LONGEVITY & CELLULAR HEALTH / FAQ
The Questions People Actually Type
Answers taken from the published record, with the uncomfortable parts left in.
What is NAD supplement used for?
In practice, NAD+ supplements are sold for energy, metabolic health and general anti-ageing, and are almost always precursors rather than NAD+ itself — usually nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR). What they have actually been tested on in humans is narrower. Trials have measured blood NAD+ concentration, walking distance and quality-of-life scores in middle-aged adults [2], and muscle insulin sensitivity in prediabetic, postmenopausal women [3]. Blood NAD+ rises dependably in these studies [2][5]. The 2025 Nature Metabolism review of the whole human evidence base concluded that efficacy in humans has so far been limited and that tissue-level data remain sparse [1], which is a fair summary of the distance between what the products are sold for and what has been shown.
What is the downside of taking NAD+?
Several, and they differ by form. Plain oral NAD+ is poorly taken into cells intact, so many researchers regard capsules of the coenzyme itself as largely ineffective compared with precursors. Beyond that, the largest downside is the evidence gap: raising blood NAD+ is well demonstrated [2][5], while translation to hard outcomes such as longevity or disease prevention in humans is unproven [1], and much of the most impressive data comes from rodents. Intravenous NAD+ can cause chest or abdominal discomfort, flushing and nausea when infused too quickly, and compounded injectable NAD+ has been subject to an FDA Class I recall for elevated bacterial endotoxin. A theoretical oncology concern also exists, since NAD+ supports proliferating cells and its role in cancer is context-dependent. Finally, supplement-grade material varies in purity and actual content, and third-party testing is not guaranteed.
Is it safe to take NAD daily?
That is a question for a clinician who knows an individual's history, and this desk does not answer it. What the literature can say is what the trials observed. Nicotinamide riboside at 100-1000 mg per day for eight weeks in healthy overweight adults produced no significant difference in adverse events from placebo, no flushing, no LDL elevation and no disruption of one-carbon metabolism [5]. Oral NMN at 300-900 mg per day for 60 days reported no safety issues at any dose in a multicentre trial [2]. Both studies were short, both enrolled specific populations, and neither was designed to detect rare or long-term harms. Absence of adverse findings in an eight-week trial is not the same thing as demonstrated long-term safety, and injectable and intravenous forms fall outside those data entirely.
Does NAD cause weight gain?
Nothing in the human trial record suggests it does, though weight change has not been a primary endpoint in the studies gathered here. The ten-week trial of oral NMN in prediabetic, postmenopausal women improved muscle insulin sensitivity while reporting no change in body composition and no change in HbA1c [3]. The 60-day multicentre NMN trial reported improved walking distance and quality-of-life scores and no safety issues at any dose, and its biological-age measure did not increase [2]. The honest answer is that these compounds are studied as metabolic maintenance rather than as weight interventions in either direction, and a reader looking for a weight effect will not find one established in this literature.
What does the MOTS-c peptide do?
MOTS-c is a sixteen-amino-acid peptide encoded inside the mitochondrial genome, in a reading frame within the 12S ribosomal RNA gene. Its best-characterised action is to inhibit the folate cycle and de novo purine biosynthesis, which raises AICAR and activates AMP-activated protein kinase (AMPK), improving glucose handling and insulin sensitivity primarily in skeletal muscle [10]. Under metabolic stress it also translocates from the mitochondrion into the nucleus and regulates nuclear gene expression in an AMPK-dependent manner, including antioxidant-response genes reached through NRF2 [12]. A 2024 study identified casein kinase 2 as a direct binding target, modulated in a tissue-specific way [8]. Exercise induces the body's own MOTS-c in muscle and circulation [11]. All of this describes what the peptide does in cells and animals; there are no human interventional trials.
What are the negative side effects of MOTS-c?
There is no human side-effect profile for MOTS-c, because no human efficacy or safety trials have been completed. That absence is the answer, and it is a more serious one than a list of mild effects would be. No published human pharmacokinetic study exists either — no measured half-life, bioavailability or dose-response — so the rodent doses in the literature, in the range of 0.5-15 mg/kg per day, cannot be scaled to people. The material sold is a research chemical whose purity, identity and sterility are not regulated as pharmaceuticals are. There is also evidence that effects are not uniform across populations: a pro-diabetogenic mitochondrial DNA variant affecting MOTS-c and ancestry-dependent exercise responses both point that way. Anything presented as a MOTS-c side-effect profile has been assembled from somewhere other than the clinical record.
