Why does energy drop in your 30s and 40s? And can NAD+ help?

The energy decline many women experience in their 30s and 40s has a cellular explanation: NAD+ levels, which power mitochondrial energy production in every cell, begin declining measurably from the mid-30s onward.† Research published in Nutrients via the National Institutes of Health documents that NAD+ bioavailability declines during normal aging, with high cellular NAD+ levels associated with metabolic and mitochondrial health. Supplementing with a NAD+ precursor such as nicotinamide riboside (NR) supports healthy NAD+ levels, which in turn supports cellular energy production and cognitive function.† Always consult your healthcare provider before starting any new supplement.

What is actually happening to your energy in your 30s and 40s

The fatigue women describe in their mid-30s and 40s is often dismissed as stress, poor sleep, or lifestyle factors. Those factors are real contributors, but the cellular story runs deeper. Mitochondria, the structures in every cell responsible for converting nutrients into usable energy, rely on NAD+ as a required cofactor in the electron transport chain, the core biochemical process of energy production. As NAD+ levels decline, mitochondrial efficiency declines with them. Cells produce less ATP. Energy output decreases. The feeling is real because the cellular mechanism is real.†

The cognitive dimension follows the same logic. The brain is the most energy-demanding organ in the body, consuming approximately 20 percent of total energy output despite representing only about 2 percent of body weight, according to the National Institute of Neurological Disorders and Stroke. When cellular energy production becomes less efficient, the brain is among the first systems to register the effect.†

"The midlife transition has really been forgotten historically in women's healthcare."

— Jessica Nazzaro, DO, FACOG, NCMP, Board-Certified OB-GYN and National Certified Menopause Practitioner

What the research says about NAD+ and energy in women

The clinical evidence on NR supplementation in humans consistently shows that it raises NAD+ metabolites in blood and tissue. The landmark Nature Communications trial found that chronic NR supplementation was well-tolerated and significantly elevated NAD+ levels in healthy middle-aged and older adults. Separately, research published in Nutrients reviewed NAD+ modulation strategies and found that increased NAD+ production is associated with beneficial metabolic and mitochondrial outcomes in aging.†

The direct connection between NR supplementation and subjective energy improvement in women specifically is still being characterized in clinical research. What is established is the mechanistic pathway: NR raises NAD+, NAD+ supports mitochondrial energy production, and mitochondrial energy production is the cellular foundation of the energy women feel day to day.†

NAD+ and brain fog: the cellular energy connection

Brain fog is not a clinical diagnosis, but the women who experience it describe it consistently: difficulty concentrating, slower recall, mental fatigue that does not resolve with sleep. The cellular energy explanation for brain fog in women over 35 centers on the same NAD+ decline that drives physical fatigue. When brain cells have less NAD+ available, their energy production becomes less efficient, and the high-demand cognitive tasks that previously felt effortless begin to require more effort.†

Creatine addresses brain energy through the phosphocreatine-ATP system, which is a complementary but distinct mechanism from NAD+. For women whose brain fog has both components, pairing our NAD+ supplement with 500 mg clinically studied NR with our micronized creatine with just one ingredient addresses both cellular energy pathways.† For more on the creatine side of this equation, read: can creatine support brain function in women?

Other reasons energy declines for women in this decade

NAD+ decline is one piece of a larger picture. Women in their 30s and 40s are also navigating the early hormonal shifts of perimenopause, which can begin in the early 40s or even late 30s for some women. Sleep disruption, changes in cortisol patterns, and declining progesterone all contribute to the fatigue and cognitive symptoms of this life stage. NAD+ supplementation addresses the cellular energy layer.† It does not replace strategies that address sleep, stress, and nutritional foundations.

For women who want to address nutrient density alongside cellular energy, our beef organ supplement formulated specifically for women supplies naturally occurring iron, B-vitamins, and CoQ10, nutrients that support the same mitochondrial energy systems that NAD+ relies on.†

"I know what it means to run on empty. Pink Stork NAD+ exists because women deserve to understand what is happening in their cells, and to have a clean, science-backed tool to support it."

— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

How to use NAD+ for energy support

Take one capsule of NAD+, a cellular energy support formula for women over 30, daily in the morning with or without food. Consistency matters more than timing. NR supplementation begins elevating circulating NAD+ metabolites within a few weeks of consistent daily use, with the Nature Communications trial showing significant elevation within that window.

NAD+ supplementation during pregnancy and breastfeeding has not been established as safe by current research. Women who are pregnant, breastfeeding, or trying to conceive should consult their healthcare provider before use.

For the full NAD+ category guide, read: what is the best NAD+ supplement for women?

Frequently asked questions

At what age should women start taking NAD+?

NAD+ decline begins measurably in the mid-30s. Women who are experiencing fatigue, brain fog, or declining energy in their 30s have a reasonable basis for considering NAD+ supplementation. There is no single correct age to start. The decision is best made in conversation with a healthcare provider who can assess individual circumstances.

Will NAD+ give me energy like caffeine does?

No. NAD+ works through a different mechanism than stimulants. Caffeine produces an acute stimulant effect by blocking adenosine receptors. NAD+ supports the cellular energy production infrastructure over time.† The effect is felt as more sustained and stable energy rather than the spike-and-crash pattern associated with caffeine. It typically takes several weeks of consistent use to notice the difference.

Can NAD+ help with fatigue from disrupted sleep?

Research on creatine has found that it supports cognitive performance under sleep deprivation, a finding with a clear cellular energy mechanism. NAD+ supports mitochondrial energy production more broadly.† Whether NAD+ specifically mitigates the cognitive effects of poor sleep has not been directly studied, but supporting the cellular energy foundation is a reasonable strategy for women whose sleep quality is compromised by perimenopause or other factors.†

Is the energy drop in your 30s and 40s permanent?

NAD+ decline is a normal part of aging, but it is not irreversible at the cellular level. Supplementation with NR has been shown to raise NAD+ metabolites in healthy adults. Lifestyle factors including exercise, quality sleep, and adequate nutrition also support NAD+ metabolism. The goal is not to reverse aging but to support the cellular systems that healthy aging depends on.†

Can NAD+ help with perimenopause fatigue specifically?

Yes. Perimenopause is one of the life stages where NAD+ support is most relevant, as the hormonal shifts of this transition place additional demand on cellular energy systems at exactly the point when NAD+ levels are already declining naturally.† For a dedicated breakdown, read: can NAD+ support energy during perimenopause?

† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.