The nutrition facts of spirulina powder reveal a highly dense nutrient profile. One tablespoon (7 grams) of dried spirulina contains 20 calories, 4 grams of protein, 1.7 grams of carbohydrates, and 0.5 grams of fat. This single serving also provides significant amounts of B-vitamins, iron, copper, and the antioxidant pigment phycocyanin.
Spirulina (Arthrospira platensis) is a blue-green algae consumed globally as a dietary supplement. Its high nutrient density makes it one of the most efficient plant-based superfoods available. Unlike standard plant foods, spirulina has a soft cell wall without cellulose. This unique cellular structure allows the human digestive system to absorb 85 to 95 percent of its nutrients easily.
What Are the Macronutrients in Spirulina?
The macronutrients in 1 tablespoon (7 grams) of spirulina are 4.02 grams of protein, 1.67 grams of carbohydrates, and 0.54 grams of fat. Spirulina consists of 60 to 70 percent protein by dry weight, making it an exceptionally rich source of amino acids.
Macronutrients provide the structural foundation and energy required for bodily functions. The table below outlines the exact macronutrient breakdown for a standard 7-gram serving according to USDA data.
Spirulina Macronutrient Breakdown (Per 7g Serving)
Macronutrient | Amount per 7g | Percentage of Dry Weight | Daily Value (DV) |
|---|---|---|---|
Calories | 20.3 kcal | N/A | 1% |
Total Protein | 4.02 g | ~60% | 8% |
Total Carbohydrates | 1.67 g | ~24% | <1% |
Dietary Fibre | 0.25 g | ~3.6% | 1% |
Total Sugars | 0.22 g | ~3.1% | N/A |
Total Fat | 0.54 g | ~7.7% | <1% |
Protein Quality: The protein in spirulina is complete. It contains all 9 essential amino acids that the human body cannot produce.
Carbohydrate Type: The carbohydrates in spirulina are primarily complex polysaccharides. These complex structures absorb slowly and do not cause rapid blood sugar spikes.
Fat Profile: The small fat content contains valuable essential fatty acids, including gamma-linolenic acid (GLA), an omega-6 fatty acid known for its anti-inflammatory properties.
Learn the exact amount you should consume daily in our spirulina dosage guide.
What Vitamins Are in Spirulina?
Spirulina contains significant amounts of B-vitamins, including riboflavin (B2), thiamin (B1), and niacin (B3). A 7-gram serving delivers 20 percent of the daily value for riboflavin and 14 percent for thiamin. It also contains vitamin K, vitamin E, and beta-carotene (a precursor to vitamin A).
Vitamins in spirulina support cellular energy production, nervous system function, and antioxidant defence.
Spirulina Vitamin Profile (Per 7g Serving)
Vitamin | Amount per 7g | Percentage of Daily Value (% DV) | Health Benefit |
|---|---|---|---|
Riboflavin (B2) | 0.26 mg | 20% | Supports energy production and metabolism |
Thiamin (B1) | 0.17 mg | 14% | Converts carbohydrates into usable energy |
Niacin (B3) | 0.90 mg | 6% | Supports digestive health and nerve function |
Vitamin B6 | 0.03 mg | 2% | Aids amino acid metabolism |
Folate (B9) | 6.58 mcg | 2% | Supports DNA synthesis and cell division |
Vitamin K | 1.78 mcg | 2% | Supports blood clotting and bone health |
Vitamin E | 0.35 mg | 2% | Acts as a fat-soluble antioxidant |
Vitamin C | 0.71 mg | 1% | Minor immune support |
The Truth About Spirulina and Vitamin B12
Many older nutritional charts list spirulina as a massive source of vitamin B12. This is scientifically inaccurate. Spirulina contains pseudovitamin B12 (cobamide). This pseudo-form shares a similar chemical structure to true B12, but the human body cannot utilize it. Furthermore, pseudovitamin B12 can block the absorption receptors for real vitamin B12. Vegans and vegetarians must take a separate, true B12 supplement and should not rely on spirulina for their B12 needs.
Read the detailed clinical explanation in our spirulina vitamin B12 guide.
What Minerals Are in Spirulina?
Spirulina contains highly concentrated essential minerals, providing 2 milligrams of iron, 13.6 milligrams of magnesium, and 95 milligrams of potassium per tablespoon. The iron content is particularly notable because 7 grams supplies 11 percent of the daily recommended intake.
