Age: 18 - 70+
Healthy Volunteers: Not accepted
Inclusion Criteria:
1. Provision of signed and dated informed consent form.
2. Stated willingness to comply with all study procedures and availability for the planned 14-week duration of participation.
3. Adults aged 18 to 80 years (inclusive) at the time of consent, of any sex.
4. Unilateral symptomatic radiographic KOA defined as Kellgren-Lawrence (KL) grade 2 or 3 in the tibiofemoral joint of the index knee, as determined from a standing knee radiograph obtained within the prior 12 months or at Screening.
5. Knee pain in the index knee with a Visual Analogue Scale (VAS) score of 20-80 (on a 0-100 scale) over the prior 7 days at Screening.
6. No changes in OA-directed therapy (including analgesics, NSAIDs, topical therapies, or non-pharmacologic regimens) in the 3 months prior to Screening.
7. Agreement to refrain from vitamin B3-containing supplements (nicotinic acid, nicotinamide, nicotinamide riboside) and any multivitamin containing these ingredients for at least 14 days prior to Baseline and throughout the duration of the study.
8. Ability to take oral capsule medication and willingness to adhere to the prescribed NRPT regimen.
9. Agreement to adhere to lifestyle considerations specified in Section 5.3 throughout the study.
Exclusion Criteria:
1. Prior surgical intervention on the index knee (including arthroscopy, ligament reconstruction, osteotomy, or joint replacement).
2. Severe radiographic knee disease (KL grade 4) in the index knee.
3. Bilateral symptomatic radiographic KOA (i.e., KL grade ≥2 with symptomatic pain in both knees).
4. Diagnosis of inflammatory arthritis (including but not limited to rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, or crystal arthropathy of the index knee).
5. Use of systemic corticosteroids, intra-articular corticosteroid or hyaluronic acid injection in the index knee, chondroitin, glucosamine, or other polyphenol-containing supplements (including resveratrol, curcumin) within the 3 months prior to Screening.
6. Self-reported substantive change in physical activity level (initiation of a new exercise program or cessation of regular activity) within the 3 months prior to Screening.
7. Pregnancy, lactation, or planning pregnancy during the study period. Women of childbearing potential must have a negative serum or urine pregnancy test at Screening.
8. Severe or uncontrolled comorbid conditions that, in the opinion of the investigator, would compromise participant safety or interpretability of study data, including but not limited to: uncontrolled diabetes mellitus (HbA1c >9.0% or requiring recent insulin initiation); active cardiovascular disease (myocardial infarction, unstable angina, decompensated heart failure, or stroke within 6 months); severe chronic kidney disease (eGFR <30 mL/min/1.73 m²); active liver disease or AST/ALT >2.5× the upper limit of normal; active malignancy (other than non-melanoma skin cancer) within 5 years; or active substance use disorder.
9. Known allergy or hypersensitivity to nicotinamide riboside, pterostilbene, resveratrol, or any excipient of Basis®.
10. Concurrent participation in another interventional clinical trial or use of an investigational agent within 30 days prior to Screening.
11. Any other condition that, in the opinion of the investigator, would interfere with the participant's ability to comply with the protocol or with the safety or scientific integrity of the study.