75–100 mg calcium; spirulina provides 36–75 mg.
Moringa wins on calcium. Relevant for people without dairy intake, as moringa is one of the better plant-source calcium providers.
Phycocyanin and unique bioactives
Spirulina’s phycocyanin is one of the most studied plant-derived anti-inflammatory compounds available. Its inhibition of NF-κB, COX-2, and 5-LOX, and its direct ROS scavenging activity, are well-characterised. No equivalent bioactive exists in moringa.
Moringa’s unique bioactives are isothiocyanates (particularly moringin), glucosinolates, and zeatin (a plant hormone). These have antioxidant and anti-inflammatory activity in vitro, and some animal model evidence. Their human clinical profile is less developed than phycocyanin.
Spirulina wins on evidence-backed unique bioactives.
Vitamin A (beta-carotene)
Moringa leaf is an excellent beta-carotene source: approximately 1.8–2.5 mg per gram — one of the best plant sources available. Important in populations where vitamin A deficiency exists.
Spirulina also provides significant beta-carotene: approximately 1.5–2 mg per gram — comparable to moringa.
Roughly equivalent on beta-carotene, with moringa slightly ahead on a per-gram basis in many analyses.
Clinical evidence base
Spirulina has approximately 50–70 published human randomised controlled trials across cholesterol, blood glucose, iron status, blood pressure, allergic rhinitis, and exercise performance.
Moringa has a growing clinical evidence base — 20–30 human trials of variable quality — particularly for blood glucose (type 2 diabetes populations), lipids, and anaemia. The evidence base is real but less extensive and generally less rigorous than spirulina.
Spirulina has the stronger and more consistent clinical evidence base.
Taste and palatability
Moringa has a mild, slightly bitter, earthy-green taste — described by most users as easier than spirulina. It dissolves reasonably well in water and blends.
Spirulina has the challenging oceanic/marine taste that requires a masking strategy (see how to make spirulina taste better).
Moringa wins on palatability — substantially easier for most people to integrate into food.
Combining spirulina and moringa
The profiles complement each other well for plant-based nutrition:
- Moringa’s vitamin C modestly enhances spirulina’s iron absorption when taken together
- Moringa adds calcium that spirulina does not provide well
- Spirulina adds phycocyanin, complete protein quality, and well-evidenced lipid/glucose benefits that moringa does not match
A 3 g spirulina + 3 g moringa combination in a smoothie provides both profiles with manageable taste (moringa softens spirulina’s marine edge).
Who should prioritise which
- Iron deficiency: Spirulina — better evidence, higher iron density
- Cholesterol/lipids: Spirulina — no equivalent evidence for moringa
- Vitamin C contribution: Moringa — spirulina has essentially none
- Calcium supplementation (vegan): Moringa — higher calcium per gram
- Anti-inflammatory (phycocyanin-specific): Spirulina — no equivalent in moringa
- Taste-sensitive users: Moringa — much easier to use daily
- Budget: Both are comparable at similar quality tiers; spirulina tends to be slightly cheaper per gram at equivalent quality