The energy problem starts in the cell: NAD+, mitochondria, and why you run out of steam

The cellular energy system is a factory, not a tank

Most people think of energy as something you store and spend. A tank that fills at night and empties through the day. That model is wrong in a way that matters for how you fix the problem.

Cellular energy is a production system, not a storage system. Your mitochondria are continuously manufacturing ATP from glucose and fat. The “running out of energy” experience is not an empty tank. It is a factory running below capacity. The machinery is aging. The raw materials (NAD+, CoQ10, oxygen delivery) are less abundant. Output drops.

Understanding this matters because the interventions that address a storage problem are different from the interventions that address a production problem. More sleep fixes the tank metaphor. Resistance training, Zone 2 cardio, and NAD+ precursors fix the factory metaphor.

NAD+ and why it matters

NAD+ is not a supplement. It is a molecule that every cell in your body requires to convert food into ATP. It is the electron carrier that sits at the center of the metabolic machinery. Without adequate NAD+, mitochondrial ATP production slows. With less ATP, cells have less energy for every function they perform.

NAD+ also activates sirtuins, the family of proteins that regulate DNA repair, inflammation, and mitochondrial biogenesis. Sirt1, activated by NAD+, is the closest thing to a longevity master switch that the current science has identified. This is why the NAD+ research got so much longevity attention: raising NAD+ does not just produce more energy, it activates repair pathways.

The problem: NAD+ declines approximately 50 percent between age 40 and age 60, and cannot be supplemented directly (oral NAD+ does not reach cells). NAD+ precursors, NMN and NR, are converted to NAD+ in cells and do raise blood NAD+ levels in published human studies. A 2022 study in Nature Aging (Yoshino et al.) found that NMN supplementation raised NAD+ levels in muscle tissue and improved some markers of insulin sensitivity in overweight, postmenopausal women. Other human trials with NR have shown similar NAD+ elevation.

The honest summary: the mechanism is real, the blood NAD+ elevation is real, the translation to meaningful human health and longevity outcomes is not yet fully established. Animal data is impressive. Human data is early but promising. The longevity influencer version (“NMN reversed aging in mice therefore it will make you younger”) is ahead of the evidence. The honest version is: NAD+ precursors are a reasonable longevity bet in the $50 to $80/month cost range for adults over 45 who have the sleep, exercise, and lab deficiency pieces in order.

CoQ10 and statins

Coenzyme Q10 sits at the end of the mitochondrial electron transport chain, directly involved in converting the electron gradient into ATP. Like NAD+, it declines with age. Statins (atorvastatin, rosuvastatin, simvastatin) reduce CoQ10 levels by blocking the mevalonate pathway, the same pathway that produces cholesterol. If you are on a statin and feel more fatigued than you expect to, low CoQ10 is a mechanistically plausible reason.

The clinical evidence that CoQ10 supplementation resolves statin-associated muscle symptoms (myalgia) is mixed; some studies show benefit, but the most recent meta-analyses are equivocal. But the mechanistic case for supplementing CoQ10 on a statin is solid enough that many cardiologists recommend it as a low-risk adjunct. Anyone on a statin experiencing fatigue or muscle discomfort has a reasonable basis to try CoQ10 (100 to 200 mg/day in ubiquinol form, which has better absorption than ubiquinone) for 8 to 12 weeks and assess.

The Livium recipe

Tool. Zone 2 cardio training and resistance training (covered in EF-01) are the foundation. They produce mitochondrial biogenesis through PGC-1 alpha activation, the same pathway that NAD+ and sirtuins regulate, arrived at from the exercise direction. For NAD+ support: Thorne Nicotinamide Riboside (NR) is the most clinically studied form. For statin users and adults over 55: NOW Foods CoQ10 200 mg (Ubiquinone) or a ubiquinol form for slightly better absorption. NOW Foods Alpha Lipoic Acid 100 mg is a mitochondrial antioxidant that recycles both CoQ10 and glutathione in the mitochondrial membrane.

Behavior. The mitochondrial biogenesis signal from exercise requires adequate intensity. Zone 2 cardio (the pace where you can hold a conversation but not easily) for 45 to 60 minutes, three or more times per week, produces sustained PGC-1 alpha activation. Interval training sessions (one or two per week) produce a sharper AMPK signal that complements the Zone 2 base. Both are needed for the full mitochondrial adaptation. NR or NMN supplements are best taken in the morning; there is weak evidence that evening dosing may interfere with circadian NAD+ rhythms that normally fall at night.

Threshold. Mitochondrial adaptations to regular exercise are measurable at 8 to 12 weeks: improved lactate threshold, better fat oxidation efficiency, and less perceived effort at a given work rate. These translate experientially to: easier mornings, less mid-afternoon energy drop, and faster recovery from physical effort. The NMN/NR contribution to this is harder to measure without a bloodwork panel. Run a NAD+ level through Function Health at baseline and at 12 weeks if you want a number.

Source: Livium editorial synthesis based on NIA Exercise and Healthy Aging and Yoshino et al., Nature Aging (2022) NMN RCT.

Plan of action

• Before adding NAD+ precursors, build the exercise foundation. Zone 2 cardio three times per week and resistance training twice per week produce the mitochondrial biogenesis signal that NMN/NR supplements are trying to augment. Supplementing without exercise is building on sand. Exercise first for eight weeks; add NMN or NR only after the base is established.
• If you are on a statin and experiencing fatigue or muscle discomfort, add CoQ10 100 to 200 mg/day before discussing medication changes. NOW Foods CoQ10 200 mg is the standard starting dose. Assess at 8 weeks. If symptoms persist, bring the CoQ10 supplementation to your cardiologist and discuss whether a different statin or dosing schedule is appropriate.
• Check your NAD+ level and related markers (homocysteine, methylation markers) through Function Health. NAD+ testing is available as an add-on panel and gives you a baseline. Spending $80/month on NMN without knowing your baseline NAD+ is an uncontrolled experiment.
• If you do add an NAD+ precursor: Thorne NR (Nicotinamide Riboside) is the most clinically studied form. Take it in the morning. The standard dose used in human trials is 250 to 300 mg/day.