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Research · Supplements

Greens powders

Short trials of AG1, each with employees of its maker among the authors, found raised blood levels of most nutrients tested, more nutrient targets met and shifts in a few gut bacteria. A 30-day trial of another greens product found no change in metabolic markers or body composition. Algae ingredients carried pharmaceutical residues and cyanotoxins in product testing.

Add to Bio HackChecked 2026-11-09
Status
Dietary supplements in the US. Multi-ingredient blends vary by brand.
Also called
AG1, Athletic Greens, super greens, greens supplement, superfood powder, fruit and vegetable powder, juice powder concentrate, spirulina, chlorella
Taken for
nutrient gaps, gut health, energy, immunity, digestion, aging, replacing fruit and vegetables

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help3

Reported risks1

What people take it for, and what was found

Shown to help3

Limited

Nutrient intake and absorption

Small trials with AG1 employees as authors found one serving raised blood levels of several vitamins and minerals. Health outcomes were not measured.

The numbers and sources
Effect
In 16 healthy adults, one 13 g serving of AG1 raised blood levels over 8 hours (AUC) for folate, calcium, zinc, vitamin C, biotin, nicotinamide, riboflavin, thiamine and hesperidin compared with placebo. Pyridoxine showed a weak trend [1]. In 20 resistance-trained adults, 14 days of AG1 raised the number of micronutrient Estimated Average Requirements met by 2.8 compared with placebo, mostly vitamins A, C and E [2].
Population
Healthy and trained adults [1][2].
Sources
[1], [2]
Caveats
The absorption trial was funded by AG1 [1]. Five or more authors on each trial were AG1 employees [1][2]. Higher blood levels after one serving do not show a change in health outcomes.
Moderate

Weight and metabolic markers (spirulina or chlorella alone)

Shown to lower weight about 1 to 1.3 kg with spirulina or chlorella alone in adults. Reviews disagree on chlorella and cholesterol.

The numbers and sources
Effect
In 17 RCTs in adults, spirulina lowered body weight by 1.07 kg, BMI by 0.40 and body fat by 0.84 percentage points, with no significant change in waist circumference [6]. In 24 studies, chlorella lowered weight by 1.28 kg (95% CI -2.00 to -0.56), body fat by 0.73 points, LDL by 6.20 mg/dL and total cholesterol by 8.03 mg/dL [7]. A 2025 meta-analysis of 21 RCTs found chlorella had no effect on blood pressure or blood lipids. Spirulina lowered diastolic pressure by a small amount (-0.42, 95% CI -0.81 to -0.02) without a significant lipid change [8].
Population
Adults in RCTs of single-algae supplements [6][7][8].
Sources
[6], [7], [8]
Caveats
These trials tested spirulina or chlorella alone, not multi-ingredient greens blends. Certainty in [7] was very low for most outcomes and low for BMI. The reviews disagree on chlorella and lipids [7][8]. The authors of [8] call the blood pressure effect small and of uncertain clinical significance.
Limited

Energy and immunity

One trial found a fruit and vegetable juice powder cut days with moderate or severe cold symptoms by 20% in hospital staff. No trial measuring energy was located.

The numbers and sources
Effect
In 529 healthcare workers given encapsulated fruit and vegetable juice powder (Juice Plus+) or placebo daily for 8 months, days with moderate or severe cold symptoms over 6 months averaged 7.6 against 9.5 (p = 0.023). Total days with any cold symptom did not differ, 29.4 against 30.7 (p = 0.616) [11].
Population
529 hospital staff in Berlin aged 18 to 65, mostly nurses, 80% women [11].
Sources
[11]
Caveats
One trial of one encapsulated fruit and vegetable product, not a greens drink powder. Symptoms were self-reported in diaries, and the effect was limited to more severe symptom days [11]. No trial of AG1 or other greens blends measured energy, fatigue or infections.

Mixed results1

Limited

Gut bacteria

Small trials found a few gut bacteria changed, with no change in overall diversity or digestive quality of life.

The numbers and sources
Effect
In 30 healthy adults, 4 weeks of AG1 enriched two probiotic species present in the product and reduced one Clostridium species. Digestive quality of life, bowel frequency and stool consistency were not worsened, and a possible DQLQ improvement did not reach significance (p = 0.058) [3]. In the 14-day trial, alpha and beta diversity did not shift, a few taxa rose, and digestive quality of life did not differ from placebo (p = 0.777) [2]. In 21 obese adults aged 50 to 65 on a different greens supplement for 30 days, alpha diversity was unchanged and two taxa changed [4].
Population
Healthy adults [2][3]. Obese older adults [4].
Sources
[2], [3], [4]
Caveats
Two AG1 employees were authors of the 4-week trial [3]. Changes in taxa are not health outcomes.

Not shown to help1

Limited

Markers of aging and metabolic health

Small trials found no change in body composition or metabolic markers. One epigenetic clock rose while newer clocks trended toward improvement.

The numbers and sources
Effect
In the 30-day greens trial, Horvath epigenetic age increased during supplementation, while newer clocks trended toward improvement. Body composition, metabolic biomarkers, sleep and psychosocial measures did not change [4]. In 34 older adults, 6 months of a fruit, vegetable and berry juice powder concentrate in capsules kept homocysteine stable against a rise in controls, and diastolic blood pressure differed between groups after adjustment [5].
Population
Obese adults aged 50 to 65, 19 completing [4]. Generally healthy older adults [5].
Sources
[4], [5]
Caveats
Small trials. The juice powder trial was open-label, and two authors were affiliated with the Green Beat Institute of Nutrient Research [5].

