There are multiple Spirulina species, and the best one depends on the intended use. Arthrospira platensis is widely used due to its high protein content (60–70%), β-carotene, and phycocyanin levels. It is also GRAS-approved by the FDA, which makes it easier to market and sell. When choosing Spirulina, opt for organic-certified, lab-tested products with high phycocyanin content (≥15%) for the best health benefits. Low-quality, mass-produced Spirulina may contain toxins, heavy metals, or reduced nutrient levels. Therefore, selecting products that come with a valid Certificate of Analysis (COA) is essential.