Guide

Do Spirulina, Chlorella and Wheatgrass Actually Work?

Everyone taking a greens supplement is really buying three headline ingredients bundled with a promise. Here is what the actual research says about each one, and what it means when they are combined in a product like Grüns.

Disclosure: If you buy Grüns through my links, I may earn a commission at no extra cost to you.

What does the evidence actually say about spirulina?

More than you might expect, and more than most of the ingredients on this list.

A 2025 systematic review and meta-analysis pooling randomized clinical trials in overweight and obese adults found spirulina supplementation produced measurable reductions in body fat, LDL cholesterol, triglycerides and total cholesterol, along with a clinically meaningful drop in systolic blood pressure. A separate meta-analysis of controlled trials found reductions in inflammatory markers including CRP and IL-6, and improvements in antioxidant capacity.

The honest caveats matter too. Effects on blood sugar control were inconsistent across trials, and researchers note that optimal dose and duration are still not standardized, which makes it hard to say exactly how much or how long you would need to take it to see the same effect a study measured.

What about chlorella?

Also real, in a similar lane: modest, cardiometabolic, not dramatic.

A GRADE-assessed systematic review of 25 studies found chlorella supplementation improved dyslipidemia, lowering total cholesterol and LDL while raising HDL, and enhanced insulin sensitivity. Separate research has linked it to improved endurance markers, including lower lactate and heart rate during exercise.

Here too, the caveat is real: findings on blood lipids are inconsistent across individual trials, with some showing no significant effect, and safety reporting in certain patient populations has been described as insufficiently rigorous. This is evidence of a real, plausible effect, not proof it happens for everyone every time.

And wheatgrass, the one everyone assumes works?

This is the honest disappointment on the list.

Reviews of the clinical literature, including a reference summary from Memorial Sloan Kettering's integrative medicine database, conclude that most of wheatgrass's popular health claims are not supported by clinical studies. The trials that do exist are small and narrow: one placebo-controlled trial of 23 patients found wheatgrass juice reduced disease activity in ulcerative colitis, and some early research has looked at it as a supportive addition alongside cancer treatment. Neither is the sweeping detox or energy claim wheatgrass is marketed on.

Wheatgrass is not disproven. It is simply years ahead in marketing compared to where the research has actually gotten to. That gap between reputation and evidence is worth knowing before you pay a premium for it specifically.

What happens when you test the whole blend, not just one ingredient?

This is where it gets more useful, and also where I want to be precise about whose product was actually studied.

A 2025 randomized, triple-blind, placebo-controlled trial of AG1, a greens powder and not the product this site reviews, gave 120 adults with below-average fruit and vegetable intake either the product or a placebo for 12 weeks. The nutrient biomarker results showed real, measurable change: vitamin C rose 33%, serum folate rose 26%, and homocysteine, a marker linked to cardiovascular risk, dropped 10%. A companion safety trial found no adverse changes in standard blood panels.

But a separate gut microbiome trial on the same product found it altered the composition of gut bacteria, without a clear improvement in self-reported digestive health. And a 2026 trial of greens supplementation in older adults found body composition, metabolic biomarkers and dietary intake stayed essentially unchanged over the study period.

What makes Grüns more interesting here is that there is now product-specific clinical data, not just research on the individual ingredients. In a 12-week randomized, double-blind, placebo-controlled study of 120 adults aged 23 to 59, conducted through Citruslabs, a third-party clinical research firm, Grüns reports increases in key nutrients including folate, up 20.5%, and vitamin C, up 40.1%, compared to placebo.

Both AG1 and Grüns now have product-specific clinical research behind them, rather than relying only on general ingredient studies. The two trials measured the same kind of thing, nutrient levels in the blood, using a similar design. Neither trial tested for disease outcomes, weight loss or any other health claim beyond nutrient absorption, which is worth keeping in mind before reading either result as more than what it actually measured.

Put together, that is a genuinely fair picture: two well-formulated greens blends, each backed by its own clinical trial, both moved blood nutrient levels in ways you can measure, without either one delivering the digestive transformation or body composition change the marketing around this category implies.

So, is a greens supplement actually worth taking?

For me, yes, though not because any single ingredient produces a dramatic effect on its own. Spirulina and chlorella move real biomarkers, and both AG1's trial and Grüns' own trial show a well-formulated blend can shift folate and vitamin C levels in your blood. None of that happens from a product sitting unopened in a cupboard.

The more useful question than "does the ingredient work" is whether a specific product gives you a practical way to add nutrients, greens and fiber to your day consistently enough for any of this evidence to apply to you. That depends on dose, on formulation, and on something no trial measures directly: whether you actually keep taking it.

Whether you actually keep taking it is why format keeps coming back into this conversation. I go through the mechanics of it in gummy vs capsule absorption, and the direct trade-off between gummies and powder in greens gummies vs greens powder. According to CDC data, only 10.0% of US adults meet the federal recommendation for vegetable intake in the first place, which is the gap any of these ingredients are trying to close. None of them close it from inside a cupboard.

A note on health claims. Supplements in any format are wellness products, not medicines or medical devices. They do not treat, cure or prevent anything, and nothing here is medical advice. I am not a doctor, a nutritionist or a researcher. Talk to a professional before starting a supplement, especially if you are pregnant, nursing, taking medication or managing a health condition.

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