From Memios
The Longevity Letter
Practical writing and video on living strong and active into your 90s. No hype, no supplements to sell. Just what the evidence supports and what it looks like on an ordinary Tuesday.
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SupplementsGreen tea extract / EGCG
This is one of the clearest cases in the supplement literature where the harm evidence is stronger than the benefit evidence.
2026-09-29 · 20 min read
SupplementsHawthorn
Disputed. The evidence is genuinely split.
2026-09-29 · 20 min read
SupplementsHMB
Limited evidence. The evidence points in different directions depending on who takes it.
2026-09-29 · 11 min read
SupplementsHoly basil / tulsi
Limited evidence. Lead with the state of the evidence: it is weak and probably one-sided.
2026-09-29 · 13 min read
SupplementsHoodia
Not supported by the research. The human evidence does not support a weight or appetite effect.
2026-09-29 · 10 min read
SupplementsHorny goat weed
Limited evidence. Almost all of the pharmacology is preclinical.
2026-09-29 · 17 min read
SupplementsHorse chestnut
Horse chestnut seed extract is one of the better-supported herbal treatments for one narrow purpose: the leg symptoms of chronic venous insufficiency.
2026-09-29 · 13 min read
SupplementsHuperzine A
Disputed. The evidence is disputed rather than settled.
2026-09-29 · 14 min read
SupplementsInulin and other inulin-type fructan prebiotics
Inulin reliably feeds and increases bifidobacteria in the gut: a 50-trial meta-analysis found a clear rise.
2026-09-29 · 12 min read
SupplementsIodine
The thyroid needs iodine to make its hormones, which control growth and brain development.
2026-09-29 · 9 min read
SupplementsIron
The evidence is strong that iron supplements correct iron deficiency and anaemia: a Cochrane review of 67 trials in menstruating women found less anaemia, higher haemoglobin, better exercise performance and less fatigue.
2026-09-29 · 10 min read
SupplementsKava
Disputed. Kava is sold for anxiety, and the evidence is genuinely split.
2026-09-29 · 19 min read
SupplementsKefir and kefir grain cultures
Limited evidence. The evidence is limited.
2026-09-29 · 10 min read
SupplementsKratom
Disputed. There are almost no controlled human efficacy trials.
2026-09-29 · 13 min read
SupplementsL-theanine
The best-supported effect is narrow and short-lived: a single dose of around 200 mg improves one measure of attention in healthy adults within an hour.
2026-09-29 · 12 min read
SupplementsL-tryptophan
As a nutrient it is not optional; as a supplement the evidence is modest and the safety history is serious.
2026-09-29 · 18 min read
SupplementsL-tyrosine
The claim is that extra tyrosine supports thinking under pressure, and the review literature partly backs that while narrowing it sharply.
2026-09-29 · 18 min read
SupplementsLactase enzyme supplements
Lactase supplements reduce the hydrogen gas that signals undigested lactose and modestly reduce symptoms in trials.
2026-09-29 · 8 min read
SupplementsLacticaseibacillus paracasei and Lacticaseibacillus casei
Limited evidence. The evidence is strain-specific and limited.
2026-09-29 · 11 min read
SupplementsLactiplantibacillus plantarum
Disputed. The evidence is strain-specific and mixed.
2026-09-29 · 11 min read
SupplementsLacticaseibacillus rhamnosus GG
The best evidence is for reducing antibiotic-associated diarrhoea in children (moderate-quality pooled evidence); in adults the pooled result was not significant.
2026-09-29 · 11 min read
SupplementsLicorice root
Limited evidence. The best evidence concerns harm.
2026-09-29 · 11 min read
SupplementsLion's mane
The honest summary is that almost all of the biology behind lion's mane's reputation is cell-culture and rodent work, and the human evidence is a handful of small, short trials with inconsistent results.
2026-09-29 · 20 min read
SupplementsLutein and zeaxanthin
Limited evidence. The evidence is limited and mostly about the eye.
2026-09-29 · 20 min read