Greens Powder

Greens powders are the marketing success story of the supplement industry, not the evidence story. The category exploded past $1B in annual sales largely on the back of AG1's celebrity-podcaster spend, with Bloom and a dozen TikTok-marketed competitors following. The clinical trial base for whole-product greens blends is thin - most published studies are short, small, single-arm, or industry-funded, and they almost never test the actual finished product against placebo.

Where the evidence is reasonable: spirulina, chlorella, beet root, moringa, and several other constituent ingredients have individual RCTs supporting modest effects on blood pressure, oxidative stress, or polyphenol intake. A handful of small trials on commercial greens blends (Juice Plus+, Berry Greens, Nutrient Dense Powder) have shown improvements in serum carotenoids and antioxidant status in adults who consume few fruits and vegetables. That is the most defensible claim in this category - greens powders raise blood polyphenol and antioxidant marker levels in low-produce-intake adults.

Where the evidence is weak or absent: virtually every other claim. "Boosts energy" - placebo-controlled trials are rare and most show no effect once caffeine content is adjusted for. "Improves immunity" - no whole-product RCT supports this at clinically meaningful endpoints. "Detoxifies" - this is a marketing word, not a measurable clinical outcome; your liver and kidneys handle detoxification. "Replaces a serving of vegetables" - false on multiple counts: a typical scoop provides 1-3g of fiber versus the 25-38g daily recommendation, and the matrix effects of whole produce (chewing, satiety, fiber-bound polyphenols, water content) are not replicated by powdered extracts. "Better than a multivitamin" - usually false, because most greens powders bury their actual vitamin and mineral amounts inside proprietary blends, while a USP-verified multivitamin discloses every dose.

The proprietary-blend problem is the single biggest issue in the category. AG1, Bloom, Amazing Grass, Macro Greens, and most competitors group ingredients into named blends ("Alkaline Greens Blend," "Antioxidant Blend," "Mushroom Complex") with only a total weight disclosed. This makes it mathematically impossible to verify whether any single ingredient hits the dose used in its supporting studies. A 2g "adaptogen blend" containing ashwagandha, rhodiola, and reishi cannot deliver the 600mg of ashwagandha used in stress-reduction trials. Buyers are paying for ingredient names on a label, not clinical doses.

Third-party testing is the second issue. Of the 14 products reviewed here, only AG1 carries NSF Certified for Sport - and even AG1 has been the subject of scrutiny over heavy metals and the gap between marketing claims and the actual published certificate of analysis. Bloom, Live It Up, Naked, Macro Greens, Sunwarrior, and most others are not independently certified.

Practical takeaway: if you eat 2+ cups of vegetables and 1-2 fruits per day, a greens powder will not move the needle on any health outcome and is one of the lowest-ROI supplement categories. If your diet runs on takeout, processed food, and minimal produce, a greens powder is a reasonable convenience product to raise polyphenol intake - but it does not substitute for actually eating vegetables, and you should pick one with disclosed doses and third-party testing rather than the loudest brand.