The single most useful fact about this category is an absence: not one published trial has compared a greens powder against actually eating vegetables. The comparator in every study is a maltodextrin placebo, never broccoli. So the specific claim these products are bought for has no direct evidence in either direction. What we can tell you is what the trials that do exist measured, who paid for them, what a scoop actually contains, and how much of it the label is allowed not to disclose. Our previous version of this page said we had tested six powders on taste and nutrient density. We had not, and that claim has been removed.
How we sourced this · not medical advice. Health Britannica does not operate a laboratory. Trial registrations were read from ClinicalTrials.gov, product composition from the NIH Dietary Supplement Label Database, nutrient comparisons from USDA FoodData Central, certification from the NSF Certified for Sport database, and enforcement records from the California Attorney General's Proposition 65 notice database, all on 30 July 2026. Our method is on the methodology page. Some links are affiliate links that support this site at no cost to you and never change our rankings.
The fiber reality: one AG1 serving supplies 2 g of fiber, about 7% of the 28 g daily value. That is slightly less than one cup of raw chopped broccoli.
The disclosure reality: roughly 86% of the 12 g scoop is declared only as four proprietary blend totals, which is entirely legal and tells you nothing about individual doses.
Certification: AG1 is verified NSF Certified for Sport, including Next Gen. That is a banned-substance and label-accuracy mark, not an efficacy one.
If you want the benefits of vegetables: the honest recommendation is vegetables, and a greens powder as a supplement to them rather than a substitute.
What does the research on greens powders actually show?
AG1 is the most-studied product in the category and its trial register is public. Searching ClinicalTrials.gov by sponsor returns eight registrations, all sponsored by the manufacturer, and zero from an independent sponsor. The largest completed trial enrolled 105 participants. Five of the eight are 30 participants or fewer. None has a hard clinical endpoint; the outcomes are nutrient biomarkers, stool microbiome composition, and questionnaires.
Two are published. A 2024 trial in 30 people over four weeks reported enrichment of two bacterial species; its digestive quality-of-life difference did not reach significance at p=0.058, which is a trend and not a result. Its funding statement reads "this research was funded in part by AG1" and two authors are company employees. The authors themselves flag that a maltodextrin placebo is of questionable validity in a microbiome study. A 2026 crossover trial in 20 resistance-trained adults over 14 days found participants met about 2.8 more estimated average requirements than placebo; it was AG1-funded with five company employees among the authors.
None of this makes greens powders useless. Closing micronutrient gaps is a real thing to do. It does mean the category has been studied at pilot scale, briefly, on surrogate markers, by the companies selling it, and the marketing claim "one of the most clinically researched green nutrition powders on the market" can be literally true while telling you mostly how little the category has been researched.
Can a greens powder replace vegetables?
Nobody has tested it. That is the honest answer and it is worth sitting with, because the entire product concept rests on a comparison that has never been run.
What we can do is compare the numbers directly, and here the arithmetic is unforgiving. Per the NIH label database, one AG1 serving contains 2 g of dietary fiber, 7% of the 28 g daily value. Per USDA FoodData Central, one cup of raw chopped broccoli contains about 2.37 g. So a $2.63 scoop delivers slightly less fiber than a cup of broccoli, and reaching the daily value from the powder alone would take about 14 servings a day.
Fiber is not the only thing vegetables provide, but it is the one most cleanly quantified, and it is the component a powdered concentrate is least able to deliver. The Cleveland Clinic's dietitian puts the practical position plainly: "You never want powdered greens to take the place of eating whole fruits and vegetables. Think of powdered greens as a bonus."
Two attributions we want to explicitly not make, because they circulate widely and we could not substantiate either: Harvard's nutrition source says nothing about powders substituting for produce, and the Academy of Nutrition and Dietetics has no position on this category.
What the label is allowed not to tell you
AG1's label declares four proprietary blends: an Alkaline Nutrient-Dense Raw Superfood Complex at 7,388 mg, a Nutrient Dense Extracts, Herbs and Antioxidants blend at 2,732 mg, a Digestive Enzyme and Super Mushroom Complex at 154 mg, and Dairy Free Probiotics at 38 mg.
That totals 10,312 mg of a 12,000 mg serving, roughly 86% of the product by weight, disclosed as four undifferentiated numbers. Under 21 CFR 101.36(c), a proprietary blend need only declare the blend's total weight and list its ingredients in descending order of predominance. This is entirely legal and extremely common.
The consequence for a buyer is specific: you can learn that ingredient A outweighs ingredient B, and that A plus B plus C weigh 7,388 mg together, but never how much of any single ingredient you are getting. A "75+ ingredients" count is not accompanied by 75+ disclosed doses, and no dose in a blend can be compared against the dose used in research. That is why full-disclosure labels are the axis we rank on below.
Are greens powders contaminated with lead?
This deserves careful framing, because the signal is real and the loudest version of it is overstated.
The California Attorney General's Proposition 65 notice database returns 20 notices naming greens powders and lead, heavily concentrated in 2026. That volume is a genuine category signal, and the mechanism is uncontroversial: these products concentrate soil-grown plant material, and lead concentrates with it.
But a 60-day notice is an allegation by a private enforcer, not a finding of harm and not a regulatory action. One private enforcer filed 15 of the 20, nearly all bundling Amazon as a co-defendant, which is a pattern characteristic of bulk enforcement litigation rather than targeted safety investigation. Prop 65's lead threshold of 0.5 micrograms a day is far stricter than federal limits and carries a large built-in safety margin. Exceeding it triggers a labeling requirement, not a hazard determination.
AG1 itself has no Prop 65 notice on file as of July 2026, which distinguishes it from much of the category. And one widely circulated figure, that AG1 contains 2.1 micrograms of lead per scoop, we could not trace to any primary lab report or testing organisation and are not repeating as fact. The most-cited category testing, which reported 18 of 37 spirulina and greens products over Prop 65 lead limits, was funded by a company that directly competes with the imported products it tested, which has to be disclosed alongside it.
One consistent and counterintuitive pattern across all this testing: organic products tested higher for lead than conventional, because organic certification governs pesticide and fertiliser inputs, not soil metal content.
If you want one anyway, which?
We rank on the two axes that are actually checkable in this category: dose disclosure and independent certification. We do not rank on efficacy, because the evidence to do so does not exist.
The bottom line
Greens powders are a convenience product sold as an insurance product. The convenience is real. The insurance is unevidenced, and the arithmetic on the one nutrient that is easy to count is not close: 2 grams of fiber against a 28 gram target, from a scoop costing more than the broccoli that beats it.
If you are already running a targeted Foundation Stack, a greens powder duplicates parts of it at a premium and adds a large undisclosed fraction. If you are not eating vegetables, the powder is not the fix, though it is not nothing either. And if you want to know exactly what your current stack costs and covers, our stack calculator will price it against the alternatives.
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