Is MOTS-c legal to buy?
MOTS-c is not approved by the FDA for any human use and has no approved indication, formulation or dosing. It is sold only as a research chemical for laboratory use, and it is not for human consumption. That is a different legal situation from an approved medicine and a different one again from a dietary supplement — it is material sold for laboratory work, outside pharmaceutical quality regulation, where what is in a vial is not guaranteed by any regulator. Separately, elite sport prohibits it: anti-doping authorities classify MOTS-c among the peptide and metabolic-modulator agents banned at all times, and athletes who use it face sanctions. This site does not sell anything and does not advise on acquisition.
How often do you inject MOTS-c?
No injection schedule for people exists in the published literature, and this desk will not supply one. There is no approved human dosing for MOTS-c, no registered formulation, and no published human pharmacokinetic study establishing a half-life or dose-response from which a schedule could even be derived. What the animal literature contains, recorded here as description rather than instruction, is a range of roughly 0.5-15 mg/kg per day administered to rodents in published experiments — figures that do not translate to human use. Any protocol circulating in community discussion is anecdotal, not clinical evidence, and is not derived from a human trial because no such trial has been run.
What is epitalon?
Epitalon, also written Epithalon or the AEDG peptide, is a synthetic tetrapeptide — four amino acids, alanine-glutamate-aspartate-glycine. It was designed to reproduce the amino-acid composition of epithalamin, an extract of the bovine pineal gland, the structure that governs melatonin release and helps set circadian rhythm [13]. It is not the same substance as that extract, and conflating the two is a common error in material written about it. Research interest centres on two proposed actions: upregulation of hTERT and telomerase activity, associated with telomere elongation in cultured human cells [16], and stimulation of the melatonin-synthesis enzyme AANAT in pineal cells [15]. Epitalon has no approval as a medicine in the United States, the European Union or the United Kingdom, and is classified as a research chemical [13].
What are the benefits of epitalon according to research?
The research findings, stated precisely, are these. In telomerase-negative human fetal fibroblasts, the peptide induced expression of the catalytic telomerase subunit, telomerase activity and telomere elongation [16]. A 2025 study found dose-dependent telomere lengthening at 0.1-1 µg/mL in normal human cells through hTERT upregulation — and, in breast-cancer cell lines, lengthening through Alternative Lengthening of Telomeres instead [14]. In rat pinealocyte culture it stimulated AANAT and pCREB and raised melatonin in the culture medium [15]. A 2025 review characterises it as a geroprotective peptide with antioxidant, neuroprotective and antimutagenic properties, while noting that it remains uncertain whether the described mechanisms are the only ones and that structural characterisation is limited [13]. The one substantial human result — a six-to-eight-year study of 266 elderly people reporting a 1.6-1.8-fold mortality decrease with epithalamin alone and a 4.1-fold decrease with a thymalin combination — was observational, with no randomization and no placebo arm [17]. Those are laboratory and observational findings, not demonstrated human benefits.
What is the recommended dosage of epitalon in research protocols?
There is no recommended dosage, and this desk publishes none. Epitalon has no approved human indication, no registered formulation and no published human pharmacokinetic study — the short half-life often quoted for it is an inference from small-peptide chemistry rather than a measured value [13]. Without pharmacokinetics there is no scientific basis on which a human protocol could be constructed, which is why the published literature does not contain one. The concentrations that appear in the research record are cell-culture concentrations, not doses: the 2025 telomere study worked at 0.1-1 µg/mL in cultured human cells [14]. Numbers circulating in community protocols are anecdotal, not clinical evidence, and have no trial behind them.
How often should epitalon be cycled, once or twice a year?
No published human trial has established a cycling schedule for synthetic Epitalon, so the question has no evidence-based answer and this desk does not offer a preference. The nearest thing in the literature is the observational cohort, in which the pineal extract epithalamin was administered annually over six years alongside thymalin, and was associated with a reported 4.1-fold decrease in mortality against untreated controls — a study without randomization or a placebo arm, using the extract rather than the synthetic tetrapeptide [17]. That annual pattern is a description of what an uncontrolled study did, not a schedule derived from evidence. Cycling advice circulating in longevity communities is anecdotal, not clinical evidence, and readers should recognise it as convention rather than as a finding.