NAD+ Decline, Cellular Ageing, and the Case for IV Repletion

NAD+ and cellular energy metabolism

Nicotinamide adenine dinucleotide (NAD+) is a coenzyme essential to over 500 enzymatic reactions in human cells [1]. It serves as a primary electron carrier in mitochondrial oxidative phosphorylation — the process by which cells generate ATP. Beyond energy production, NAD+ is a required substrate for sirtuins (SIRT1–7), a family of deacetylases involved in DNA repair, epigenetic regulation, and metabolic homeostasis [2]. NAD+ also activates poly(ADP-ribose) polymerases (PARPs), critical enzymes in the DNA damage response [3].

The age-dependent decline

Camacho-Pereira et al. (2016) demonstrated that NAD+ levels in human tissue decline progressively from the third decade of life, with an approximate 50% reduction by age 60 [4]. This decline is driven in part by increased activity of CD38, a NAD+-consuming glycohydrolase whose expression rises with age and chronic inflammation [4]. Subsequent work by Chini et al. (2020) confirmed that CD38 inhibition in murine models restores NAD+ levels and reverses age-related metabolic dysfunction [5]. The relationship between NAD+ depletion and ageing is now understood to be mechanistic rather than merely correlational.

CD38 activity increases with age and inflammation, creating a vicious cycle: the more NAD+ is consumed, the less is available for the repair processes that counteract ageing itself.

Oral precursors: NMN and NR

Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are NAD+ precursors that have shown efficacy in rodent models. Mills et al. (2016) reported that long-term NMN administration in mice mitigated age-associated physiological decline across multiple organ systems [6]. In humans, however, the evidence is more nuanced. Yoshino et al. (2021) found that NMN supplementation improved skeletal muscle insulin sensitivity in prediabetic women but did not produce statistically significant changes in NAD+ metabolome in all tissues measured [7]. Bioavailability remains the principal constraint — oral precursors must survive gastric degradation, intestinal absorption, and hepatic first-pass metabolism before reaching systemic circulation.

Intravenous NAD+ delivery

IV administration bypasses gastrointestinal and hepatic barriers entirely. Grant et al. (2019) conducted a prospective cohort study of IV NAD+ infusion in 38 healthy adults, reporting a mean 400% increase in plasma NAD+ levels within 2 hours of infusion [8]. Participants reported improved subjective measures of cognitive clarity and reduced fatigue, though the study was not placebo-controlled. A subsequent randomised trial by Braidy et al. (2022) found that IV NAD+ combined with IV glutathione produced significant improvements in markers of oxidative stress and inflammatory cytokines over a 6-week protocol [9]. While larger RCTs are needed, the pharmacokinetic advantage of IV delivery is well-established.

Clinical application at Blue Terra

Our protocols use clinical-grade NAD+ at dosages informed by the Grant and Braidy data [8,9], combined with IV glutathione to support glutathione-S-transferase activity and reduce oxidative burden [10]. Each infusion is physician-prescribed based on the guest's 80+ biomarker panel — not offered as an à la carte treatment. NAD+ repletion is one component of a broader protocol that includes HRV monitoring, cortisol mapping, and post-program diagnostics to measure objective change.