Effect of Nutritional Supplement Alpha-ketoglutarate for Age-related Ocular Disease (OAK AGE)

March 30, 2026 updated by: Vinit Mahajan, Stanford University

Effect of Nutritional Supplement Alpha-ketoglutarate for Age-related Ocular Disease: An Open Label, Single Arm Study to Evaluate the Effect of Alpha-ketoglutarate Administered Orally in Patients With Age-related Ocular Diseases (Metabolic Eye Therapy)

The aims of the study are as follows:

  1. Determine how the eye absorbs supplements taken orally.
  2. Look for specific signs in the proteins and substances in the eyes of people with eye diseases who are also taking nutritional supplements.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

17

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Palo Alto, California, United States, 94303
        • Byers Eye Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Able and willing to give written informed consent
  2. Able to attend all study visits and complete the study procedures
  3. Women of child-bearing potential must have a negative pregnancy test within 2 weeks before cataract surgery. A pregnancy test is not required for postmenopausal women (defined as being at least 12 consecutive months without menses) or those surgically sterilized (those having a bilateral tubal ligation/bilateral salpingectomy, bilateral tubal occlusive procedure, hysterectomy, or bilateral oophorectomy).

Exclusion Criteria:

  1. Diabetes and/or thyroid, liver, kidney, bowel, and metabolic diseases or disorders
  2. History of supplement allergy or planned major surgery
  3. Received any other clinical trial drug within 4 months
  4. Calculated creatinine clearance of less than 30 ml/min

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Calcium alpha-ketoglutarate (Ca-aKG)
At the first and second cataract surgery of the participant, a small amount of tissue (eye fluid ~0.1 ml or 1-2 drops) is removed for analysis. Beginning one week (7 days) prior to their second cataract extraction surgery, the patient takes an oral nutritional supplement (calcium alpha-ketoglutarate) 2 times a day.
Drug: Calcium alpha-ketoglutarate
Participants took 2 g/day of calcium alpha-ketoglutarate orally, twice daily, for 7 days.
Other Names:
  • Prohealth Longevity

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean change in aqueous humor aKG level
Time Frame: Baseline and post-supplementation, approximately 28 days
To evaluate the mean difference in fold-change in aKG levels from baseline to post-supplementation in eye fluid
Baseline and post-supplementation, approximately 28 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean fold-change in metabolic and retinal pathways
Time Frame: Baseline and post-supplementation, approximately 28 days
To calculate mean fold-change in retinal metabolic and protein pathways from baseline to post-supplementation in eye fluid
Baseline and post-supplementation, approximately 28 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Stanford University

Investigators

  • Principal Investigator: Vinit Mahajan, MD, PhD, Stanford University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 15, 2023

Primary Completion (Actual)

June 10, 2025

Study Completion (Actual)

June 10, 2025

Study Registration Dates

First Submitted

November 25, 2025

First Submitted That Met QC Criteria

November 25, 2025

First Posted (Actual)

December 8, 2025

Study Record Updates

Last Update Posted (Actual)

April 3, 2026

Last Update Submitted That Met QC Criteria

March 30, 2026

Last Verified

October 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 68157

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Age, sex, BMI, Medical history, ocular history

IPD Sharing Time Frame

The data will be made available upon study registration with CTgov, and will remain available for at least 5 years.

IPD Sharing Access Criteria

Results

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Eye Diseases

Clinical Trials on Calcium alpha-ketoglutarate

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Slovakia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe