You've probably heard people talking about spirulina, chlorella, and blue spirulina, since they're superfoods that have taken over social media and every health-focused restaurant — especially blue spirulina and its magical blue color, which turns any drink into a work of art.

But these ingredients aren't actually new. Spirulina belongs to a lineage — cyanobacteria — that has existed on Earth for about 3.5 billion years, making it one of the first photosynthetic organisms on the planet. Other sources place its origin within a somewhat wider range, but to put it in context, Earth itself is about 4,500 million years old, so that lineage has been around since practically the earliest chapters of life on the planet — long before plants, animals, or any form of complex life existed.

So since when have we been eating it? Well, it's documented that the Aztecs harvested it and dried it in the sun to include in their diet, since they considered it a nutrient-rich food. After the Spanish conquest, its consumption declined and was almost lost.

Chlorella, on the other hand, belongs to the lineage of green algae, whose origin dates back roughly a billion years according to the fossil record, also making it one of the oldest life forms on the planet. It was discovered by a Dutch microbiologist and botanist named Martinus Willem Beijerinck, who first identified and described it in 1890.

So as you can see, all these "trendy" ingredients aren't as new as you might think. But let's dig a little deeper into each one.

Are they algae?

Here's an important scientific nuance worth clarifying from the start, because even a lot of brands and health articles get this wrong: of the three, only one is actually a true alga.

Spirulina (Arthrospira platensis) is NOT an alga; it's a microscopic photosynthetic cyanobacterium. In other words, it's a type of microorganism capable of using sunlight to produce energy through photosynthesis, just like plants do. Although each of its cells can live and function on its own, these cells usually grow attached to one another, forming long chains or filaments in a spiral shape.

Think of it this way: imagine countless tiny cells holding hands, forming a sort of spiral thread. Each one is an independent cell, but together they form what we know as spirulina.

Although it's commonly called "blue-green algae," that's a popular name, not an accurate scientific classification.

Chlorella (Chlorella vulgaris or Chlorella pyrenoidosa) IS a true alga. It's a eukaryotic organism (with a defined cell nucleus), unicellular — each organism is a single, independent spherical cell — and belongs to the same evolutionary lineage that land plants descend from.

So-called "blue spirulina" isn't a different species or a third type of organism: it's a concentrated extract obtained from spirulina itself, centered on its blue pigment, phycocyanin. Why are people so fascinated by this ingredient? Not just for its nutritional benefits, but also for its incredible color and neutral taste.

1. SPIRULINA

As we mentioned, the Aztecs consumed spirulina harvested from Lake Texcoco in Mexico, turning it into a kind of dried cake called tecuitlatl. In Africa, communities in the Lake Chad region have also traditionally harvested it to prepare a food known as dihé.

What does it give us?

Dried spirulina can contain approximately 50–70% protein, depending on the species and how it was grown and processed. It contains all the essential amino acids and also provides iron, carotenoids like beta-carotene and zeaxanthin, chlorophyll, vitamins, and minerals.

It also contains gamma-linolenic acid (GLA), an omega-6 fatty acid that's relatively uncommon in food.

But probably one of its most fascinating components is phycocyanin, the blue pigment responsible — along with chlorophyll — for its characteristic blue-green color.

Phycocyanin doesn't just add color. It's a bioactive compound with antioxidant and anti-inflammatory properties that's currently being widely studied.

An important detail: although spirulina contains compounds related to vitamin B12, much of it corresponds to analogs that our body can't use as true vitamin B12. Because of this, it shouldn't be considered a reliable source of B12 or used as a substitute for a supplement when there's a deficiency.

What are its benefits?

Cardiovascular health. Spirulina supplementation can produce modest reductions in total cholesterol, LDL, and triglycerides, along with small increases in HDL. Reductions in blood pressure have also been observed, especially in people who already have elevated levels.

Glucose and metabolism. Some studies show improvements in fasting glucose, insulin, and insulin resistance.

Inflammation and oxidative stress. Phycocyanin, carotenoids, and other compounds in spirulina have significant antioxidant activity in experimental studies. In humans, some trials and meta-analyses have also found improvements in certain inflammatory and oxidative stress markers, although results aren't consistent across all studies.

Body weight. Some meta-analyses have found small reductions in weight and BMI, especially in people who are overweight or obese. That said, we're talking about a complementary and relatively small effect — spirulina isn't a weight-loss supplement on its own.

Immune system. There's research suggesting that spirulina and its bioactive compounds may modulate different components of the immune response. However, much of this research is still experimental or comes from small human studies, so it's more accurate to talk about a possible immunomodulatory effect than to simply claim it "boosts your immune system."

How to take it

Clinical trials have used very different amounts, generally around 1–8 g daily, depending on the outcome being studied.

For everyday use, 2–3 g daily is a reasonable amount within the ranges used in research. Some studies have used larger amounts, but taking more doesn't necessarily mean getting greater benefits.

Also, many of the cardiometabolic effects have been studied over several weeks. That's why it makes more sense to think of spirulina as a functional food you incorporate regularly into your diet, rather than expecting an immediate magic effect.

To get the most out of its benefits, you can add it to smoothies, juices, bowls, or cold preparations, since heat can degrade some of its components.

Its flavor can be quite intense and slightly marine, so you can pair it with acidic, aromatic flavors like pineapple, lemon, lime, or ginger.

You can also pair it with cacao, banana, vanilla, and nut butters. And remember that quality should always be the first thing you look at, since not all brands are the same.

