Eye DiseasesEarly Phase 1OAK AGENCT07269704
Effect of Nutritional Supplement Alpha-ketoglutarate for Age-related Ocular Disease
A Early Phase 1 study testing Calcium alpha-ketoglutarate in people with Eye Diseases, run by Stanford University at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Eye Diseases
- What is being tested?
- Calcium alpha-ketoglutarate
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 17 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Aug 2023to 10 Jun 2025
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Able and willing to give written informed consent
- Able to attend all study visits and complete the study procedures
- 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).
Who cannot join
- Diabetes and/or thyroid, liver, kidney, bowel, and metabolic diseases or disorders
- History of supplement allergy or planned major surgery
- Received any other clinical trial drug within 4 months
- Calculated creatinine clearance of less than 30 ml/min
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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:
- Determine how the eye absorbs supplements taken orally.
- Look for specific signs in the proteins and substances in the eyes of people with eye diseases who are also taking nutritional supplements.
- Conditions
- Eye Diseases
- Being tested
- Calcium alpha-ketoglutarate
- Medical subject headings
- Eye Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Calcium alpha-ketoglutarateDrug
Also called Prohealth Longevity
Participants took 2 g/day of calcium alpha-ketoglutarate orally, twice daily, for 7 days.
| Study group | Role | What they receive |
|---|---|---|
| Calcium alpha-ketoglutarate (Ca-aKG) | Experimental | 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. Receives: Drug: Calcium alpha-ketoglutarate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean change in aqueous humor aKG level
To evaluate the mean difference in fold-change in aKG levels from baseline to post-supplementation in eye fluid
Measured: Baseline and post-supplementation, approximately 28 days
Secondary outcomes (1)
Mean fold-change in metabolic and retinal pathways
To calculate mean fold-change in retinal metabolic and protein pathways from baseline to post-supplementation in eye fluid
Measured: Baseline and post-supplementation, approximately 28 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Dec 2025
- Study start15 Aug 2023
- Primary completion10 Jun 2025
- Study completion10 Jun 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Eye DiseasesStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 17 participants (actual)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Vinit Mahajan, Stanford University
- Investigators
- Vinit Mahajan, MD, PhD, Principal investigator, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07269704
- Sponsor's protocol ID
- 68157
- Acronym
- OAK AGE
- Status last verified
- Oct 2025
- First submitted
- 25 Nov 2025
- Last updated
- 3 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Age, sex, BMI, Medical history, ocular history
Publications
Filip RS, Pierzynowski SG, Lindegard B, Wernerman J, Haratym-Maj A, Podgurniak M. Alpha-ketoglutarate decreases serum levels of C-terminal cross-linking telopeptide of type I collagen (CTX) in postmenopausal women with osteopenia: six-month study. Int J Vitam Nutr Res. 2007 Mar;77(2):89-97. doi: 10.1024/0300-9831.77.2.89.
PubMed 17896582Riedel E, Nundel M, Hampl H. alpha-Ketoglutarate application in hemodialysis patients improves amino acid metabolism. Nephron. 1996;74(2):261-5. doi: 10.1159/000189319.
PubMed 8893139Wert KJ, Velez G, Kanchustambham VL, Shankar V, Evans LP, Sengillo JD, Zare RN, Bassuk AG, Tsang SH, Mahajan VB. Metabolite therapy guided by liquid biopsy proteomics delays retinal neurodegeneration. EBioMedicine. 2020 Feb;52:102636. doi: 10.1016/j.ebiom.2020.102636. Epub 2020 Feb 3.
PubMed 32028070Hou XW, Wang Y, Pan CW. Metabolomics in Age-Related Macular Degeneration: A Systematic Review. Invest Ophthalmol Vis Sci. 2020 Dec 1;61(14):13. doi: 10.1167/iovs.61.14.13.
PubMed 33315052
Study at a glance
From the registry record, last updated by the sponsor on 3 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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)
- ClinicalTrials.gov ID
- NCT07269704
- Acronym / sponsor ID
- OAK AGE / 68157
- Conditions
- Eye Diseases
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 17 participants (actual)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Study start
- 15 Aug 2023 (actual)
- Primary completion
- 10 Jun 2025 (actual)
- Study completion
- 10 Jun 2025 (actual)
- First posted
- 8 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aims of the study are as follows:
- Determine how the eye absorbs supplements taken orally.
- Look for specific signs in the proteins and substances in the eyes of people with eye diseases who are also taking nutritional supplements.
Study design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Calcium alpha-ketoglutarate (Ca-aKG) | Experimental | Drug: Calcium alpha-ketoglutarateAt 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Able and willing to give written informed consent
- Able to attend all study visits and complete the study procedures
- 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).
Key exclusion criteria (4 listed)
- Diabetes and/or thyroid, liver, kidney, bowel, and metabolic diseases or disorders
- History of supplement allergy or planned major surgery
- Received any other clinical trial drug within 4 months
- Calculated creatinine clearance of less than 30 ml/min
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Calcium alpha-ketoglutarateAlso: Prohealth LongevityParticipants took 2 g/day of calcium alpha-ketoglutarate orally, twice daily, for 7 days. | Drug | Calcium alpha-ketoglutarate (Ca-aKG) |
Primary outcome
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
1 secondary outcome
Mean fold-change in metabolic and retinal pathways
Time frame: Baseline and post-supplementation, approximately 28 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Apr 2026.
- Background: PubMed 17896582Filip RS, Pierzynowski SG, Lindegard B, Wernerman J, Haratym-Maj A, Podgurniak M. Alpha-ketoglutarate decreases serum levels of C-terminal cross-linking telopeptide of type I collagen (CTX) in postmenopausal women with osteopenia: six-month study. Int J Vitam Nutr Res. 2007 Mar;77(2):89-97. doi: 10.1024/0300-9831.77.2.89.
- Background: PubMed 8893139Riedel E, Nundel M, Hampl H. alpha-Ketoglutarate application in hemodialysis patients improves amino acid metabolism. Nephron. 1996;74(2):261-5. doi: 10.1159/000189319.
- Background: PubMed 32028070Wert KJ, Velez G, Kanchustambham VL, Shankar V, Evans LP, Sengillo JD, Zare RN, Bassuk AG, Tsang SH, Mahajan VB. Metabolite therapy guided by liquid biopsy proteomics delays retinal neurodegeneration. EBioMedicine. 2020 Feb;52:102636. doi: 10.1016/j.ebiom.2020.102636. Epub 2020 Feb 3.
- Background: PubMed 33315052Hou XW, Wang Y, Pan CW. Metabolomics in Age-Related Macular Degeneration: A Systematic Review. Invest Ophthalmol Vis Sci. 2020 Dec 1;61(14):13. doi: 10.1167/iovs.61.14.13.
- Individual participant dataSharing planned: Yes. Age, sex, BMI, Medical history, ocular history
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Vinit Mahajan, MD, PhD principal investigator
Stanford University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Calcium alpha-ketoglutarate in people with Eye Diseases, run by Stanford University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean change in aqueous humor aKG level (time frame: Baseline and post-supplementation, approximately 28 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07269704, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Apr 2026.