The Wild Science of Growing Younger (Worth)

Reversing aging isn’t just a crazy-billionaire fever dream. From the mundane to the revolutionary, many ways exist, or may exist, to soften aging and extend healthy lives.

There are a lot of hyperbolic and crazy-sounding theories and assertions in the vast movement to counteract the inexorable march from the quick to the dead. Xprize founder Dr. Peter Diamandis thinks we may one day upload our consciousness to the cloud. As such, the 62-year-old is doing everything he can to keep his body healthy in the meantime and maybe reach “longevity escape velocity”—continuing to extend his life long enough to take advantage of ever-more life-extending methods. His business partner—motivational speaker and entrepreneur Tony Robbins—says that stem cell injections he received in Panama (because it’s illegal in the U.S.) not only repaired a torn rotator cuff but rejuvenated his entire body. Half-billionaire Bryan Johnson reportedly spends about two million dollars a year on testing, taking more than 100 drugs and supplements, and—for a time—infusing his teenage son’s blood plasma. And they are not alone. Jeff Bezos, Yuri Milner, and other tech titans are reported to have together poured about $3 billion into Altos Labs, a startup promising to reprogram human cells to their youthful state.

But the most extreme theories and practices are a veneer over a vast body of laboratory and clinical research, and even DIY biohacking, indicating it may be possible to at least slow the aging process. Could most of us live to or beyond 120 years, considered the uppermost limit of human lifespan? Some advocates, including those with university research labs, think so. Others call it bunk.

Rejuvenation efforts also promise to brighten the twilight years by allowing people to live longer and be healthier and more vigorous. Picture 80-year-olds with the body of a 60-year-old. Proponents talk about not only extending lifespan but also what they call healthspan.

“It’s this biology of aging that makes us get Alzheimer’s or cancer or heart [disease] or diabetes,” says Dr. Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine. “Aging is the mother of those diseases…You deal with the mother, and you don’t have those kids.”

After speaking with a dozen experts or advocates, reading four books, parsing over 30 research papers, and absorbing popular press coverage—I know two things about the possibility of slowing or reversing aging. First, anyone can do a few cheap, simple things (like exercise) to improve their longevity prospects. Second, several new tactics, technologies, and tools might someday work.

It’s worth looking deeper at these ideas—but with a skeptical eye. That’s especially true because proponents and detractors may have a financial stake in the success or failure of new therapies. The quest for longevity is not just a matter of science but of money, personal philosophy, and personal rivalry.

Jump down this rabbit hole with me—tracing longevity science and speculation from the simple to the startling.

Full article: The Wild Science of Growing Younger | Worth


Quote in article from Nir Barzilai about supplements. I didn’t see any particulars mentioned but this is a clear risk for people who take a lot of supplements.

The extreme case for supplements is serial tech entrepreneur Bryan Johnson, who swallows dozens of pills. “When I look at each one of the supplements, I understand why he picked those,” says Barzilai. “In his mind, if he’s taking all of them together, they’ll be additive, or even synergistic…And he’s missing the fact that some of them are antagonistic to each other.”


I’m 72 and am regularly mistaken for being mid 50’s. Did it with lifelong exercise, weight training and portion control.


Peter Diamandis Embraces the Sci-Fi of Life Extension

Now in his 60s, the physician and entrepreneur is directing tens of millions of dollars at far-out tech to let him and others live twice as long, or longer.

My mind swings back and forth as I talk to Dr. Peter Diamandis, founder of the Xprize Foundation and one of the biggest boosters in the high-tech quest for life extension. One moment, he’s giving down-to-earth advice about building muscle and avoiding sugar. The next, he’s flirting with the idea of living inside machines.

How seriously does he take the latter topic? Can technology really let us live forever, I ask.

“That’s a fascinating question. And I try and avoid it as much as possible,” he says, before diving in. “I spend a lot of my time in the world of AI and exponential tech. So do I believe we’re going to be able to, at some point, upload the human mind into the cloud? I do.”

Diamandis isn’t the first person to espouse such ideas. And a lot of the grandest come from his relationship with futurists such as inventor and business partner Ray Kurzweil. What’s interesting, though, is the balancing act Diamandis strives to achieve between the commonsense and the fantastical, and how he’s built businesses across that spectrum.

Full story here:

More articles and videos on Longevity and Biotech from Worth:


I would certainly like a list of the ones that are antagonistic and a list of supplements that are synergistic. That would be a huge help.
And, yes, I read through this whole thread. I know of some conflicts… the one that comes to mind is don’t take taurine and glycine at the same time, and glucosamine and NAC may conflict.
And, of couse, you don’t want to be boosting mTOR and inhibiting it at the same time.


And what is worse… the purported benefits of these supplements are certainly not clinically proven and long term safety is a big unknown. I think people that take that many supplements should consider themselves lucky if they come out even.


Is that the advice that you would give to Bryan Johnson? He has a whole team of experts. The best that money can buy.

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I think Bryan Johnson is a separate case (and I think Nir Barzelai may be wrong in that respect, in calling him out on this). At least Bryan Johnson is constantly blood testing and tracking changes with a team of doctors, so if anything is going off the rails he’ll know pretty quickly.


