The data obtained show that Spirulina contains unusually high levels of gamma-linolenic acid, an essential polyunsaturated fatty acid.

– J AOAC Int 2001 Nov-Dec;84(6):1708-14 — Fatty acid composition of Chlorella and Spirulina microalgae species. — Otles S, Pire R. — Ege University, Department of Food Engineering, Izmir, Turkey.

Samples of spirulina have also been found to be contaminated with animal hairs and insect fragments.

– Nakashima MJ, Angold S, Beavin BB, et al.– Extraction of light filth from spirulina powders and tablets: collaborative study. — J Assoc Off Anal Chem 1989;72:451–53.

May accumulate heavy metals from contaminated water, consuming blue-green algae from such areas can increase the body’s load of lead, mercury, and cadmium.
– Accumulation of mercury and other elements by spirulina (cyanophyceae). — Johnson PE and Shubert LE. — Nutr Rep Intl 1986;34(6):1063–71.