NAD+, a key coenzyme in human metabolism, has its precursor supplements NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) dubbed the "Hollywood anti-aging remedy." Lauded for their anti-aging effects, they have become "age-reversing essentials" for European and American celebrities—Hailey Bieber (wife of Justin Bieber) and the Kardashian family, among others, rely on them to maintain a youthful state.
However, shortly before the 618 Shopping Festival this year, NMN was suddenly banned from sale by customs on grounds of "exaggerated advertising and lack of legal status in China." People were left wondering whether to trust this supplement once hailed as the "fountain of youth"—could the widely promoted "NAD+ supplementation for anti-aging" be just a business marketing tactic?
Not long ago, two top anti-aging experts held a 2-hour-plus discussion on "whether NAD+ anti-aging works."
One is Andrew Huberman, an anti-aging specialist from Stanford University, who focuses on neuroscience and has made significant contributions to brain development, function, and neuroplasticity. His anti-aging podcast consistently ranks first among global health podcasts, beloved by audiences worldwide. His daily anti-aging methods also went viral online recently.
The other is Peter Attia, Stanford MD and exclusive doctor to Hugh Jackman (who played "Wolverine" in X-Men). He is a global expert in behavioral approaches, nutritional interventions, supplements, and pharmacological techniques. His book Outlive: The Science and Art of Longevity has long topped bestseller lists in Europe and America.
So, how do these two "top-tier" international experts evaluate the "top-tier" player in the anti-aging field (NAD+ supplements)?
PART 01 Is NAD+ Just a "Smart Tax"?
First, why did the idea of "NAD+ supplementation for anti-aging" emerge in the first place?
NAD+ (nicotinamide adenine dinucleotide), a crucial coenzyme in the human body, exists in almost every cell and is involved in various physiological processes such as energy metabolism and DNA repair.
As we age, NAD+ levels in the body gradually decline. Dr. Attia noted that a 2015 study showed blood NAD+ levels decrease by 10%–20% over approximately 40 years.
At first glance, "reversing aging by supplementing NAD+" seems reasonable. However, Dr. Attia offered a different perspective: while NAD+ levels do drop with aging, and supplementation does bring certain benefits, there is no research proving it extends lifespan—and exceeding a certain level can be fatal!
He explained that 99% of NAD+ functions as an electron carrier, meaning it is not consumed but acts as a "transporter" of electrons. Only a small portion of NAD+ is used by the longevity gene Sirtuins for DNA repair. Furthermore, intracellular NAD+ levels are tightly regulated—similar to how glucose is strictly controlled by insulin and adrenaline in the body.
"We, as organisms, cannot survive outside a specific pH range (scored 0–14). If NAD+ levels fall below 7 or exceed 7.8, we will die."
Regarding the claim that "NAD+ supplements have anti-inflammatory effects," Dr. Huberman said he believes in NAD+’s anti-inflammatory benefits—which is why he has been taking NMN.
However, Dr. Attia debunked this claim by citing two studies:
- A study on NR’s effect on fatty liver: 100 people with fatty liver were divided into two groups—one taking a regular dose of NR, the other a double dose. There were no differences in fat content, inflammatory markers, weight, or blood glucose between the two groups. However, if participants had initial liver fat content below 27%, low-dose NR reduced it from 20% to 15%.
- A study on NMN’s effect on glucose handling: In two groups (with and without insulin injection), the NMN group showed a slight increase in glucose handling after insulin treatment.
While these results are statistically significant, do they matter to patients? It’s equivalent to giving a diabetic a drug that lowers blood glucose by a few milligrams—essentially useless.
Did the expensive NAD+ supplements purchased earlier all go to waste?
Don’t be upset yet. Although the two experts questioned some claims about NAD+ supplements, they also shared potential benefits of NAD+ supplementation.
Dr. Huberman himself has been taking NMN, trying both pills and infusions. "For me, the most obvious effects are faster hair and nail growth, and more energy. I usually take it first thing in the morning."
Dr. Attia added that NAD+ supplementation may also reduce the risk of skin cancer. "A study showed that after taking NMN or NR, the incidence of basal cell carcinoma and squamous cell carcinoma (two common skin cancers linked to prolonged sun exposure) decreased by 60%–80%."
As for why it reduces skin cancer risk? Dr. Attia speculated it may be related to the rate of NAD+ decline in the skin—he mentioned at the start of the podcast that among all tissues, the skin has the fastest declining NAD+ levels.
