How Do Sirtuins Work?
Sirtuins are NAD+-dependent histone deacetylases that couple cellular energy status to gene expression, mitochondrial function and stem cell regulation. This page summarises the mechanism and the research models in which
Sirtuins (silent information regulator proteins, abbreviated SIRT) are a conserved family of nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases and ADP-ribosyltransferases. In the cosmetic and skin-biology literature they are grouped with the class of histone deacetylases (HDACs) whose targeted modulation regulates DNA repair and gene expression [1]. The family is conventionally divided by subcellular localisation, with SIRT1 and SIRT2 described as nuclear and cytoplasmic, SIRT3, SIRT4 and SIRT5 as mitochondrial, and SIRT6 and SIRT7 as nuclear. The evidence block used for this page does not supply a sequence, molecular formula or molecular weight for any sirtuin, so none is stated here.
The pathway the work centres on is the NAD+-dependent sirtuin axis: sirtuin catalytic activity consumes NAD+, which places the enzymes downstream of cellular energy status and upstream of mitochondrial biogenesis, oxidative metabolism and insulin sensitivity [2]. Sirtuins are also described as one arm of the broader nutrient-sensing network that includes mTOR, AMPK and insulin/IGF-1 signalling, a network reported to govern adult stem cell fate by modulating cellular metabolism [7].
Research Studies
Sirtuins and histone deacetylase targeting in skin biology
A review of molecular targets in cosmetic science identified histone deacetylases, and sirtuins in particular, among the major targets under investigation in skin biology, alongside telomerase, matrix metalloproteinases, antioxidant enzymes, CD44, tyrosinase, MITF and melanocortin receptors [1]. In that framing, sirtuins sit within the group of macromolecules reported to regulate DNA repair and gene expression in the context of skin ageing, pigmentation, inflammation and tissue regeneration [1]. This is a review-level statement of target relevance rather than a report of an intervention effect.
SIRT1 and SIRT3 in energy expenditure and insulin sensitivity
A registered trial protocol on sirtuin activators and weight loss describes the SIRT family, particularly SIRT1 and SIRT3, as a target of interest because of reported involvement in mitochondrial biogenesis, energy expenditure, oxidative metabolism and the regulation of insulin sensitivity [2]. The same protocol notes that long-term effectiveness of lifestyle-based weight-management strategies remains limited and frames sirtuin activation as a molecular pathway of interest in obesity, described there as a chronic, multifactorial disease [2]. The population in question is adults with obesity; the document is a trial record, not an outcome report.
Nicotinamide riboside, pterostilbene and muscle stem cells in elderly humans
A registered study in elderly human participants examined whether nicotinamide riboside (NR), an NAD+ precursor, and the polyphenol pterostilbene (PT) affect skeletal muscle regeneration [6]. The rationale given is that successful regeneration depends on a functional pool of satellite cells, which remain quiescent through adulthood and re-enter cycles of proliferation and self-renewal after muscle damage, and that ageing is associated with loss of that quiescence and impaired satellite cell function [6]. The protocol states that animal studies identified sirtuin activation as a common denominator for increasing satellite cell function and activity, and that NR and PT are natural stimulators of sirtuins [6]. The animal-only status of the mechanistic claim is explicit in the source.
Nicotinamide riboside and pterostilbene in amyotrophic lateral sclerosis
Two registered ALS trials describe a combination of NR and pterostilbene [4][5]. The stated rationale is that increased activity of histone deacetylation enzymes (sirtuins) together with increased access to NAD can delay disease progression, that NR can increase cellular access to NAD, and that pterostilbene stimulates sirtuins [4][5]. Both records describe ALS as a rapidly progressive disease of the nervous system with mean survival from diagnosis of roughly 2.5 to 3 years and no effective treatment apart from riluzole [4][5]. The population is patients with ALS; these are trial registrations, and no efficacy result is reported in the evidence supplied.
NAD+ availability as the upstream constraint on sirtuin activity
Because sirtuin catalysis consumes NAD+, the cofactor is treated as the rate-limiting input in this axis. A review of NAD+ in cardiovascular disease describes the molecule as an important redox cofactor with a major role in energy metabolism and discusses activation of the rate-limiting enzyme in NAD+ biosynthesis in that context [8]. The same review is a general overview of current understanding rather than a report of a trial in a defined population [8].
