Evidence verdict: Creatine has comparatively strong human evidence for supporting lean mass and strength in older adults, particularly alongside resistance training. Cognitive evidence is promising but substantially less certain, and there is no evidence that creatine extends human lifespan.
Evidence verdict: Nicotinamide riboside reliably raises NAD-related metabolites in humans and appears generally well tolerated over short-to-medium trials, but most clinical outcomes are inconsistent or null. Selected biomarker signals are interesting; evidence that NR slows aging or improves longevity remains unestablished.
Evidence verdict: Oral NMN increases NAD-related biomarkers in humans and has generally been well tolerated in short trials, but evidence that it improves clinically meaningful aging outcomes is mixed and insufficient to claim that NMN slows aging or extends human lifespan.