While NAD+ supplements are not the so-called "anti-aging miracle drugs," they still offer health benefits—provided they are not taken blindly. This is why professional testing and scientifically reasonable dosing are essential before taking supplements; otherwise, they may do more harm than good.
PART 02 The Critical "Prime" for Anti-Aging
Neither expert is particularly young—both are around 50. It’s well-known that humans experience "steep aging" at 40, 55, and 60, so scientific and effective maintenance at this age is crucial!
Dr. Attia said the 50–70 age range is most critical. After 50, aging progresses: sleep quality declines, energy levels drop, and the body becomes less resilient.
During this period, it’s essential to build physiological reserves by focusing on diet, sleep, and exercise.
At 51, Dr. Attia has a muscular physique like a professional athlete. He places great emphasis on exercise, viewing it as one of the few tools that can extend lifespan and delay aging. "Building muscle in your 70s is extremely difficult. My vertical jump is now only half of what it used to be. At my age, if I stop exercising for a few months, I have to put in twice or three times the effort to regain my previous muscle mass."
Dr. Huberman also maintains a fitness routine: he does resistance training three times a week, walks in a weighted vest, and goes hiking. He mentioned taking a biological age test that predicted his life expectancy at 95, along with a vitality chart for different age groups.
Looking at his vitality chart, he reflected that he paid little attention to his health in his 20s and 30s, focusing solely on work. So he decided to start tracking his physical condition at 40 and adjust his anti-aging plan based on changes—hoping to remain "youthful" even at 80.
PART 03 Anti-Aging "Secrets" Shared by Experts
During the show, Dr. Huberman summarized several anti-aging methods:
- Exercise appropriately and regularly to maintain nerve-muscle connections, prevent falls, and pay attention to diet.
- Regulate mTOR: From infancy to adolescence, mTOR in cells increases rapidly, which benefits the growth of body tissues and organs. However, in middle and old age, excessive mTOR accelerates cellular senescence. Thus, anti-aging methods like calorie restriction and rapamycin intake reduce excess insulin and blood glucose to lower mTOR activity, preventing cells from entering a senescent state.
- NAD+ supplementation: At least some believe it has potential for lifespan extension.
- Extreme practices: For example, avoiding eating after 11 a.m.
Dr. Attia offered another perspective, stating that longevity methods fall into three categories:
- Non-negotiable daily activities: Eating, sleeping, and moving. The only choice is how to do them—either in ways that promote health or harm it.
- Disease-specific medications: Drugs like metformin, SGLT2 inhibitors, PCSK9 inhibitors, statins, or benazepril to delay chronic diseases such as cardiovascular and cerebrovascular diseases, cancer, and neurodegenerative diseases.
- Anti-aging drugs: Such as rapamycin, which combats aging phenotypes like inflammation, senescent cells, and reduced mTOR nutrient-sensing ability.
Dr. Attia mentioned in the podcast that to date, the only two interventions shown to extend lifespan in mice and small primates are rapamycin and calorie restriction. He himself takes rapamycin, though he occasionally experiences side effects like mouth ulcers.
Emotional health and well-being are also crucial—if you’re not happy, nothing else matters.
PART 04 Dr. Attia’s and Dr. Huberman’s Supplement Lists
Finally, here is a summary of the supplements the two doctors mentioned in the show—products they have tried extensively and continue to take:
Peter Attia’s Daily Supplements
- Ω-3 fish oil (EPA and DHA)
- Vitamin D
- Folic acid (B9) and Vitamin B12
- Magnesium (magnesium L-threonate, slow-release magnesium, magnesium oxide)
- Ashwagandha
- Creatine monohydrate
- LMNT sugar-free electrolytes
- Curcumin extract
- Pendulum probiotics
- Polyphenols
- AG1 (Note: This supplement is sponsored by the show—use your judgment rationally.)
Medications
- PCSK9 inhibitors, bempedoic acid, SGLT2 inhibitors, rapamycin
Andrew Huberman’s Daily Supplements
- AG1: Taken daily to support gut health
- Fish oil: >1g EPA
- Vitamin D: Approximately 125 mcg (5000 IU) daily
- Vitamin B12
- NMN and NR
- Tongkat Ali extract
- Green tea extract
- Magnesium
- Chamomile extract and L-theanine
- Protein powder
The two doctors reminded that supplements only play a "supplementary" role. The truly important factors are daily habits like sleep, diet, and exercise—these are the foundations of longevity.
It's okay. Go to bed early and make more money when you have time. Life is never confusing.