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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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
MedicationsHydrochlorothiazide and Losartan
Well established. The evidence for the two parts is strong but different.
2026-09-29 · 20 min read
MedicationsHydrochlorothiazide
Hydrochlorothiazide lowers blood pressure, but the big outcome trial that made thiazides first-line, ALLHAT, used chlorthalidone, not hydrochlorothiazide.
2026-09-29 · 12 min read
MedicationsHydroxyzine
The best evidence is a 2010 Cochrane review of five randomised trials in generalised anxiety disorder: hydroxyzine beat placebo.
2026-09-29 · 12 min read
MedicationsInsulin aspart
The evidence is that insulin aspart does the same job as regular human insulin, slightly better on average and slightly faster, not that it is a different kind of treatment.
2026-09-29 · 16 min read
MedicationsInsulin Glargine
Well established. It lowers blood sugar.
2026-09-29 · 10 min read
ResearchIntestinal permeability and "leaky gut": what is established, how it is measured, and what the supplements sold for it show
Increased permeability is a measurable finding in celiac disease and inflammatory bowel disease, and in stress states such as NSAID use and endurance exercise.
2026-09-29 · 12 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