What phycocyanin is and why it matters
C-phycocyanin is the blue-chromoprotein that gives spirulina its distinctive colour. It is not merely a pigment — phycocyanin is pharmacologically active:
- Directly inhibits COX-2 (anti-inflammatory)
- Inhibits NF-κB (anti-inflammatory, anti-tumour)
- Scavenges peroxyl radicals (antioxidant)
- Inhibits NADPH oxidase via phycocyanobilin chromophore
- Has anti-cancer activity in vitro and animal models
Most of spirulina’s health benefits beyond protein and iron supplementation are mediated by phycocyanin — making its concentration the most important quality metric beyond contamination testing.
Phycocyanin content in commercial spirulina
Phycocyanin content (measured as % of dry weight by spectrophotometry at A615/A652) varies substantially:
| Spirulina type | Typical phycocyanin content | Per 5 g serving |
|---|---|---|
| Low-quality commodity (spray-dried, high temperature) | 3–8% | 150–400 mg |
| Standard quality (spray-dried) | 8–15% | 400–750 mg |
| Premium quality (low-temp spray or freeze-dried) | 15–25% | 750–1,250 mg |
| Phycocyanin extract (isolated powder) | 60–80% | 3,000–4,000 mg (5 g serving of extract) |
Visual indicator: a blue-green, vibrantly coloured spirulina retains high phycocyanin; olive-green or brownish spirulina has had phycocyanin heat-degraded during processing.
What clinical trials actually use
Human trials demonstrating anti-inflammatory, antioxidant, and metabolic effects use isolated phycocyanin or high-phycocyanin spirulina at specific doses:
- Anti-inflammatory trials: 100–500 mg/day isolated phycocyanin — equivalent to 0.7–3.3 g high-quality spirulina or 1.3–6.7 g standard spirulina
- Cholesterol and metabolic trials: 1–8 g/day whole spirulina — providing 80–1,200 mg phycocyanin depending on quality
- Anti-cancer cell studies: 25–100 µg/mL in vitro — not directly comparable to oral dosing
The effective phycocyanin dose for documented clinical effects appears to start at approximately 200–400 mg/day, achievable from 3–5 g standard-quality spirulina.
How to calculate your phycocyanin dose
Most spirulina products do not disclose phycocyanin content on the label. To estimate:
- Check the Certificate of Analysis (CoA) — some CoAs include phycocyanin content. This is the only reliable number.
- Use colour as a proxy: bright blue-green spirulina from a reputable supplier with freeze-drying or low-temperature processing is likely 15%+ phycocyanin. Standard spray-dried commodity is likely 8–12%.
- At 10% phycocyanin (a conservative middle estimate): 5 g spirulina provides 500 mg phycocyanin. At 3 g/day: 300 mg/day.
300–750 mg/day phycocyanin from 3–5 g quality spirulina is a reasonable estimate for the middle range of commercially available products.
Phycocyanin extract vs whole spirulina
Pure phycocyanin extract products (sold as blue powder, often used as natural food colouring or as a supplement) provide phycocyanin in isolation without the protein, iron, GLA, and beta-carotene that whole spirulina provides.
For the specific phycocyanin anti-inflammatory mechanism: extract is more dose-efficient — 1 g extract provides the phycocyanin of 6–8 g whole spirulina powder.
For comprehensive nutritional value (protein, iron, B vitamins): whole spirulina is preferred — the phycocyanin is a bonus within a complete nutritional package.
For people specifically targeting phycocyanin effects (inflammation, antioxidant) without the caloric or taste impact of high-dose whole spirulina: phycocyanin extract at 500 mg–1 g/day is an efficient approach.
Stability: phycocyanin degradation over time
Phycocyanin degrades through two mechanisms:
- Heat: Denatures above 60°C; all baking or cooking destroys it
- Light and oxidation: UV light and oxygen degrade phycocyanin in powder or dissolved form; store in airtight, opaque containers away from direct light
- Acidic pH: Phycocyanin precipitates below pH 4 — citrus juice dissolves spirulina but the acid can degrade phycocyanin over time; prepare just before consumption, not in advance
Taking spirulina immediately after dissolving in liquid (rather than preparing hours in advance) maximises the phycocyanin delivered. Tablets are typically more stable than pre-dissolved liquid for phycocyanin preservation.
Maximising phycocyanin from your spirulina
- Choose spirulina that discloses phycocyanin content in the CoA — or from suppliers who document low-temperature processing
- Avoid cooking or baking with spirulina if phycocyanin is the goal
- Mix powder just before consumption; don’t pre-dissolve in acidic liquid hours in advance
- Store in a sealed, opaque container at room temperature away from light and heat