Which vitamin is found in spirulina?

November 26, 2025 •

4 min read

According to a study published in Chemical characterization and nutritional value of Spirulina, this blue-green algae contains high amounts of B-complex vitamins, including B2, B3, B5, and B9. This diverse nutritional profile explains why people want to know which vitamin is found in spirulina.

Quick Summary

Spirulina contains B vitamins (B1, B2, B3, B5, B6, B9), beta-carotene, and vitamin E, but its B12 is mostly an inactive analog not beneficial for humans.

Key Points

Diverse B-Complex: Spirulina provides a wide range of B vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), and B9 (folate).
Inactive B12 Analogs: A critical fact is that the B12-like substance found in spirulina is an inactive 'pseudo' vitamin B12, which is not reliably used by the human body.
Beta-Carotene Powerhouse: As a potent antioxidant, spirulina is rich in beta-carotene, which the body converts into active Vitamin A for immune health and vision.
Vitamin E and Antioxidants: It also supplies a good amount of Vitamin E, another fat-soluble vitamin with strong antioxidant properties that protect cells from damage.
Sourcing is Key for Safety: The purity and vitamin content can vary, so it is vital to source spirulina from reputable growers to avoid contamination with toxins or heavy metals.
Not a Vegan B12 Solution: Vegans should not rely on spirulina for their Vitamin B12 needs due to its high concentration of inactive B12 analogs and the risk it may interfere with absorption.

The B-Complex Vitamin Profile

Spirulina is a notable source of several B-complex vitamins, which are crucial for energy metabolism and overall cellular function. This makes it a popular dietary supplement for those seeking to boost their intake of these important nutrients. The B vitamins found in spirulina include:

Thiamine (Vitamin B1): Essential for converting carbohydrates into energy and supporting nerve function.
Riboflavin (Vitamin B2): Plays a key role in energy production, cellular growth, and the metabolism of fats, drugs, and steroids.
Niacin (Vitamin B3): Critical for cellular metabolism and supporting the nervous and digestive systems.
Pantothenic Acid (Vitamin B5): Necessary for producing energy and creating hormones and cholesterol.
Pyridoxine (Vitamin B6): Important for brain development, immune function, and red blood cell formation.
Folate (Vitamin B9): Crucial for DNA synthesis and repair, making it vital for cell growth and tissue formation.

The B12 Controversy: Spirulina's Biggest Misconception

One of the most persistent myths surrounding spirulina is that it is a reliable source of Vitamin B12, a nutrient primarily found in animal products. The truth is more nuanced. While spirulina contains a B12-like compound, it is mostly an inactive form known as pseudo-B12 or cobamide. This pseudo-B12 is not bioavailable to humans and cannot fulfill the body's B12 requirements. Worse, some studies suggest it may interfere with the absorption of the active B12 form. Therefore, vegans and vegetarians should not rely on spirulina for this crucial nutrient and should seek out fortified foods or supplements containing active Vitamin B12. High-quality spirulina is often grown in controlled environments, but it is not a solution for B12 deficiency.

Beyond B-Vitamins: Fat-Soluble Vitamins in Spirulina

In addition to the water-soluble B-complex, spirulina also provides a significant dose of fat-soluble vitamins, further solidifying its reputation as a nutrient-dense food.

Beta-Carotene (Provitamin A): Spirulina is an exceptional source of beta-carotene, a plant pigment that the body efficiently converts into Vitamin A. This potent antioxidant is vital for maintaining healthy vision, robust immune function, and cell growth.
Vitamin E (α-tocopherol): This powerful antioxidant is present in spirulina and works to protect the body's cells from oxidative damage caused by free radicals. This protection is important for overall cellular health.
Vitamin K: While in smaller quantities, spirulina also contains Vitamin K, which is essential for blood clotting and bone health.

Sourcing Matters: Avoiding Contamination

The nutrient content of spirulina can vary significantly based on its growing conditions. To ensure a product is both nutrient-rich and safe, it is crucial to source it from reputable growers. Poorly grown spirulina, especially that harvested from polluted waters, can be contaminated with microcystins (harmful toxins) or heavy metals like lead and mercury. Controlled farming environments produce a purer, higher-quality product, but consumers must remain diligent and choose brands that provide third-party lab testing results to verify purity. The risk of contamination is a significant factor to consider alongside its nutritional benefits.

Spirulina vs. Chlorella: A Quick Vitamin Comparison

When considering microalgae supplements, a comparison between spirulina and its cousin, chlorella, is often useful. While both are considered superfoods, their nutritional profiles and benefits have key differences, particularly concerning vitamins.


Feature	Spirulina	Chlorella
Vitamin B12	Contains inactive pseudo-B12, not a reliable source for humans.	Contains some genuine, active Vitamin B12, but levels can vary depending on growing conditions.
B-Vitamins	Excellent source of B1, B2, B3, B5, B9.	Good source, but generally less comprehensive than spirulina.
Vitamin A	Extremely rich source of beta-carotene.	Also a rich source, though some reports indicate it is higher in spirulina.
Vitamin E	Good source of the antioxidant α-tocopherol.	Good source, with content levels often comparable to spirulina.
Digestion	Cell walls are easily digested, allowing for high nutrient bioavailability.	Has a tough, indigestible cell wall that must be mechanically broken for nutrient absorption.

Conclusion: More Than Just a Vitamin Source

So, which vitamin is found in spirulina? The answer is a wide array, including several vital B-complex vitamins (B1, B2, B3, B5, B6, B9), beta-carotene (provitamin A), and Vitamin E. While it offers a impressive spectrum of nutrients, it is crucial to remember the distinction regarding its Vitamin B12 content. The pseudo-B12 found in spirulina is not a viable dietary source for humans, a fact of particular importance for vegans and vegetarians. By understanding both the robust vitamin profile and the key limitations, consumers can make informed choices about incorporating this superfood into their diet while prioritizing quality and safety.

For a deeper scientific dive into spirulina's composition and bioactivities, you can consult research documented on the National Institutes of Health website.

Frequently Asked Questions

No, spirulina contains mostly inactive pseudo-B12 that is not reliably used by the human body and should not be considered a substitute for a genuine B12 supplement, especially for vegans.

To ensure safety, purchase spirulina from reputable brands that test their products for toxins and heavy metals. Look for third-party certifications and information about the product's sourcing.

Yes, spirulina contains some amount of Vitamin C (ascorbic acid), though the content is not as high as other sources like citrus fruits.

While both are nutrient-dense algae, spirulina provides a wider range of B-vitamins and more beta-carotene, while chlorella contains some amount of active B12, unlike spirulina's inactive version.

Beta-carotene is a plant pigment that the body converts into active Vitamin A. It is a powerful antioxidant found abundantly in spirulina and is important for immune function, vision, and skin health.

While generally safe, excessive intake of spirulina could potentially lead to side effects. The vitamins themselves are unlikely to cause issues at normal dosages, but high levels of other compounds can cause digestive upset.

Phycocyanin is the blue pigment protein in spirulina, acting as a potent antioxidant and anti-inflammatory agent. While not a vitamin, it contributes significantly to spirulina's overall health benefits.