Spirulina absorbs minerals from its alkaline water environment during cultivation. These minerals support oxygen transport, muscle contraction, and electrolyte balance.
Spirulina Mineral Profile (Per 7g Serving)
Mineral | Amount per 7g | Percentage of Daily Value (% DV) | Health Benefit |
|---|---|---|---|
Copper | 0.43 mg | 47% | Supports iron absorption and red blood cell formation |
Iron | 2.00 mg | 11% | Crucial for haemoglobin production and oxygen transport |
Manganese | 0.13 mg | 6% | Supports bone formation and antioxidant enzyme function |
Magnesium | 13.6 mg | 3% | Regulates muscle function and nervous system signals |
Potassium | 95.2 mg | 2% | Maintains fluid balance and heart health |
Sodium | 73.4 mg | 3% | Maintains cellular fluid balance |
Phosphorus | 8.26 mg | 1% | Supports bone structure and ATP energy storage |
Calcium | 8.40 mg | 1% | Minor contribution to bone density |
Zinc | 0.14 mg | 1% | Minor immune system support |
Iron Bioavailability: The iron in spirulina is non-heme iron (plant-based). While non-heme iron usually has low absorption rates, the lack of cellulose in spirulina cell walls makes its iron highly bioavailable compared to spinach or legumes. Consuming spirulina with a vitamin C source (like lemon water) increases iron absorption by up to 67 percent.
Read more about maximizing this nutrient in our spirulina iron content guide.
What Is the Amino Acid Profile of Spirulina?
The amino acid profile of spirulina includes all 9 essential amino acids and 9 non-essential amino acids. A 7-gram serving contains substantial amounts of leucine (346 mg), valine (246 mg), and isoleucine (225 mg), which are the three branched-chain amino acids (BCAAs) vital for muscle repair.
Protein consists of long chains of amino acids. Because the human body cannot synthesize essential amino acids, they must come from food sources. Spirulina provides a complete amino acid profile, a rarity in the plant kingdom.
Essential Amino Acids (Per 7g Serving)
Amino Acid | Estimated Amount | Primary Function |
|---|---|---|
Leucine (BCAA) | 346 mg | Stimulates muscle protein synthesis |
Valine (BCAA) | 246 mg | Promotes muscle growth and tissue repair |
Isoleucine (BCAA) | 225 mg | Regulates blood sugar and energy levels |
Lysine | 212 mg | Supports calcium absorption and collagen production |
Threonine | 208 mg | Supports skin connective tissue |
Phenylalanine | 194 mg | Precursor to neurotransmitters (dopamine, adrenaline) |
Methionine | 80 mg | Supports tissue growth and zinc absorption |
Histidine | 76 mg | Precursor to histamine for immune response |
Tryptophan | 65 mg | Precursor to serotonin and melatonin (sleep regulation) |
Non-Essential Amino Acids (Per 7g Serving)
Amino Acid | Estimated Amount | Primary Function |
|---|---|---|
Glutamic Acid | 587 mg | Brain neurotransmitter function |
Aspartic Acid | 406 mg | Cellular energy cycle support |
Alanine | 316 mg | Energy metabolism in muscles |
Arginine | 290 mg | Nitric oxide production for blood flow |
Glycine | 217 mg | Component of collagen |
Serine | 210 mg | Central nervous system function |
Tyrosine | 181 mg | Thyroid hormone production |
Proline | 167 mg | Joint and tendon repair |
Cystine | 46 mg | Antioxidant defence component |
To learn how these amino acids build muscle and support recovery, read our spirulina protein content guide.
What Antioxidants Does Spirulina Contain?
Spirulina contains three powerful antioxidant compounds: phycocyanin, chlorophyll, and beta-carotene. Phycocyanin is the most abundant active compound, making up 10 to 15 percent of spirulina's dry weight.
Antioxidants neutralize reactive oxygen species (ROS) that cause cellular damage and aging.
Key Antioxidant Compounds
Compound | Concentration | Primary Benefit |
|---|---|---|
Phycocyanin | 10 to 15% | The unique blue pigment. It acts as a potent anti-inflammatory and inhibits oxidative damage to cells. |
Chlorophyll-a | ~1% | The green plant pigment. It binds to heavy metals in the gut and supports liver detoxification. |
Beta-carotene | ~0.1% | Precursor to vitamin A. It protects eye health and skin cell integrity. |
Phycocyanin sets spirulina apart from every other green superfood. This blue pigment is exclusively found in cyanobacteria and is currently the subject of extensive clinical research for its neuroprotective properties.
