Phycocyanin (Blue Spirulina): Nutrients, What Research Shows and Safety

Phycocyanin is a blue pigment-protein made by spirulina (Arthrospira platensis), a blue-green alga. Companies filter it out of the alga with water to make "spirulina extract" or "blue spirulina", used to color drinks, candy, frosting and lattes, and also sold as powders and capsules. [1] This page keeps the food color apart from the supplement and from lab findings. It is separate from whole spirulina, which has its own page: spirulina.

Read this first

• As a food color it is regulated. In the U.S., the FDA rule for "spirulina extract" (21 CFR 73.530) lists many foods it may color, and sets limits for lead, arsenic (each no more than 2 mg/kg), mercury (no more than 1 mg/kg), and requires a negative test for microcystin toxin. [1]
• Human evidence for health benefits is small. In the sources we read, we found no randomized human trial of purified phycocyanin. Most findings are in cells and animals. [3] [4] [8]
• Allergy: phycocyanin was identified as a sensitizing allergen in a related blue-green alga in patient blood tests, and anaphylaxis is listed as an adverse effect of blue-green algae supplements. For trouble breathing or swelling of the face or throat, call 911 (or your local emergency number). [5] [6]
• Supplements are not the same as the food color. The color rule has a microcystin test; supplements are not regulated in the same way, and contamination has been found in blue-green algae products. [1] [6] [7]
• Color fades: heat, light, oxygen and acidity can destroy the blue. [2] [9]

What is in it (USDA values)

No USDA entry for this food. USDA FoodData Central (SR Legacy) has no record for phycocyanin or spirulina extract. The FDA describes the color additive as an aqueous extract of dried Arthrospira platensis biomass whose main coloring parts are phycocyanins. [1] We did not find a nutrient table for the extract in the sources we read. As a color, only small amounts are used ("good manufacturing practice" is the legal limit), so it adds little nutrition to a drink or candy. [1]

Plant compounds: phycocyanin and its relative allophycocyanin showed antioxidant and anti-inflammatory activity in a 2026 cell study (nerve and immune-type cells in dishes). [4] That is laboratory evidence only.

What research says

Food versus supplement. The blue color in foods is a small amount of extract. The trials above used whole spirulina or lab-grade pigment, not blue latte powder. A systematic review calls for clinical validation of phycobiliproteins. [2]

How much is a normal serving

There is no official serving size for phycocyanin. The FDA sets no number for the color, only "good manufacturing practice" levels. [1] This is information, not a prescription. For supplements, ask a clinician or pharmacist.

Safety, allergy and medicines

• Allergy: in blood samples from people with allergic rhinitis, phycocyanin and a linker peptide from Microcystis aeruginosa were the main sensitizing proteins. [5] MSK lists anaphylaxis among reported effects of blue-green algae supplements. [6] An EFSA opinion on a similar extract (blue galdieria) judged allergenicity risk low, using spirulina data, but that is a different product. [12]
• Toxin contamination: the FDA color rule requires microcystin-negative extract. [1] Supplements made from blue-green algae have had microcystin contamination, mostly AFA from Klamath Lake: see AFA. [7] Ask for a lab report.
• Medicines: MSK says spirulina inhibits two liver enzymes (CYP1A2 and CYP2E1), with unknown clinical meaning. This is spirulina, not purified phycocyanin. [6]
• Pregnancy and breastfeeding: Proper evidence not found in the sources we read for phycocyanin.
• PKU: Proper evidence not found in the sources we read.
• Autoimmune disease: Proper evidence not found in the sources we read. Ask a specialist.
• Regulatory note: the page we read says an amendment to this rule (91 FR 5295, Feb 2026) was delayed indefinitely. [1] Check the current rule.

Choosing, storing and food safety

• Heating, light and acid reduce the blue. A 2026 study of phycocyanin-rich powder found drying at 70 degrees C preserved phycocyanin best; hotter drying broke it down more. [9]
• Sensitivity to heat, light, oxygen and pH limits food use of phycobiliprotein pigments, and encapsulation can improve stability. [2] [13]
• A blue color on a label (for example "spirulina extract") shows the ingredient; it is not a health claim.

Related pages

• Spirulina
• AFA (blue-green algae)
• Blue-green algae supplements: microcystins and quality
• Spirulina vs chlorella
• Food allergy basics and emergency signs