I have been taking Spirulina regularly (tablet and powder) for 35 years. I am in my mid-seventies now and have NO health issues. I do take whole food supplements, but NO prescriptions (I don't need any). Spirulina healed me of chronic (life-long) intestinal problems - including diverticulosis - 24/7 allergies, fatigue, and more. But you do need to be very careful who you purchase the Spirulina from. I make sure I purchase high grade Organic. I really can't live without Spirulina. There are impurities that can make its way into the Spirulina which could cause health issues, but Spirulina itself is an extraordinary green-food.
I have never gotten heartburn or acid reflux, but right after Christmas after eating some powerful homemade pasta sauce and too much tea and coffee the next morning I got up I had so much pain I was doubled over for hours. It was severe burning pain that was halfway between my naval and my breasts. I figured it was acid, so I decided to take something high in alkaline so after 5 hours of pain, I took a shot of Chlorella and Spirulina powder in a shot glass with water. Within about 30 seconds the pain was GONE! I have NEVER gotten such instant relief before.
I try to take a shot of this daily but had stopped doing it over the holidays as it got pushed back in the refrig.
I buy pacifica spirulina in powdered form since it is the purest form and the large jug of jarrow chlorella. This is the most cost effective way for me to take it. My husband will never take it this way so I purchased empty capsules and a capsule filler tool so he can have the purest form as well. I don't understand why they don't sell capsules without adding all the fillers.
One other thing about the chlorella & spirulina; for those of you suffering from acne; it's the best thing you can take for it. Start out slow as you will detox first and may get headaches & other symptoms. I started with 1/2 tsp. Of the combination for 1-2 weeks then moved up to 1 tsp and now I take about 2 teaspoons and give the last 1/4 cup to my dog. Dogs LOVE green powder, but it's messy dry so I just give her the rest of mine that I have mixed in water. It doesn't taste good at all, I have forced myself to take it anyway since I hate taking pills and this is the absolute purest form. A couple seconds to chug it and follow with a healthy oily food like a salad with flax oil or olive oil is perfect as the oil helps your body absorb it. Some people put the green powder on their salad; thats a matter of taste.