Spirulina is a blue-green algae that grows in both fresh and salt water. You can find it as a powder or tablet. People take it for energy and immune function. Others take it to help keep cholesterol levels in a normal range. This algae supplies protein, vitamins, and minerals.
Most people take spirulina once a day with food.
Those with phenylketonuria (PKU) must avoid spirulina. Anyone with an autoimmune condition or who is pregnant should talk to a doctor before using it.