Sirtuins within nutrient-sensing networks in adult stem cells
A review of nutrient-sensing pathways in adult stem cells places sirtuins alongside mTOR, AMPK and insulin/IGF-1 signalling as central regulators of stem cell fate, acting by dynamically modulating cellular metabolism [7]. The framework proposed there integrates these pathways into a network that dictates metabolic transitions in adult stem cells across homeostasis, ageing and disease [7]. This is a conceptual synthesis; it does not report an intervention or a measured effect size.
Sirtuins and mitochondrial-derived peptides in vascular ageing
A review of mitochondrial-derived peptides as therapeutics and biomarkers for vascular ageing examines humanin, MOTS-c and small humanin-like peptides in the context of mitochondrial dysfunction, apoptosis, inflammation and oxidative stress in endothelial and vascular smooth muscle cells [3]. Sirtuins are not the primary subject of that review, but the mitochondrial quality-control territory it covers overlaps with the SIRT3–SIRT5 compartment described in the sirtuin literature [2][3]. Findings there are attributed to the vascular ageing field and are review-level.
Sirtuins in ovarian ageing and reproductive longevity
A review of mechanisms of ageing and longevity as they relate to ovarian function describes ovarian ageing as progressive follicular reserve depletion accompanied by mitochondrial dysfunction, oxidative stress and endocrine decline, and evaluates emerging strategies to preserve reproductive longevity [9]. Sirtuins appear within the set of mechanistic contributors considered in that review [9]. The claims are review-level and concern ovarian tissue, not skin or muscle.
Comparison of sirtuin-related research models
| Model or population | Intervention or focus | Evidence type |
|---|---|---|
| Elderly human participants | NR + pterostilbene, skeletal muscle regeneration and satellite cells [6] | Registered trial; animal-derived rationale stated [6] |
| Patients with ALS | NR + pterostilbene, disease progression [4][5] | Registered trials; no outcome reported in evidence [4][5] |
| Adults with obesity | SIRT1/SIRT3 activation, energy expenditure, insulin sensitivity [2] | Registered trial protocol [2] |
| Skin biology (review scope) | HDAC/sirtuin targeting in ageing, pigmentation, inflammation [1] | Review [1] |
| Adult stem cells (review scope) | Sirtuins within mTOR/AMPK/IGF-1 network [7] | Review [7] |
| Cardiovascular disease (review scope) | NAD+ as redox cofactor and biosynthetic rate-limiting enzyme [8] | Review [8] |
| Vascular ageing (review scope) | Mitochondrial-derived peptides, mitochondrial dysfunction [3] | Review [3] |
| Ovarian ageing (review scope) | Ageing and longevity mechanisms, follicular reserve [9] | Review [9] |
If you are reading this for personal health reasons
The materials described on this page are supplied for laboratory research use only, and we do not provide dosing, administration or medical guidance of any kind. Nothing here is a recommendation to take a compound, and no statement on this page should be read as a promise of an outcome in any person. Anyone considering a sirtuin-related compound for themselves should speak to a licensed clinician.
Sources
- [1] Molecular Targets in Modern Cosmetic Science — https://europepmc.org/article/PMC/PMC13567315
- [2] Sirtuin Activators and Weight Loss — https://clinicaltrials.gov/study/NCT07802548
- [3] Mitochondrial-Derived Peptides as Therapeutics and Biomarkers for Combating Vascular Aging and Associated Cardiovascular Diseases — https://europepmc.org/article/PMC/PMC12951053
- [4] A Trial of Nicotinamide/Pterostilbene Supplement in ALS: The NO-ALS Extension Study — https://clinicaltrials.gov/study/NCT05095571
- [5] The NO-ALS Study: A Trial of Nicotinamide/Pterostilbene Supplement in ALS — https://clinicaltrials.gov/study/NCT04562831
- [6] Effect of Nicotinamide Riboside and Pterostilbene Supplementation on Muscle Regeneration in Elderly Humans — https://clinicaltrials.gov/study/NCT03754842
- [7] Nutrient-sensing pathways in adult stem cells: Orchestrating homeostasis, aging, and disease — https://pubmed.ncbi.nlm.nih.gov/42546460/
- [8] Role of nicotinamide adenine dinucleotide in cardiovascular disease — https://pubmed.ncbi.nlm.nih.gov/42047243/
- [9] Mechanistic insights into aging and longevity: Implications for ovarian function and health — https://pubmed.ncbi.nlm.nih.gov/41833148/