A single tablespoon (7 grams) of dried spirulina powder contains:
Protein: 4 grams
Vitamin B1 (thiamine): 11% of the RDA
Vitamin B2 (riboflavin): 15% of the RDA
Vitamin B3 (niacin): 4% of the RDA
Copper: 21% of the RDA
Iron: 11% of the RDA
It also contains decent amounts of magnesium, potassium and manganese