Spirulina: Calories, Nutrition and Health Benefits

The blue-green algae superfood with 60% protein per 100g—but only 2g per realistic 3g serving. Learn the truth about heavy metals, protein claims, and actual health benefits.

Quick Nutrition Facts

Per 1 Teaspoon Spirulina Powder (3g)

Nutrient	Amount
Calories	9 kcal
Protein	2g
Carbohydrates	0.7g
Fiber	0.1g
Sugars	0g
Fat	0.24g
Iron	0.84mg
Thiamin (B1)	0.07mg
Riboflavin (B2)	0.11mg
Niacin (B3)	0.4mg

Per 100g (reference only): 290 kcal, 57g protein, 24g carbs, 8g fat

Macronutrient Breakdown

NUTRITIONIST INSIGHT

Spirulina is 60% protein by weight but typical 3g serving provides only 2g protein—useful for vitamins (B1, B2, B3) and iron (28% DV), not as primary protein source. Quality matters: choose certified brands tested for heavy metals.

Myth Busters

MYTH #1: Spirulina Is a Great Protein Source

TRUTH: While 60% protein per 100g sounds impressive, typical serving is 3g providing only 2g protein. To get 30g protein, you'd need 50g spirulina costing $5-10 per serving—impractical compared to eggs (6g protein per egg, $0.25).

MYTH #2: All Spirulina Contains Dangerous Heavy Metals

TRUTH: Studies testing commercial spirulina found lead, mercury, and cadmium below FDA safety limits in quality products. Chinese supplements had higher contamination; choose NSF/USP certified brands from Hawaii, California, or controlled facilities.

MYTH #3: Spirulina Is a Complete Protein Equivalent to Meat

TRUTH: Spirulina contains all essential amino acids but is relatively low in cysteine. More importantly, bioavailability and digestibility are lower than animal proteins. Use as supplement, not protein replacement.

MYTH #4: You Need 10-20g Spirulina Daily for Benefits

TRUTH: Most studies show benefits at 3-6g daily. Higher doses don't necessarily provide more benefits and can cause digestive issues (nausea, diarrhea). Start with 1g and gradually increase to 3-6g max.

MYTH #5: Spirulina Causes Liver Damage

TRUTH: Spirulina itself doesn't cause liver damage. However, contaminated products or confusion with toxic blue-green algae (microcystins) can harm liver. Quality spirulina is safe and may even protect liver.

MYTH #6: Spirulina Detoxifies Heavy Metals from Your Body

TRUTH: Limited evidence. While spirulina may bind some metals in test tubes, human detox claims lack strong scientific support. Ironically, contaminated spirulina can introduce heavy metals rather than remove them.

NutriScore by Health Goals

Health Goal	NutriScore	Why This Score?
Weight Loss		Only 9 calories per serving but minimal satiety. Expensive for limited impact. Better vitamin/mineral support than weight loss tool.
Muscle Gain		Only 2g protein per 3g serving—impractical as protein source. Would need 45g spirulina for 30g protein (expensive, digestive issues). Use whey, chicken, eggs instead.
Diabetes Management		Low GI, minimal carbs (0.7g per serving). Some studies show improved glucose control but effects modest. Safe addition, not primary intervention.
PCOS Management		Antioxidants (phycocyanin) may reduce inflammation. B vitamins support hormone metabolism. Limited direct PCOS research but safe to include.
Pregnancy Nutrition		Rich in iron (28% DV per 3g), folate, B vitamins essential for pregnancy. However, choose certified brands to avoid heavy metal risk. Consult doctor before use.
Immune Support		Studies show increased antibody production and reduced inflammation markers. Rich in antioxidants, B vitamins support immune function.

PERSONALIZED NUTRITION

Track your meals with NutriScan for personalized NutriScores based on your specific health goals!

Blood Sugar Response to Spirulina

Spirulina has minimal impact on blood sugar due to negligible carbohydrate content per serving.

Typical Glucose Response Curve

*This chart shows minimal blood glucose impact from typical 3g spirulina serving. Individual responses may vary. Not medical advice.*

Best Ways to Consume Spirulina

Spirulina has a strong seaweed/ocean taste. Here's how to mask it:

🍌 Fruit smoothies - Blend with banana, mango, pineapple (fruit sweetness masks taste)
🥤 Green juices - Mix with apple, cucumber, celery, lemon
🥛 Yogurt or oatmeal - Stir into Greek yogurt or overnight oats
💊 Tablets/capsules - Avoid taste entirely (more expensive but convenient)

Pro tip: Start with ½ teaspoon (1g) to assess tolerance before increasing to full 3g dose.

Cultural Significance

Spirulina has been consumed by humans for centuries, though modern commercialization began in the 1970s.

