NAD+ for Energy and Healthy Ageing: What the Science Says

The energy crisis of ageing

If you've noticed that your energy isn't what it used to be — that afternoon slumps hit harder, recovery takes longer, and your get-up-and-go has got up and gone — you're not imagining it. At a cellular level, ageing genuinely depletes your energy reserves.

The culprit? A progressive decline in NAD+ (nicotinamide adenine dinucleotide), the molecule your mitochondria depend on to generate ATP — your body's universal energy currency. Research published in Nature Aging (2024) confirmed that NAD+ levels can fall by 50% or more between ages 40 and 60, with corresponding declines in mitochondrial efficiency.

This isn't just about feeling tired. Reduced cellular energy affects virtually every organ system — from your brain and muscles to your immune system and skin. Understanding this decline is the first step towards addressing it.

NAD+ and mitochondrial function

Mitochondria are often called the "powerhouses" of your cells — and NAD+ is their essential fuel. Here's the process in simple terms:

1. You eat food containing carbohydrates, fats, and proteins
2. These macronutrients are broken down into smaller molecules (glucose, fatty acids, amino acids)
3. Inside the mitochondria, NAD+ acts as an electron carrier in the citric acid cycle and electron transport chain
4. This process produces ATP — the energy that powers everything from muscle contractions to brain function

When NAD+ levels decline, this entire chain becomes less efficient. Your mitochondria produce less ATP per unit of fuel, generate more damaging reactive oxygen species (free radicals), and may even start to malfunction. This is one reason why researchers believe restoring NAD+ levels could improve energy production at its most fundamental level.

Animal studies have been remarkably consistent: boosting NAD+ improves mitochondrial function, increases exercise endurance, and promotes the creation of new, healthy mitochondria (a process called mitochondrial biogenesis).

Sirtuins: the longevity enzymes

NAD+ doesn't just power your mitochondria — it also activates a remarkable family of proteins called sirtuins. There are seven sirtuins in mammals (SIRT1 through SIRT7), and they've been dubbed "longevity enzymes" because of their wide-ranging roles in:

• DNA repair: SIRT1 and SIRT6 help maintain genomic stability
• Inflammation control: SIRT1 suppresses NF-κB, a master regulator of inflammatory responses
• Fat metabolism: SIRT1 and SIRT3 regulate fat oxidation and mitochondrial fatty acid metabolism
• Stress resistance: Sirtuins help cells survive under stress — mimicking some benefits of calorie restriction
• Circadian rhythm: SIRT1 helps regulate your body clock, which affects sleep quality and metabolic health

The key insight is that sirtuins are completely dependent on NAD+ to function. No NAD+ means no sirtuin activity. This is why researchers believe age-related NAD+ decline has such far-reaching consequences — it simultaneously impairs energy production AND the cellular maintenance systems that keep us healthy.

DNA repair and cellular resilience

Your DNA sustains thousands of "hits" every day — from UV radiation, environmental toxins, normal metabolic processes, and even the act of breathing. Fortunately, your cells have sophisticated repair mechanisms. The problem? These repair enzymes (called PARPs) also require NAD+ to function.

As you age, two things happen simultaneously: DNA damage accumulates faster, AND NAD+ levels decline — meaning your repair machinery has less fuel at the exact moment it's needed most. This creates a vicious cycle that accelerates cellular ageing.

Research from Harvard Medical School (published in Science) demonstrated that restoring NAD+ levels in ageing mice reversed markers of DNA damage and improved cellular function to resemble that of younger animals. While human replication is still pending, the mechanistic pathway is well understood.

Brain health and cognitive function

Your brain is the most energy-hungry organ in your body, consuming roughly 20% of your total energy despite being only 2% of your body weight. This makes it particularly vulnerable to NAD+ decline.

Preclinical studies have shown that boosting NAD+ may:

• Improve synaptic plasticity (the basis of learning and memory)
• Reduce neuroinflammation
• Protect against oxidative damage in brain cells
• Support the blood-brain barrier integrity

A particularly interesting finding: in a study published in Cell Metabolism, NAD+ precursor supplementation improved newly diagnosed Parkinson's disease patients' NAD+ metabolome — one of the first pieces of evidence that NAD+ replenishment has measurable effects in the human brain.

The latest research (2025–2026)

The NAD+ field is moving fast. Here are the most significant recent developments:

• Nature Metabolism (2025): A comprehensive systematic review confirmed that NR supplementation increases NAD+ levels in aged human skeletal muscle and induces anti-inflammatory transcriptomic signatures — the strongest human evidence to date for tissue-level effects
• Science Direct (2025): A meta-analysis of NAD+ precursor trials highlighted that while target engagement (raising NAD+ levels) is consistently achieved, functional outcomes remain heterogeneous — reinforcing the need for larger, longer trials
• NPR investigation (May 2026): Reported that IV NAD+ infusions may be less efficient at cellular uptake than previously assumed, potentially favouring subcutaneous injection or oral precursor approaches. This is relevant because our NAD+ injection pen uses subcutaneous delivery rather than IV infusion
• AHA Circulation (2025): The American Heart Association published a scientific statement calling for systematic comparison of different NAD+ precursors (NR vs NMN vs direct NAD+) — acknowledging the field's potential while highlighting evidence gaps

NAD+ therapy at The London Weight Loss Clinic

We offer NAD+ as part of our comprehensive approach to patient wellness. Our NAD+ injection pen provides a convenient at-home option that avoids the time and cost of IV drip clinic visits.

NAD+ therapy pairs naturally with our core weight loss services:

• Mounjaro (tirzepatide) — our most popular GLP-1 treatment
• Wegovy (semaglutide) — another highly effective GLP-1 option
• GLP-1 Nutritional Support Range — high-protein supplements designed for patients eating less on treatment
• Health coaching — personalised behaviour change support

We always present the evidence honestly. NAD+ therapy is promising but still an emerging field. We recommend it as a complement to evidence-based treatments, not as a standalone solution.