Biohacker Bryan Johnson, 48, has worked to stave off death with an extreme protocol<\/a> that includes five sessions of hyperbaric oxygen therapy a week, shockwave therapy<\/a> thrice weekly and an 18-hour fasting schedule.<\/p>\n Besides frustrating changes to their hormones, muscle mass and skin, quadragenarians like Kardashian and Johnson also have to worry about a drop in their nicotinamide adenine dinucleotide (NAD\u207a) levels.<\/p>\n Found in all living cells, the molecule plays a key role in cellular energy production, mitochondrial function, DNA repair and metabolism.<\/p>\n \u201cNAD\u207a levels naturally decline with age, most significantly in the 40s, [contributing to] chronic inflammation, poor sleep, metabolic disease and prolonged stress,\u201d Dr. Pooja Gidwani<\/a>, a double board-certified internal and obesity medicine physician based in LA, told The Post.<\/p>\n That\u2019s why Kardashian<\/a> and Johnson<\/a> have turned to nicotinamide mononucleotide (NMN) oral supplements<\/a> to boost their NAD\u207a levels.<\/p>\n Here\u2019s how NMN works in the body \u2014 and why it\u2019s often better than NAD\u207a supplementation<\/a>.<\/p>\n What is NMN?<\/p>\n NMN is a form of vitamin B3 that\u2019s absorbed rapidly in the gut and converted into NAD\u207a while inside cells.<\/p>\n By supporting NAD\u207a levels, NMN may improve mitochondrial energy production, insulin sensitivity, muscle function and vascular health.<\/p>\n \u201cClinically, any benefits tend to show up as improved energy regulation, exercise tolerance or metabolic markers rather than dramatic cosmetic or weight-loss effects,\u201d Gidwani said.<\/p>\n How do you start NMN supplementation?<\/p>\n NAD\u207a levels can be measured with specialized blood tests.<\/p>\n An NMN dose often ranges from 250 to 500 milligrams, Gidwani said, perhaps even going up to 1,000 mg. How and when you take the supplement is important.<\/p>\n \u201cNMN is typically taken in the morning, as increasing cellular energy later in the day may interfere with sleep for some individuals,\u201d Gidwani explained.<\/p>\n \u201cNMN appears to be most effective when used alongside foundational lifestyle factors, including adequate sleep, regular physical activity, sufficient protein intake and overall metabolic health optimization.\u201d<\/p>\n It tends to be most useful for older adults or metabolically stressed people who are already making these lifestyle changes, Gidwani said.<\/p>\n She noted that the most meaningful benefits of NMN are generally gradual and cumulative, developing over weeks to months of consistent supplementation.<\/p>\n Are there any downsides to NMN supplements?<\/p>\n \u201cShort-term human studies<\/a> suggest NMN is generally well-tolerated, but long-term safety data are still limited,\u201d Gidwani said.<\/p>\n \u201cReported side effects are usually mild and may include gastrointestinal discomfort, headaches or sleep disturbances, particularly at higher doses or when taken later in the day.\u201d<\/p>\n One potential issue is that NMN products vary widely in purity, potency and stability, which is why third-party testing and reputable sourcing are key.<\/p>\n The Food and Drug Administration does not regulate supplements the same way it regulates prescription drugs.<\/p>\n And NMN is not for everyone.<\/p>\n It should be used cautiously or avoided altogether by people being treated for cancer and pregnant or breastfeeding women.<\/p>\n \u201cIndividuals with complex medical conditions or those on multiple medications should discuss NMN use with a physician before starting supplementation,\u201d Gidwani said.<\/p>\n How does NMN compare to NAD\u207a supplementation?<\/p>\n \u201cNMN, as a precursor, is smaller, more bioavailable and readily converted inside cells into NAD\u207a, making it a more effective oral approach,\u201d Gidwani noted.<\/p>\n NAD\u207a, in contrast, is a large molecule that cannot directly penetrate cell membranes. That\u2019s why it\u2019s typically administered via IV infusion<\/a> or injection to bypass the digestive system.<\/p>\n Patients often experience intense, immediate effects from an NAD\u207a IV, while NMN users may notice subtle changes within hours, such as improved mental clarity or energy, particularly\u00a0if baseline NAD\u207a levels are low.<\/p>\n Still, taking an NMN capsule or powder is \u201cfar more practical\u201d for long-term use, Gidwani said.<\/p>\n \u201cNAD\u207a IV therapy is expensive, time-consuming and often associated with side effects such as nausea, flushing, chest tightness or anxiety during infusion,\u201d she continued.<\/p>\n \u201cFrom a cost, convenience and adherence perspective, NMN is generally a more accessible option.\u201d<\/p>\n Before you stock up on NMN \u2026<\/p>\n Gidwani emphasized that NMN \u201cmay help optimize cellular energy pathways in the right context,\u201d but it\u2019s \u201cnot a miracle anti-aging drug,\u201d nor can it replace sleep, exercise, nutrition or medical care. <\/p>\n \u201cThe goal of NMN supplementation is not to \u2018supercharge\u2019 the system, but to support normal cellular processes that become less efficient over time,\u201d she said.<\/p>\n \t\t\t\t\t\t\t\t![\"A](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/eccentric-billionaire-obsessed-living-forever-21751978.jpg\")
Biohacker Bryan Johnson is trying literally everything to not die. He\u2019s shown here getting a laser treatment to his face. Instagram\/@bryanjohnson_<\/p>\n![\"A](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/nicotinamide-mononucleotide-powder-used-support-119826900.jpg\")
<\/a>Nicotinamide mononucleotide is a form of vitamin B3 that\u2019s absorbed rapidly in the gut and converted into nicotinamide adenine dinucleotide while inside cells. Cloudy Design \u2013 stock.adobe.com<\/p>\n![\"Illustration](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/119826447.jpg\")
NAD\u207a is crucial for converting food into energy, repairing damaged DNA and regulating cell survival. designua \u2013 stock.adobe.com<\/p>\n