A Phase 3 interventional study of Nicotinamide Riboside (NR) and Placebo in Peripheral Artery Disease (PAD), sponsored by Northwestern University. Not yet recruiting. Open to participants aged 50 Years and older. Per ClinicalTrials.gov, last updated 2026-08-24.
Sponsored by Northwestern University · Phase 3, Interventional, and Treatment
Among people with peripheral artery disease (PAD) age 50 and older, the investigators will test the hypothesis that PAD participants randomized to nicotinamide riboside (NR) will have greater improvement or less decline in six-minute walk distance at six-month follow-up, compared to those randomized to placebo. The study will randomize 250 participants with PAD age 50 and older to one of two groups for six months: nicotinamide riboside vs placebo. Our primary outcome is change in six-minute walk distance at six-month follow-up. Secondary outcomes are Walking Impairment Questionnaire (WIQ) distance score, PROMIS Mobility score, calf muscle perfusion (measured by magnetic resonance arterial spin labeling (MRI ASL)), oxidative stress (measured by plasma oxidized LDL), NAD+ abundance in whole blood, 6-minute walk improvement by baseline whole blood NAD+ levels, and 6-minute walk distance at 4 weeks after intervention completion.
To achieve the specific aims, the study will randomize 250 participants age 50 and older with PAD to one of two groups: nicotinamide riboside vs placebo. Participants will be followed for six months, with an additional four-week follow-up period after completion of the study intervention.
1,377 studies on the registry are indexed under Peripheral Arterial Disease; 275 are open to participants now.
This study's planned enrollment of 250 is above the median of 70 across 927 interventional studies indexed under Peripheral Arterial Disease.
Browse Peripheral Arterial Disease studies →Northwestern University is the lead sponsor of 1,423 studies on the registry; 198 are open to participants now.
Of its 105 completed or terminated interventional studies of FDA-regulated products, 78 (74%) have results posted.
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Exclusion Criteria:
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The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Nicotinamide Riboside (NR)
Drug: Placebo
The nicotinamide riboside intervention is manufactured by ChromaDex. Participants randomized to nicotinamide riboside will take two capsules twice daily. Each capsule contains 250 mg of nicotinamide riboside, for a total of 1000 mg of nicotinamide riboside per day.
The placebo is manufactured by ChromaDex and is visually identical to the nicotinamide riboside capsules. Participants randomized to placebo will take two capsules twice daily. The placebo will not contain any nicotinamide riboside.
Six-minute walk distance
Change in six-minute walk distance between baseline and 6-month follow-up.
Time frame: Baseline to 6-months
Walking Impairment Questionnaire (WIQ) distance score
Patient reported outcome measuring assessing participant perceived ability to walk distances. Scored on a 0-100 scale, 100-best.
Time frame: Baseline to 6-month follow-up
PROMIS Mobility score.
Patient reported outcome measure of mobility.
Time frame: Baseline to 6-month follow-up
Calf muscle perfusion
Calf muscle perfusion measured by magnetic resonance imaging (MRI) arterial spin labeling.
Time frame: Baseline to 6-month follow-up
Oxidative stress
Measured by plasma oxidized LDL.
Time frame: Baseline to 6-month follow-up
NAD+
NAD+ will be measured in whole blood
Time frame: Baseline to 6-month follow-up
6-minute walk
Distance walked in 6- minutes
Time frame: Baseline to four weeks after primary outcome measurement (i.e. 7-month follow-up)
Mitochondrial activity in gastrocnemius muscle
Mitochondrial oxygen consumption measured by respirometry using the Oroborus.
Time frame: Baseline to 6-month follow-up
Gastrocnemius muscle NAD+ abundance
NAD+ abundance measured in gastrocnemius muscle
Time frame: Baseline to 6-month follow-up
Gastrocnemius muscle sirtuin1 (SIRT1)
Gastrocnemius muscle biopsy measure of sirtuin1 (SIRT1).
Time frame: Baseline to 6-month follow-up
Gastrocnemius muscle phosphorylated endothelial nitric oxide synthase (eNOS)
Ratio of phosphorylated endothelial nitric oxide synthase (eNOS) to total eNOS in gastrocnemius muscle biopsies
Time frame: Baseline to 6-month follow-up
Calf muscle capillary density
Gastrocnemius muscle biopsy measures of capillary density
Time frame: Baseline to 6-month follow-up
Gastrocnemius muscle poly (ADP-ribose) polymerase (PARP) abundance
Western blot will be used to measure PARP in gastrocnemius muscle
Time frame: Baseline to 6-month follow-up
No study locations are listed for this record.
Start is estimated for Dec 2026; primary completion for Dec 2030, 48 months later.
Of 26 phase 3 interventional studies under Peripheral Arterial Disease, half reached primary completion within 51 months of starting (the median), counting those still running; a quarter within 37 and three quarters within 58. This study's planned 48 months is close to that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Nicotinamide-beta-riboside