When people talk about ageing and hormones, the conversation usually jumps straight to menopause or “Low T.” Both are real and well-documented — testosterone in men declines by roughly 1% a year starting around age 30, and menopause brings its own well-studied hormonal shifts. But newer research is pointing to something upstream of both: a decline in cellular energy capacity that may help explain why hormone production slows in the first place, and why its effects show up in seemingly unrelated places, from libido to skin texture to hair thickness.
The molecule in question, once again, is NAD+, and the story here is a useful case study in how to read early-stage science without over-promising what it can do.
The Mechanistic Case: Plausible, Not Proven
Hormone production is metabolically expensive. The cells responsible for making testosterone — Leydig cells in the testes — rely heavily on mitochondrial energy output and on a NAD+-dependent enzyme, SIRT1, to function efficiently. Some research has found that SIRT1 supports the uptake of cholesterol (the raw material for testosterone) and helps maintain healthy Leydig cell function through cellular “clean-up” processes. In animal studies, boosting NAD+ availability has improved SIRT1 activity and testosterone output.
That’s a genuinely interesting mechanism. It is not, however, the same as proof that taking an NAD+ supplement will raise a person’s testosterone. Reviews of the current evidence are clear that no human study has yet demonstrated a direct, reliable increase in testosterone from NAD+ supplementation alone. What exists instead is a set of indirect links: NAD+ supports the mitochondrial function, insulin sensitivity, and sleep quality that all independently correlate with healthier hormone levels.
NAD+ therapy is not a substitute for hormone replacement therapy, and anyone considering either should be doing so under medical guidance rather than choosing between them based on marketing claims. Check out some good information on naddirect.com if you are ready to try it.
Why This Shows Up Beyond the Bedroom
The same cellular pathway that affects hormone production also touches two areas people rarely connect to it: cognitive clarity and skin or hair health.
NAD+ is essential for neuronal function, and the neurons involved in regulating desire and arousal are no exception. Brain fog and low mood — both linked to declining NAD+ availability with age — can independently dampen libido regardless of what’s happening with hormone levels themselves. In that sense, some of the sexual health benefits people report from NAD+-focused routines may run through improved mental clarity and mood as much as through any direct hormonal effect.
Skin and hair tell a related story. Skin cell turnover and collagen production are energy-intensive processes that depend on the same DNA repair enzymes — PARPs — that compete with sirtuins for the body’s limited NAD+ supply. As NAD+ declines, cells have less capacity for both jobs at once, which may partly explain why skin repair and hair regeneration both slow with age alongside declining hormone levels. It’s the same underlying cellular economy showing up in different tissues.
What Actually Helps, and What to Be Skeptical Of
Given how early and mixed the direct evidence is, it’s worth separating what’s reasonably well supported from what’s still speculative:
Reasonably well supported:
- Sleep, exercise, and stress management measurably support both NAD+ metabolism and hormonal balance, independent of any supplement.
- Getting actual hormone levels tested is far more informative than guessing based on symptoms, since fatigue, low libido, and mood changes overlap across many unrelated conditions.
- NAD+-supportive habits (consistent sleep, regular movement, moderate alcohol intake) plausibly support the broader biology that hormone production depends on.
Still speculative:
- Claims that NAD+ supplementation directly and reliably raises testosterone or estrogen in humans.
- The idea that NAD+ products can substitute for medically supervised hormone therapy where that’s clinically indicated.
A More Honest Way to Think About It
The most useful takeaway from this research isn’t “take NAD+ for your hormones.” It’s that hormonal ageing, sexual health, cognitive sharpness, and even skin and hair condition are more interconnected at the cellular level than most people assume — and that connection runs partly through NAD+ metabolism. Companies operating in this space, including NADdirect, now offer both diagnostic testing and NAD+-support products aimed at this broader picture rather than any single symptom, which reflects where the science is genuinely heading: toward treating these as connected systems rather than isolated complaints.
If any of this resonates with symptoms you’ve noticed, the most useful first move is still a conversation with a doctor and, where appropriate, actual bloodwork — not because the cellular biology isn’t real, but because knowing your own numbers is a far better foundation for any decision than a plausible mechanism on its own.
