Phase I double-blind, placebo-controlled, randomised study (n=48) of very low-dose LSD (5, 10, 20 µg) or placebo given six times over 21 days in healthy volunteers aged 55–75.
Randomised, quadruple-blind, parallel-group study comparing three very-low-dose LSD regimens (5, 10, 20 µg) to placebo; dosing on Study Days 1, 5, 9, 13, 17 and 21 with a follow-up ~4 weeks after last dose.
Outcomes explored pharmacodynamic effects on cognition, affect, memory, temporal perception, executive function, learning, subjective effects, proprioception and balance, plus safety and tolerability measures.
Very-low-dose LSD 5 µg given six times over 21 days (days 1,5,9,13,17,21).
Very-low-dose LSD 10 µg given six times over 21 days (days 1,5,9,13,17,21).
Very-low-dose LSD 20 µg given six times over 21 days (days 1,5,9,13,17,21).
Matching placebo given on same schedule (6 doses over 21 days).
Matching placebo
In a phase 1 double‑blind, placebo‑controlled trial in 48 healthy older volunteers (mean age 62.9), oral low doses of LSD (5, 10 and 20 μg) given every fourth day for 21 days produced undetectable plasma levels at 5 μg and 30‑minute peak concentrations at 10 and 20 μg. The regimen was well tolerated with adverse event rates similar to placebo and no detectable impairment of cognition, balance or proprioception, supporting further evaluation of LSD for prevention or treatment of Alzheimer’s disease.