- "Greens powder" and "longevity supplement" are shop-shelf categories, not scientific ones. The name tells you nothing about doses or quality.
- Greens powders usually combine dried plants with vitamins, minerals and sometimes cultures. A few products have small trials of their own; the category as a whole doesn't.
- "Longevity" ingredients (NR, NMN, spermidine, resveratrol and others) have human studies on markers, but none has shown that people live longer.
- Compare the full label: every amount, every form, cost per serving. Ignore the category name.
Walk down any supplement aisle and you'll see two tribes. One is green, earthy and promises "your daily nutrition". The other is sleek, scientific and promises to slow the clock. Increasingly, products try to be both.
Underneath the branding, you're buying a list of ingredients at certain doses. That's the only thing worth comparing.
What a greens powder usually is
Most greens powders combine dried vegetables, algae and fruit (spirulina, wheatgrass, spinach, berries) with some or all of: vitamins and minerals, fibre, live cultures, digestive enzymes and herbal extracts.
Is there evidence? More than critics claim, less than marketing implies. At least one leading product has small randomised trials of its own, looking at nutrient intake, gut bacteria and short-term blood safety markers.¹⁻³ That's useful. But these trials are small and short, measure markers rather than health outcomes, and apply only to that formula, sometimes in a different country's version.
One honest limit: a scoop of dried plant powders isn't the same as eating those plants. Whole vegetables bring fibre, water and a food structure that powders can't fully reproduce. The UK fibre target alone is 30 g a day.
What a longevity supplement usually is
"Longevity" products contain compounds studied in the biology of ageing:
- NR or NMN, precursors of NAD⁺, a molecule involved in cellular energy.
- Spermidine, linked in lab research to cellular recycling (autophagy).
- Resveratrol, urolithin A, quercetin, fisetin and others.
Is there evidence? Some of these reliably change a marker in humans. NR, for example, raises NAD⁺ in the blood.⁴ But changing a marker isn't the same as changing outcomes. A 12-month spermidine trial missed its main memory goal.⁵ A urolithin A trial saw signals on some measures but not on its main ones.⁶ No supplement has shown that humans live longer.
How to compare any product, in five questions
- What's the full ingredient list, with every amount? Avoid blends that hide individual doses.
- Which forms? Methylfolate or folic acid, D3 or D2, which magnesium salt, what extract standardisation.
- Does it cover the basics? Vitamin D, iodine and K are missing from some daily formulas. Check what's in the scoop itself, not in a separate add-on.
- What's the real cost per serving? Divide price by servings. Watch billing every 4 weeks versus 30-day supplies, and one-off prices versus subscription.
- Is it independently tested, and does the certificate apply to the UK product?
Where 4VIA sits
We built 4VIA to cover both halves: daily nutrition you notice, and ingredients studied for healthy ageing, in a morning drink and a night capsule. You get both on one label, with every dose listed, so you can compare it the same way.
References
- La Monica MB et al. J Int Soc Sports Nutr. 2024;21:2409682. doi:10.1080/15502783.2024.2409682
- Gonzalez AM et al. Front Nutr. 2026. PMID 41988471
- Wood A et al. J Int Soc Sports Nutr. 2025;22(Suppl 2):2550153
- Conze D et al. Sci Rep. 2019;9:9772. doi:10.1038/s41598-019-46120-z
- Schwarz C et al. JAMA Netw Open. 2022;5:e2213875
- Liu S et al. JAMA Netw Open. 2022;5:e2144279 NHS. How to get more fibre into your diet (30 g/day).
