Always choose a Chlorella supplement that comes from a reputable company that sells quality products. Chlorella grown in contaminated waters retains high levels of toxins and can cause dangerous side effects. Pure and organic Chlorella grown in clean and well tested waters is generally safe and free from harmful side effects.

Even pure organic Chlorella may cause a few side effects. These side effects are mild and usually diminish as the body becomes adjusted to the supplement. Side effects include diarrhea, nausea, gas (flatulence), green discoloration of the stool, and stomach cramping.

One of the great benefits of Chlorella is that it boosts the immune system, but people with conditions such as multiple sclerosis, rheumatoid arthritis, or lupus should not take this supplement. These conditions are auto-immune diseases. Chlorella stimulates the immune system and could worsen the condition.

With any drug or supplement, it is best to consult a physician, especially if pregnant or breast-feeding. Even though our lab testing results show mercury levels are non-detectable, Chlorella can have a high content of mercury, and it is not advised for women who pregnant or breast-feeding women.

In extremely rare cases, consumers have reported an allergic reaction to Chlorella. The symptoms included breathing problems, chest tightness, hives, itching and/or a rash. These symptoms are considered major side effects. If you experience these symptoms, consult a physician immediately.

If you are currently taking blood thinners, namely Coumadin, or its generic Warfarin, you should not take Chlorella. Chlorella may have high levels of Vitamin K which when combined with a blood thinner could affect blood clotting.