Historical Use:

Aztecs harvested spirulina from Lake Texcoco (Mexico) as "tecuitlatl"
African Kanembu people in Chad harvest spirulina from Lake Kossorom as "dihé"
Traditional food source for both cultures for hundreds of years
NASA researched spirulina for space missions in the 1980s due to nutrient density

Modern Industry:

Commercial production began in 1970s
Major producers: Hawaii, California, Thailand, China, India
Global market valued at $400+ million (2020)
Marketed as "superfood" despite mixed scientific evidence

In India:

Growing interest in Ayurvedic and wellness communities
Local production in Tamil Nadu, Gujarat
Marketed for protein, immunity, energy, and anemia
Often promoted with exaggerated detox and weight loss claims

Compare & Substitute

Spirulina vs Similar Supplements (Per 3g Serving)

Nutrient	💚 Spirulina	💚 Chlorella	🐟 Fish Oil (1 cap)	🥚 Egg White Powder (10g)
Calories	9 kcal	8 kcal	10 kcal	40 kcal
Protein	2g	1.8g	0g	8g
Carbs	0.7g	0.6g	0g	0g
Fat	0.24g	0.3g	1g (EPA/DHA)	0g
Iron	0.84mg (5% DV)	1mg (6% DV)	0mg	0mg
B Vitamins	High (B1, B2, B3)	Moderate	None	Low
Omega-3	Trace	Trace	300mg EPA/DHA	None
Best For	Vitamins, iron, antioxidants	Detox claims, chlorophyll	Heart health, inflammation	Protein supplementation

Frequently Asked Questions

Is spirulina safe from heavy metals?

Yes, quality spirulina is safe. Studies testing 25 commercial products found lead, mercury, cadmium below FDA safety limits in reputable brands.

How to choose safe spirulina:

Look for NSF International or USP certification
Choose brands with third-party testing (published COAs)
Prefer Hawaiian, Californian, or controlled-facility sources
Avoid cheap Chinese imports
Check for organic certification

Maximum measured values: Cadmium 226 μg/kg, Lead 1320 μg/kg—both below maximum allowed limits.

Does spirulina really have 60% protein?

Yes, dried spirulina is 60-70% protein per 100g. However, this is misleading for practical use.

Reality check:

Typical serving: 3g spirulina = 2g protein
To get 30g protein: need 50g spirulina (cost: $5-10)
Better protein sources: chicken breast (31g per 100g, $0.50), whey protein (24g per scoop, $0.75)

Examine.com confirms spirulina is complete protein but only dosed up to 10g daily, providing 7.5g protein at best—"helps reach protein goals but fulfills only a fraction of daily requirements."

How much spirulina should I take daily?

Recommended dosing:

Beginners: 1g (⅓ tsp) daily for 1 week to assess tolerance
Standard dose: 3-6g (1-2 tsp) daily for health benefits
Maximum: 10g daily (experienced users only)

Most studies showing benefits use 3-6g daily. Higher doses don't necessarily provide more benefits and can cause nausea, diarrhea, or stomach discomfort.

Is spirulina good for weight loss?

Limited evidence. Small serving (3g = 9 calories) won't hurt weight loss, but claims about appetite suppression and fat burning lack strong scientific support.

What research shows:

Some studies report modest appetite reduction
No significant fat loss compared to placebo
Effects likely due to nutrient density, not fat burning

Better used for vitamin/mineral support than primary weight loss tool. Don't expect miracles.

Can spirulina boost immunity?

Some evidence supports immune benefits. Studies show spirulina may increase antibody production and reduce inflammatory markers (TNF-α, IL-6).

Immune benefits:

Rich in antioxidants (phycocyanin) that fight oxidative stress
B vitamins (thiamin, riboflavin, niacin) support immune cell function
May enhance natural killer cell activity
Anti-inflammatory properties reduce chronic inflammation

However, effects are modest. Not a replacement for balanced diet, sleep, and stress management.

Does spirulina taste bad?

Yes, spirulina has a strong seaweed/ocean/fishy taste that many find unpleasant. It's often described as "swampy" or "pond-like."

How to mask the taste:

Smoothies: Blend with banana, mango, berries, pineapple
Juice: Mix into apple, orange, or green vegetable juice
Yogurt: Stir into Greek yogurt with honey
Tablets/capsules: Completely avoid taste (more expensive)

Starting with small amounts (½ tsp) helps you gradually adapt. Some people never get used to it and prefer capsules.

Can I take spirulina every day?

Yes, daily spirulina is safe for most people at 3-6g doses. Long-term studies show no adverse effects with quality products.

When to avoid:

Autoimmune conditions (lupus, MS, RA): May overstimulate immune system
Phenylketonuria (PKU): Spirulina contains phenylalanine
Pregnancy/breastfeeding: Consult doctor first (heavy metal risk)
Blood thinners: Spirulina has mild anticoagulant effects

Always choose certified, tested brands to minimize contamination risk.

Similar Nutritious Superfoods

Acai BowlsAshwagandhaBananaBone BrothChia SeedsChlorellaEggsGolden MilkKefirKimchiKombuchaMatchaMoringaNutritional YeastQuinoaSea MossSpirulina

Spirulina: Calories, Nutrition and Health Benefits ​

Quick Nutrition Facts ​

Macronutrient Breakdown ​

Myth Busters ​

NutriScore by Health Goals ​

Blood Sugar Response to Spirulina ​

Typical Glucose Response Curve ​

Best Ways to Consume Spirulina ​

Cultural Significance ​

Compare & Substitute ​

Frequently Asked Questions ​

Is spirulina safe from heavy metals? ​

Does spirulina really have 60% protein? ​

How much spirulina should I take daily? ​

Is spirulina good for weight loss? ​

Can spirulina boost immunity? ​

Does spirulina taste bad? ​

Can I take spirulina every day? ​

Similar Nutritious Superfoods ​

Explore More Nutrition Tools & Resources ​