ACD856

guinea pig

Also seen as: ACD-856, ACD 856, acd

The Dose Guy’s verdict

Sep 1, 2026
3 sources

The mechanism is one of the more interesting ones on this shelf: a small molecule that amplifies your own neurotrophin signaling instead of trying to supply it from outside. Phase 1 safety data looks clean. But ACD856 has never been tested for cognitive efficacy in a person, and the compound is still in pharma development, not available as a research chemical people can realistically source. If the neurotrophic angle is what drew you here, alpha-GPC is sourceable and has human trial data behind it. Watch this one. Don’t run it yet.

Would I take it?Promising, but far too early to run.

What it is

A positive allosteric modulator of the Trk receptors, the ones that NGF and BDNF bind to drive neuron growth, survival, and plasticity. Where most nootropic compounds try to increase a neurotrophic signal, ACD856 amplifies the signal you already have: it makes TrkA and TrkB more responsive to whatever NGF and BDNF your brain is already producing. The animal cognition results are striking, and two phase 1 trials confirmed it reaches the brain and shifts EEG patterns. That is real pharmacology, not a vendor claim. It is also not a cognitive outcome.

ACD856 comes from AlzeCure Pharma in Sweden. The development target is Alzheimer’s disease, not healthy-person enhancement. Whether the mechanism translates to the healthy brain is an open question that has not been asked in any trial yet.

What the research shows

Phase 1 safety and pharmacokinetics in healthy volunteers. Strong animal cognition data. No human efficacy trial yet:

Single oral doses from 1 to 150 mg were well tolerated in 56 healthy subjects, with no treatment-emergent or dose-related adverse events. Absorption was rapid and bioavailability nearly complete.Eur J Clin Pharmacol 2024 · phase 1 · n=62

Seven days of daily dosing at 10 to 90 mg was well tolerated in 24 healthy subjects, with no serious adverse events. ACD856 reached steady state by day 6, crossed into cerebrospinal fluid in a dose-dependent way, and produced significant dose-dependent EEG changes.J Prev Alz Dis 2023 · phase 1 · n=24

A single ACD856 dose restored cognitive function in 18-month-old mice to the level of 2-month-old mice.Cells 2021 · discovery · animal

No human efficacy trial exists. The cognitive restoration shown in aged mice has not been tested in a person.as of Aug 2026

Realistic protocols

ACD856 is a pharma-stage compound still in clinical development. It is not available as a consumer research chemical, and no human has taken it for cognitive enhancement outside a controlled trial setting. I’m not writing a protocol for a compound nobody can source or self-administer. If you find it anyway, go low, go short, log everything. If it reaches later-stage trials with cognitive endpoints, this page will change.

Side effects

Phase 1 safety data is clean but thin, 56 on single oral doses and 24 dosed for a week:

unknownNo treatment-emergent adverse events identified at any dose in either the single-dose or seven-day trial. That is a good sign, not a guarantee.

unknownEighty people total, seven days maximum. No long-term data, no data in older adults, no data at doses or durations relevant to cognitive enhancement. A clean phase 1 is a start, not a guarantee.

Where to buy

No live listings from tracked vendors right now.