Read our complete breakdown of phycocyanin benefits.
How Does Spirulina Nutrition Compare to Other Superfoods?
Spirulina outperforms chlorella and wheatgrass in protein concentration and specific vitamin density. It contains 60 to 70 percent protein, whereas chlorella contains 50 to 60 percent, and wheatgrass contains 20 to 25 percent.
While all three are nutrient-dense green powders, their active compounds differ significantly.
Superfood Nutrition Comparison (Per 100g Dry Weight)
Nutrient | Spirulina | Chlorella | Wheatgrass |
|---|---|---|---|
Protein | 60 to 70 g | 50 to 60 g | 20 to 25 g |
Iron | 28.5 mg | 130 mg | 21.4 mg |
Vitamin A (as Beta-carotene) | High | High | Moderate |
Riboflavin (B2) | 3.67 mg | 4.3 mg | 2.0 mg |
Key Pigment | Phycocyanin (Blue-green) | Chlorophyll (Green) | Chlorophyll (Green) |
Cell Wall Digestibility | High (Soft wall) | Low (Requires cracking) | Moderate (Standard cellulose) |
Spirulina is the superior choice for users seeking maximum plant-based protein, iron bioavailability, and phycocyanin antioxidants. Chlorella provides more total iron but requires mechanical cell-wall cracking to make its nutrients bioavailable to humans.
Choose the right product for your needs using our best spirulina powder lab-tested rankings.
Frequently Asked Questions
How many calories are in one teaspoon of spirulina?
One teaspoon of dried spirulina powder contains approximately 7 calories. A standard teaspoon holds roughly 2.3 grams of powder. This small serving size provides 1.3 grams of protein and minimal carbohydrates, making it an excellent low-calorie nutrient booster for beverages and meals.
Does spirulina contain iodine?
Spirulina contains very low amounts of iodine compared to marine seaweeds like kelp or nori. Because spirulina grows in alkaline freshwater lakes or controlled freshwater ponds rather than the ocean, it does not accumulate high iodine levels. People with thyroid conditions who must avoid high iodine can generally consume freshwater spirulina safely, though they should always consult a doctor first.
Is the iron in spirulina easily absorbed?
Yes, the iron in spirulina absorbs more easily than iron from most other plant sources. While it is a non-heme iron, spirulina lacks the tough cellulose cell walls found in plants like spinach. This soft cellular structure allows stomach acids to access and dissolve the iron rapidly. Consuming spirulina with vitamin C maximizes this absorption process.
Does cooking destroy the nutrients in spirulina?
Yes, high heat destroys several heat-sensitive nutrients in spirulina. Cooking or boiling spirulina degrades its B-vitamins, vitamin C, and the antioxidant structure of phycocyanin. The protein and mineral content remains largely intact. To preserve the complete nutritional profile, mix spirulina into cold or room-temperature liquids, or add it to warm food just before eating. Do not boil it.
How much spirulina should I take daily for nutrition?
A standard nutritional dose is 1 tablespoon (7 grams) daily for adults. This amount delivers meaningful levels of protein, B-vitamins, and iron without causing digestive discomfort. Beginners should start with 1 teaspoon (2.3 grams) daily for the first week to allow the digestive system to adapt to the nutrient density before increasing the dose. Find the optimal timing in our best time to take spirulina guide.
Sources and Nutritional Data
USDA FoodData Central. Seaweed, spirulina, dried. [FDC ID: 170495]
Karkos PD, et al. (2011). Spirulina in clinical practice: evidence-based human applications. Evidence-Based Complementary and Alternative Medicine. [PMC3136577]
Gogna S, et al. (2022). Spirulina: an edible cyanobacterium with potential therapeutic benefits and toxicological consequences. Journal of Applied Phycology. [PubMed: 35916491]
Watanabe F, et al. (2014). Vitamin B12-containing plant food sources for vegetarians. Nutrients. [PMC4042564]
Grosshagauer S, et al. (2020). The true value of Spirulina. Journal of Agricultural and Food Chemistry.