Which supplements for memory have published, product‑level randomized controlled trials listed on ClinicalTrials.gov?

1. Multivitamin: the clearest product‑level, registered RCT

A large, product‑level, randomized clinical trial tested a specific multivitamin formulation (Centrum Silver) within the COSMOS-Web ancillary study, and that trial is explicitly registered at ClinicalTrials.gov under NCT04582617 and published with positive effects on immediate verbal recall in older adults ^{[1] [2] [3]}. The NIH summarized the study design and outcomes, noting the randomized, placebo‑controlled, internet‑based neuropsychological battery and the participant pool of >3,500 older adults, making this the clearest example in the supplied reporting of a published product‑level RCT tied to a ClinicalTrials.gov record ^{[11] [2]}.

2. Ginkgo biloba: large RCTs exist but registration details not clarified in provided sources

Ginkgo biloba has been the subject of several randomized trials, including the large Gingko Evaluation of Memory (GEM) study that randomized more than 3,000 participants and long‑term follow‑up, and meta‑analyses report modest benefits in some settings ^{[5] [12]}. However, the documents supplied describe trial outcomes and meta‑analyses without explicitly showing ClinicalTrials.gov identifiers or confirming that these were product‑level trials tied to a single commercial extract (EGb‑761) in the ClinicalTrials.gov registry within the provided snippets ^{[5] [12]}. Thus, while ginkgo is well studied, the specific question — published, product‑level RCTs listed on ClinicalTrials.gov — is not fully resolved by the supplied reporting.

3. Bacopa (B. monniera / KeenMind®): randomized evidence exists but registry linkage is unclear

Randomized, double‑blind, placebo‑controlled trials of Bacopa monniera — including studies of a branded extract (KeenMind®) showing improvements in memory consolidation and information processing — are reported in reviews of randomized trials ^[6]. Those publications demonstrate product‑level testing in peer‑reviewed studies, but the supplied excerpts do not document ClinicalTrials.gov registration numbers or make explicit that the published trials are listed on ClinicalTrials.gov ^[6]. Registry confirmation is therefore not available in the supplied material.

4. Other nutrients and botanicals: mixed RCT evidence, limited registry confirmation

B‑vitamin trials, vitamin D, vitamin E, curcumin, ashwagandha, berry extracts, and many other nutraceuticals appear across systematic reviews and individual randomized trials with mixed results — some positive, many null or variable depending on population and endpoints ^{[4] [13] [8] [7] [10] [9]}. Several reviews note randomized trial evidence for these agents, and some trials are product‑specific; nevertheless, the provided reporting does not consistently show ClinicalTrials.gov identifiers for product‑level trials of these supplements, so registry‑level confirmation cannot be asserted based on the supplied sources ^{[13] [4]}.

5. What the reporting reveals — and what it does not

The supplied literature demonstrates that many supplements have been tested in randomized controlled trials and that a scattering of product‑level studies exist in the peer‑reviewed literature ^{[6] [5] [12]}. However, only the Centrum Silver multivitamin trial is explicitly documented in these snippets as a published trial with a ClinicalTrials.gov registration number (NCT04582617) ^{[1] [2] [3]}. For other commonly touted memory supplements, the reporting cites RCTs and meta‑analyses but does not provide the ClinicalTrials.gov registration details necessary to answer, with registry evidence, whether those trials were product‑level and listed on ClinicalTrials.gov ^{[4] [5] [6]}. Independent verification on ClinicalTrials.gov or review of the primary publications for registration numbers would be required to expand the definitive list.