Spirulina | Supplementopedia

Overview

Spirulina (Arthrospira platensis and A. maxima) is a filamentous, photosynthetic cyanobacterium that thrives in alkaline, warm freshwater lakes. It is cultivated primarily as a protein‑rich dietary supplement, prized for its high content of phycocyanin, essential amino acids, and a spectrum of micronutrients that support overall human health.

Benefits

Antioxidant & anti‑inflammatory: Randomized trials show that spirulina’s phycocyanin and carotenoids reduce markers of oxidative stress (e.g., malondialdehyde) and inflammatory cytokines (IL‑6, TNF‑α).
Lipid metabolism: Meta‑analyses of 7–10 week trials report modest reductions in total cholesterol (‑5 %), LDL‑C (‑7 %), and triglycerides (‑8 %) without affecting HDL.
Blood‑pressure regulation: Small‑scale RCTs report systolic reductions of 3‑5 mm Hg in pre‑hypertensive adults, likely via nitric‑oxide‑mediated vasodilation.
Immune modulation: In vitro and human studies demonstrate enhanced NK‑cell activity and increased IgA secretion, suggesting improved host defense.
Exercise performance: Short‑term (4‑6 weeks) supplementation (2 g/day) improves time‑to‑exhaustion and reduces perceived exertion, attributed to improved mitochondrial efficiency.
Glycemic control: In type‑2 diabetic cohorts, 2 g/day for 12 weeks lowered fasting glucose (‑7 %) and HbA1c (‑0.5 %).

How It Works

Bioactivity: Spirulina's bioactivity stems from a dense matrix of phycocyanin, β‑carotene, γ‑linolenic acid, and a suite of B‑vitamins.
Phycocyanin Action: Phycocyanin acts as a potent scavenger of reactive oxygen species (ROS) by donating electrons to peroxyl radicals, thereby protecting cellular membranes. Its flavonoid‑like structures up‑regulate Nrf2, which drives transcription of antioxidant enzymes (SOD, catalase, HO‑1).
Protein and mTOR Signaling: The high‑quality protein supply provides essential amino acids that stimulate mTOR signaling, supporting muscle protein synthesis.
PPAR-α Modulation: ω‑3‑like γ‑linolenic acid and β‑carotene modulate the peroxisome proliferator‑activated receptor‑α (PPAR‑α) pathway, enhancing fatty-acid β‑oxidation and improving lipid profiles.
NF-κB Inhibition: Phycocyanin also inhibits NF‑κB activation, dampening pro‑inflammatory cytokine production.
Overall Effects: Together, these mechanisms improve oxidative balance, modulate metabolism, and support immune function.

Dosage

Typical Dosage: Clinical research typically uses 1–3 g per day of dried spirulina powder, taken with meals to improve absorption of fat‑soluble pigments.
Antioxidant/Lipid-Lowering: For antioxidant or lipid‑lowering effects, 2 g/day (divided into two doses) for 8–12 weeks is common.
Athletes: Athletes often use 2–5 g/day split pre‑ and post‑exercise to maximize mitochondrial benefits.
Special Populations: In pediatric or elderly populations, lower doses (0.5–1 g/day) are advisable.
Timing: Timing is flexible, but taking the first dose with breakfast and the second with lunch or dinner minimizes gastrointestinal upset.
Therapeutic Trials: For therapeutic trials (e.g., hypertension), 3 g/day for 12 weeks has shown consistent blood‑pressure reductions.
Titration: Always start with a lower dose (≈500 mg) for 1 week to assess tolerance, then titrate upward.

Safety & Side Effects

General Tolerance: Spirulina is generally well‑tolerated; mild gastrointestinal upset (bloating, mild diarrhea) occurs in <5 % of users.
Allergic Reactions: Rare allergic reactions (pruritus, rash) may occur in individuals with a history of cyanobacteria sensitivity.
Contraindications:
- Patients with phenylketonuria (due to phenylalanine content).
- Individuals with autoimmune disease on immunosuppressants (possible immune‑stimulating effects).
- Pregnant or lactating women—data are limited, so caution is advised.
Drug Interactions: Spirulina can potentiate anticoagulant drugs (warfarin, clopidogrel) due to its vitamin K content; monitor INR when co‑administered.
Contamination: Heavy‑metal contamination is the primary safety concern; only products certified free of microcystins, lead, and arsenic should be used.

Chemistry

Phycocyanin: Spirulina’s major bioactive pigment, phycocyanin, is a phycobiliprotein with the molecular formula C₁₁₈H₁₈₁N₁₁₈O₂₁₁S₁₆. Its IUPAC name is (α‑β)‑phycocyanin, a tetrameric protein composed of α‑ and β‑subunits each bound to a phycocyanobilin chromophore (C₅₅H₇₀N₈O₁₈).
Light Absorption: The pigment’s conjugated double‑bond system absorbs light at 620 nm, giving spirulina its characteristic blue‑green hue.
Other Key Compounds: Other key compounds include β‑carotene (C₄₀H₅₆, a polyene with 11 conjugated double bonds) and γ‑linolenic acid (C₁₈H₃₀O₂, a polyunsaturated fatty acid).
Composition: The overall dried biomass contains ~60 % protein (by weight), 7–10 % phycocyanin, 15 % carbohydrate (primarily polysaccharides), and 5–7 % lipids, of which 30 % are essential fatty acids.

Sources & Quality

Cultivation: Commercial spirulina is cultivated in controlled, alkaline ponds (pH 9–11) in regions such as China, the United States (Hawaii, California), India, and Mexico.
Harvesting and Drying: The algae are harvested by filtration, washed, and dried at ≤45 °C to preserve heat‑sensitive pigments. Freeze‑drying and spray‑drying are common industrial drying methods that preserve protein integrity and phycocyanin content.
Manufacturing Practices: Quality‑focused manufacturers employ closed‑system photobioreactors to minimize contamination by toxic cyanobacteria (e.g., Microcystis) and to control nutrient composition.
Product Certification: Certified organic and GMP‑certified products are preferred; third‑party testing for heavy metals, microcystins, and microbial load is essential for safety.
Wild Harvesting: Wild‑harvested spirulina is rare due to environmental variability and higher contamination risk.