The cosmetics industry sells products that work on the surface. NAD⁺ decline changes the skin from within. Here you can find out what actually happens in the skin cell, why creams are not enough, and what NMN achieves that no topical application can.
Women spend more on skin care than almost any other personal category. Serums, retinoids, vitamin C, collagen creams, peptide formulas. The industry generates hundreds of billions of dollars annually with one promise: the right product, applied in the right order, keeps skin looking as it once did. Some of it works. Most of it works at the margins. None of it touches the reason why skin began to change in the first place.
The changes most women notice in their 30s and 40s are not a surface problem. The loss of firmness, the altered texture, the way light falls differently on the face, the fine lines in places that seemed unchanged just a few years ago - these are all cellular problems.
The cells that produce collagen and elastin, thus keeping the skin firm and plump, produce less of them. They repair damage more slowly. And they renew themselves less efficiently. The reason is a decline in cellular energy supply that no cream can reach. NAD⁺ is the fuel for this supply, and NMN is what restores it.
What skin aging really is at the cellular level
Skin consists of several layers. The outermost is the epidermis. It constantly renews itself: in the basal layer, cells divide, slowly migrate upwards, mature, and are eventually shed.
Below that lies the dermis. This is where fibroblasts work – the cells that produce collagen, elastin, and hyaluronic acid.
The structural quality of the skin depends entirely on these fibroblasts: its firmness, its elasticity, its thickness, and its ability to retain moisture. Crucially, it depends on what the fibroblasts produce and how efficiently they repair themselves.
Fibroblast function declines with age. The most important reason for this is cellular energy. Fibroblasts are very active cells. Producing collagen is metabolically demanding. And maintaining the enzymatic machinery for DNA repair constantly requires energy.
When this energy supply declines – which it does because NAD⁺ levels decrease from the mid-20s – fibroblasts slow down. Collagen production decreases. DNA damage in skin cells accumulates faster than it is repaired. The skin begins to change, visibly from the outside, but originating entirely within the cell.
The collagen numbers and what they mean
From the mid-20s, collagen production decreases by about 1% per year. By the mid-40s, a woman has thus lost about 20% of the collagen she had at 25.
In the first five years after menopause, women lose up to 30% of their remaining skin collagen. The reason is the sharp drop in estrogen: estrogen directly signals fibroblasts to produce collagen. If it is lacking, this signal becomes significantly weaker.
Two decades of gradually declining cellular energy and then an abrupt hormonal upheaval – together, this leads to the visible acceleration of skin aging that many women notice in their late 40s and early 50s.
These numbers are not estimates. They come from research on skin biology and menopause. The annual 1% collagen decrease is documented in several studies. The acceleration after menopause is one of the most frequently reproduced findings in dermatological research.
What is less often discussed alongside these numbers is the cellular energy mechanism behind it. And therefore, the question of what it means for the progression of skin aging to address precisely this mechanism.
From the mid-20s, collagen production decreases by 1% per year. In the first five years after menopause, women lose an additional 30%.
Where NAD⁺ comes in with skin aging
NAD⁺ is required for the enzymatic processes that make the work of fibroblasts possible in the first place.
It activates PARP enzymes. These detect and repair DNA damage that accumulates in skin cells – due to cell division and UV radiation, environmental pollution, and oxidative stress. It supplies mitochondria, which generate the energy with which fibroblasts build collagen. And it activates sirtuins, which regulate the inflammatory response in skin tissue and control, via epigenetic signals, how actively skin cells renew themselves.
If enough NAD⁺ is present, skin cells repair efficiently. Fibroblasts produce collagen at a steady rate. Inflammatory processes in the tissue remain regulated. And the renewal cycle that keeps the epidermis fresh and responsive runs on schedule.
When NAD⁺ levels drop, all these processes slow down simultaneously. The skin does not suddenly fail. It builds up a deficit in several systems in parallel.
This is precisely why skin aging looks the way it does: as a gradual change on many levels at once, which no single active ingredient from the outside can fully counteract.
Why external collagen doesn't work – and how NMN functions differently
Collagen molecules are too large to pass through the skin barrier in relevant quantities. Most collagen creams therefore work on the surface. They can temporarily improve the appearance of the skin by forming a film on it. But they do not reach the dermis and do not reach the fibroblasts that actually produce structural collagen.
Ingested collagen has a different problem. During digestion, it is broken down into amino acids and distributed throughout the body wherever these amino acids are needed. The body does not preferentially direct them to the face or dermis. A supplement cannot dictate to the body where it uses the supplied material.
NMN works fundamentally differently. It does not provide the raw material for collagen. It can restore the cellular conditions under which fibroblasts produce collagen themselves - at the rate and quality they were capable of before their energy supply declined.
This is the crucial difference. NMN doesn't give the skin something it needs from the outside. It can give it back its own ability to do what it always could.
What to realistically expect – and when
Skin changes are not the first thing women notice with NMN. Sleep changes in the first one to two weeks. Energy stabilizes in weeks two to four. The skin follows from the second to third month.
This aligns with biology. Fibroblasts respond to improved energy supply over weeks. Collagen synthesis is a slow process. And the epidermal renewal cycle in younger women takes about 28 days and slows down with age.
Visible improvements in skin quality take longer with any measure that works at the cellular level than improvements in energy or sleep. However, they are usually more lasting because they reflect a real change in cell function and not a temporary effect.
What women describe who take NMN for three months or longer is not a dramatic overnight change. It's skin that looks different, without being able to pinpoint anything specific, because nothing has been changed externally. The texture improves. The light falls differently on the face. The skin feels different.
These are the signs of cells that have enough energy for their repair work. And that's exactly what NMN makes possible through the restoration of NAD⁺.
The skin reflects the condition of the cells beneath it. Most skincare products treat the reflection. NMN treats the cells. This difference is not a marketing statement. It is the difference between the surface of a problem and its cause.
Sources
- Brincat, M. P., Baron, Y. M., & Galea, R. (2005). Effect of menopause on the skin. Climacteric, 8(Suppl 1), 11–23. https://doi.org/10.1080/13697130500161963
- Shuster, S., Black, M. M., & McVitie, E. (1975). The influence of age and sex on skin thickness, skin collagen and density. British Journal of Dermatology, 93(6), 639–643. https://doi.org/10.1111/j.1365-2133.1975.tb05100.x
- Covarrubias, A. J., Perrone, R., Grozio, A., & Verdin, E. (2021). NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 22(2), 119–141. https://doi.org/10.1038/s41580-020-00313-x
- Yaku, K., Okabe, K., & Nakagawa, T. (2018). NAD metabolism: Implications in aging and longevity. Ageing Research Reviews, 47, 1–17. https://doi.org/10.1016/j.arr.2018.05.006
- Massudi, H., Grant, R., Braidy, N., et al. (2012). Age-associated changes in oxidative stress and NAD+ metabolism in human tissue. PLOS ONE, 7(7), e42357. https://doi.org/10.1371/journal.pone.0042357
- Yoshino, M., Yoshino, J., Kayser, B. D., et al. (2021). Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science, 372(6547), 1224–1229. https://doi.org/10.1126/science.abe9985