Doses studied

AG1 trials used one 13 g serving a day [1], for 14 days [2] or 4 weeks [3]. The other greens trial used a daily serving for 30 days [4]. The juice powder trial used six capsules a day for 6 months [5].

Risks

Reported risks1

Limited

Contaminants in algae ingredients

Limited evidence: tests of spirulina and chlorella products found drug residues and cyanotoxins, though all met EU limits for toxic metals.

The numbers and sources
Effect
In 52 spirulina and chlorella supplements, all met EU limits for toxic metals, but pharmaceutical residues were found, most often caffeine, then metronidazole, carbamazepine, benzocaine and tramadol. Aluminum intake was flagged against the tolerable weekly intake. Organic and conventional products did not differ [9]. In spirulina and klamath supplements, several cyanotoxins were detected, with high microcystin-RR in one klamath product [10].
Population
Product testing of single-algae supplements [9][10].
Sources
[9], [10]
Caveats
These tested algae products, not multi-ingredient greens blends.

Checked, no increase found1

Limited

Safety markers in trials

Limited evidence: small trials found no change in blood count, liver, kidney or metabolic markers, and no serious adverse events.

The numbers and sources
Effect
AG1 did not significantly change blood count, metabolic panel or lipid markers over 4 weeks [3], and no serious adverse events were reported after a single serving [1]. Six months of the juice powder concentrate showed no deterioration in liver, kidney, thyroid, lipid or glucose markers [5].
Population
Healthy adults [1][3]. Older adults [5].
Sources
[1], [3], [5]
Caveats
Trials ran from one day to 6 months with 16 to 34 participants, too small to detect uncommon harms.

Not yet researched1

No research yet

Contaminants in multi-ingredient greens blends

We haven't sourced research on this yet.

Claims tested and not found

  1. That greens blends improve body composition or metabolic markers. In the one blend trial located, body composition and metabolic biomarkers did not change over 30 days [4].
  2. That AG1 improves digestive quality of life. Digestive quality of life did not differ from placebo over 14 days (p = 0.777) [2].

Sources

  1. Sapp PA, Townsend JR, Kirby TO, et al. Absorption kinetics of vitamins and minerals from a novel nutritional product in physically active adults: a randomized, double-blind, placebo-controlled crossover trial. Frontiers in Nutrition. 2026. https://doi.org/10.3389/fnut.2026.1793264
  2. Gonzalez AM, Townsend JR, Sapp PA, et al. Effect of AG1 supplementation on nutritional adequacy and gut microbial composition in trained adults. Frontiers in Nutrition. 2026. https://doi.org/10.3389/fnut.2026.1783951
  3. La Monica MB, Raub B, Hartshorn S, et al. The effects of AG1 supplementation on the gut microbiome of healthy adults: a randomized, double-blind, placebo-controlled clinical trial. Journal of the International Society of Sports Nutrition. 2024. https://doi.org/10.1080/15502783.2024.2409682
  4. Robinson LA, Cavanah AM, Lennon S, et al. Epigenetic and microbiome responses to greens supplementation in obese older adults: results from a randomized crossover-controlled trial. Frontiers in Nutrition. 2026. https://doi.org/10.3389/fnut.2026.1750030
  5. Ziegler T, Darko A, Ledinski G, et al. Effects of a Commercial Fruit, Vegetable and Berry Juice Powder Concentrate on Metabolic Safety and Cardiovascular Health in Older Adults: 6-Month Results of a Randomized Controlled Trial. Nutrients. 2026. https://doi.org/10.3390/nu18172746
  6. Lak M, Karimi M, Akhgarjand C, et al. Effects of spirulina supplementation on body composition in adults: a GRADE-assessed and dose-response meta-analysis of RCTs. Nutrition & Metabolism. 2025. https://doi.org/10.1186/s12986-025-00959-4
  7. Mardani H, Karimi MA, Sharifi M, et al. Beneficial effects of Chlorella species supplementation in the general population: a GRADE-assessed systematic review and dose-response meta-analysis. Nutrition & Diabetes. 2026. https://doi.org/10.1038/s41387-026-00449-3
  8. Pinto-Leite M, Martins D, Ferreira AC, et al. The Role of Chlorella and Spirulina as Adjuvants of Cardiovascular Risk Factor Control: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Nutrients. 2025. https://doi.org/10.3390/nu17060943
  9. Sochacka M, Kózka B, Kurek E, Giebułtowicz J. Spirulina and Chlorella Dietary Supplements: Are They a Source Solely of Valuable Nutrients? International Journal of Molecular Sciences. 2025. https://doi.org/10.3390/ijms262110468
  10. Carbonell-Rozas L, Aparicio-Muriana MM, Romero-González R, et al. Application of Targeted and Suspect Screening Workflows for Cyclic Peptide Cyanotoxin Profiling in Spirulina- and Klamath-Based Food Supplements. Foods. 2025. https://doi.org/10.3390/foods14172969
  11. Roll S, Nocon M, Willich SN. Reduction of common cold symptoms by encapsulated juice powder concentrate of fruits and vegetables: a randomised, double-blind, placebo-controlled trial. British Journal of Nutrition. 2011. https://doi.org/10.1017/s000711451000317x

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