Cyanobacteria can concentrate contaminants present in the environment where they're grown, and in low-quality products, there can be contamination with other cyanobacteria capable of producing microcystins — toxins that are potentially harmful to the liver.

That's why I wouldn't choose a spirulina just because it says "organic" or "superfood."

I'd look for 100% spirulina of known origin, grown under controlled conditions, and, if possible, with independent testing that includes lead, cadmium, mercury, arsenic, microcystins, and microbiological contamination.

2. CHLORELLA

Chlorella is different. Here we're actually talking about a unicellular green microalga. In other words, a microscopic organism made up of a single cell.

One of its distinctive features is that it has a tough cell wall. Because of this, when buying chlorella as a supplement, it's worth looking for products labeled "broken cell wall" or "cracked cell wall." Basically, this means that wall has been broken to make it easier to access the nutrients it contains.

What are its benefits?

Chlorella is an extremely concentrated food. It's rich in protein and essential amino acids, chlorophyll, iron, folate, and carotenoids like lutein and beta-carotene.

Something particularly interesting is that certain chlorella strains contain biologically active vitamin B12, unlike spirulina, which mainly contains B12 analogs that our body can't use in the same way. That said, the amount of B12 varies enormously between products, so it shouldn't be used to replace a B12 supplement when there's a deficiency.

Cardiovascular health. This is one of its best-supported benefits. A meta-analysis of 19 randomized controlled trials with 797 participants found that chlorella supplementation produced small but significant reductions in total cholesterol, LDL, blood pressure, and fasting glucose. Some results were more pronounced with doses above 4 g daily and over eight weeks or more.

Antioxidants and inflammation. Some human trials have found improvements in antioxidant defenses and reductions in certain oxidative stress markers. Its carotenoids, chlorophyll, and other bioactive compounds likely contribute to these effects.

Immune system. One small clinical trial found that four weeks of supplementation increased salivary IgA secretion, one of the components of our first line of immune defense in the mucous membranes. It's an interesting result, though we still need larger studies before claiming that chlorella "boosts the immune system."

Metabolism and liver. There are also preliminary studies suggesting possible benefits for insulin resistance and certain markers associated with fatty liver. The results are promising.

And the famous "detox"?

Chlorella has components capable of binding to certain metals and contaminants, which is why some functional medicine doctors, including Dr. Mark Hyman, use it as part of protocols meant to support the body's natural detoxification processes. However, even though there's promising experimental evidence, we still lack large human clinical trials proving that chlorella alone removes clinically relevant amounts of heavy metals.

How to take it

There's no official dose, but clinical studies have used different amounts. For everyday use, 4–5 g daily is a reasonable amount within the studied ranges, and some cardiometabolic benefits have been observed especially with doses above 4 g daily over eight weeks or more.

You can start with 1–2 g and increase gradually to avoid digestive discomfort.

Remember, as with everything, quality really matters here. Microalgae can concentrate substances present in the water where they grow. That's why it's important to choose a chlorella from an excellent source.

Ideally, it should be 100% chlorella, with a mechanically broken cell wall, and independent testing for lead, cadmium, mercury, arsenic, and microbiological contamination.

3. BLUE SPIRULINA

Despite its name, blue spirulina isn't another spirulina species or a new type of algae. It's an extract obtained from green spirulina, concentrated mainly in phycocyanin, the pigment-protein responsible for its spectacular blue color.

Put simply: green spirulina is the whole food; blue spirulina concentrates mainly its blue part.

What does it give us?

Phycocyanin is a pigment-protein that spirulina uses to capture light during photosynthesis.

It has antioxidant and anti-inflammatory properties, and researchers are also investigating possible hepatoprotective, renoprotective, and neuroprotective effects, as well as its effects on vascular function, lipid metabolism, and platelet aggregation.

Is it better than green spirulina?

Not necessarily. They serve different purposes.

Spirulina offers nutritional density because it retains all its nutrients, but if what you're looking for is a concentrated source of phycocyanin, then blue spirulina is the answer.

How to take it

There's still no established therapeutic dose for blue spirulina. On top of that, phycocyanin concentration can vary enormously between products.

One of the few small human studies available used around 1 g of phycocyanin per day, but it was a safety study and doesn't prove that's the ideal dose.

That's why I'd look for products that clearly state how much C-phycocyanin they contain, rather than just going by grams of powder.

Phycocyanin is fairly sensitive to heat and very acidic environments, so it's best consumed in cold or room-temperature preparations: smoothies, bowls, yogurt, puddings, cold lattes, or no-bake desserts.

Important precautions

• People with autoimmune conditions (lupus, rheumatoid arthritis, multiple sclerosis) should consult their doctor before taking chlorella or spirulina, since they can stimulate the immune system.
• Chlorella contains vitamin K, so it may interact with blood thinners like warfarin.
• It's recommended to choose brands that certify the absence of heavy metal contamination or cyanotoxins (microcystins), since both can absorb contaminants from the water they're grown in if there isn't proper quality control.
• None of these supplements should be used as the sole treatment for an actual heavy metal poisoning; that diagnosis and treatment require medical supervision.

Note: This article is for informational and educational purposes only and doesn't replace the advice of a healthcare professional. If you take medication, are pregnant, breastfeeding, or have a pre-existing medical condition (especially autoimmune, kidney-related, or a clotting disorder), talk to your doctor before adding spirulina, chlorella, or blue spirulina to your routine.