PRL-8-53: The Only Human Trial
A memory compound from a Creighton University lab in the 1970s. Its human evidence is a single double-blind trial, published in 1978, with no replication on PubMed since.
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How Does PRL-8-53 Work?
PRL-8-53 is methyl 3-[2-[benzyl(methyl)amino]ethyl]benzoate hydrochloride, one of a series of aminoethyl meta-benzoic acid esters made by medicinal chemist Nikolaus Hansl at Creighton University and covered by US Patent 3,870,715 (granted 1975).
The patent describes the series as useful "as spasmolytics, psychotherapeutic agents and agents facilitating learning", and as cholinergic agents. Those are the inventor's claims. No later published study has mapped a receptor target or mechanism.
The patent reports rat avoidance tests (electric-shock negative reinforcement) and water-reward maze tests in which the compound sped up acquisition and increased later retention. A 1974 Experientia paper introduced it as a novel spasmolytic and CNS-active agent.
The patent lists an oral lethal-dose figure of about 500-700 mg/kg in mice, reproduction studies over two offspring generations with no malformations found, and tolerance in dogs and monkeys at doses as high as 50 mg/kg. All of it is 1970s inventor data, not modern safety testing.
What the Data Shows
Key Takeaways
- One double-blind, placebo-controlled human trial exists: Hansl & Mead, Psychopharmacology, 1978 (PMID 418433).
- That trial reported a slight improvement in learning and statistically significant gains in retention of verbal information.
- Visual reaction time and motor control did not differ from placebo in the same trial.
- The inventor's patent reports faster learning and better retention in rat avoidance and maze tests.
- Patent toxicology: an oral lethal-dose figure of about 500-700 mg/kg in mice, and tolerance up to 50 mg/kg in dogs and monkeys.
- Whether the 1978 result holds up. PubMed lists no follow-up human study by any group.
- How it works. The patent calls it cholinergic, but no receptor or mechanism study has been published.
- The right human dose. The trial title says only "low oral doses"; the dose itself sits in the paywalled full text.
- Long-term safety, drug interactions, and effects in people with medical conditions.
- Whether research-chemical products today match the compound used in the 1970s studies.
Frequently Asked Questions
What is PRL-8-53?
PRL-8-53 is a synthetic compound, methyl 3-[2-[benzyl(methyl)amino]ethyl]benzoate, made by medicinal chemist Nikolaus Hansl at Creighton University in the 1970s. It is sold online as a nootropic research chemical. It was never developed into an approved drug, and its human evidence is a single trial published in 1978.
Does PRL-8-53 improve memory?
One double-blind 1978 trial (Hansl & Mead, PMID 418433) reported slightly better learning of verbal material and statistically significant gains in later retention compared with placebo, with no change in reaction time or motor control. No independent group has published a replication, so the finding is unconfirmed after more than four decades.
What dose of PRL-8-53 was studied?
The trial is titled as testing "low oral doses", and the abstract gives no amount. The inventor's patent claims an oral range of about 0.01 to 4 mg/kg, most preferably 0.05 to 1.2 mg/kg, for enhancing mental performance. That range is a patent claim, not a dose-finding result, and no published human study has tested dosing since.
Is PRL-8-53 safe?
Its safety record is 1970s data from the inventor's patent: an oral lethal-dose figure of about 500-700 mg/kg in mice, no malformations across two offspring generations, and tolerance in dogs and monkeys up to 50 mg/kg. The 1978 trial abstract reports no safety data; its reaction-time and motor results are performance measures, not adverse-event outcomes. Modern toxicology, interaction and long-term human data do not exist.
Is PRL-8-53 an approved drug?
No. PRL-8-53 has no FDA approval for any use, and we found no record of it reaching later clinical development. It is sold online as a research chemical, so purity depends on the vendor's own testing. Ask for a batch-specific certificate of analysis before buying any lot.
Buy PRL-8-53 (Research Grade)
Swiss Chems publishes third-party HPLC COAs for selected products (vendor-published, a claim to verify). Deep-linked to the PRL-8-53 product page.
Buy PRL-8-53 at Swiss Chems →Affiliate links support HighPeptides at no extra cost.
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PRL-8-53 is not an approved drug, and nothing on this page is a dosing recommendation.
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