It just seems like many doctors (because of medical school or a need to be conservative in their practice) find Bryan Johnson’s experiment somewhat offensive. In some ways it seems like they may be afraid that he will succeed and it will make all their warnings seem foolish.

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… “experts” just like Sinclair :rofl: I love how he managed to pawn off his useless Resveratrol patents for almost a billion, sucker born every minute.


Perhaps some doctors are in that group, but I think many other doctors are honestly concerned about people being potentially harmed (or wasting a ton of money). The simple truth that the vast majority of people (I would guess 98%+) using significant numbers of supplements probably are not doing significant blood testing and / or working closely with medical professionals to track outcomes and benefits in any systematic way, so at some point it could become an issue in terms of harm. And you do see these events periodically in the news, like this situation that was in the news this week: Man’s death from vitamin D overdose raises alarm over supplements

This guy’s high dosing of Vitamin D may have been easily identified by the doctors because it was a single supplement, but I can imagine scenarios where many times you’d have a person ill or dying from unique combinations of large numbers of supplements where the results may be less obvious.

See: Deeply disturbing information on combining longevity supplements


If you’re saying that there’s a lot of idiots out there, you’re preaching to the choir. But if you look at the people on this forum as the choir, I think that it clearly shows that you can pursue this course (albeit in a much more limited and cheaper way) intelligently and with reasonable safety (life doesn’t come without risk). Many of us are doing regular blood tests and other home health testing as well as watching the science and practicing a good lifestyle. To say that we’re being foolish for not doing everything under the watchful eye of the medical establishment, I think is wrong (at least for me).


The people active on this forum are a rather unique subset of the supplement (and longevity drug) users I think. Many (if not “most”) of us really research things in-depth, and do significant amounts of blood testing to track results. but for people just randomly taking lots of supplements that get good press in the daily news with no blood testing… I suspect that could have negative results for many (or certainly be a waste of money in many cases).


Exactly! That’s why I bristle when someone like @Dr.Bart comes here on the forum and says…

If he was saying that in Walmart…fine…more power to him. But this is not Walmart.


To illustrate the illusion of expert knowledge, let me present you with a case study of vitamin E supplementation . Back in the 90’s many experts including physicians, PhD’s and so on were “convinced” that Vitamin E supplementation was the anti-oxidant panacea to heart disease, cancer and other conditions. They were so convinced that they recommended supplementation to their patients on regular basis.
It took years and multiple huge studies later to show the actual truth. Vitamin E supplementation was not helpful and in fact proved to be harmful. Here is a quick summary.

Vitamin E and Health

Many claims have been made about vitamin E’s potential to promote health and prevent and treat disease. The mechanisms by which vitamin E might provide this protection include its function as an antioxidant and its roles in anti-inflammatory processes, inhibition of platelet aggregation, and immune enhancement.

A primary barrier to characterizing the roles of vitamin E in health is the lack of validated biomarkers for vitamin E intake and status to help relate intakes to valid predictors of clinical outcomes [6]. This section focuses on four diseases and disorders in which vitamin E might be involved: heart disease, cancer, eye disorders, and cognitive decline.

Coronary heart disease

Evidence that vitamin E could help prevent or delay coronary heart disease (CHD) comes from several sources. In vitro studies have found that the nutrient inhibits oxidation of low-density lipoprotein (LDL) cholesterol, thought to be a crucial initiating step for atherosclerosis [6]. Vitamin E might also help prevent the formation of blood clots that could lead to a heart attack or venous thromboembolism [17].

Several observational studies have associated lower rates of heart disease with higher vitamin E intakes. One study of approximately 90,000 nurses found that the incidence of heart disease was 30% to 40% lower in those with the highest intakes of vitamin E, primarily from supplements [18]. Among a group of 5,133 Finnish men and women followed for a mean of 14 years, higher vitamin E intakes from food were associated with decreased mortality from CHD [19].

However, randomized clinical trials cast doubt on the efficacy of vitamin E supplements to prevent CHD [20]. For example, the Heart Outcomes Prevention Evaluation (HOPE) study, which followed almost 10,000 patients at high risk of heart attack or stroke for 4.5 years [21], found that participants taking 400 IU/day of natural vitamin E (268 mg) experienced no fewer cardiovascular events or hospitalizations for heart failure or chest pain than participants taking a placebo. In the HOPE-TOO follow-up study, almost 4,000 of the original participants continued to take vitamin E or placebo for an additional 2.5 years [22]. HOPE-TOO found that vitamin E provided no significant protection against heart attacks, strokes, unstable angina, or deaths from cardiovascular disease or other causes after 7 years of treatment. Participants taking vitamin E, however, were 13% more likely to experience, and 21% more likely to be hospitalized for, heart failure, a statistically significant but unexpected finding not reported in other large studies.

The HOPE and HOPE-TOO trials provide compelling evidence that moderately high doses of vitamin E supplements do not reduce the risk of serious cardiovascular events among men and women >50 years of age with established heart disease or diabetes [23]. These findings are supported by evidence from the Women’s Angiographic Vitamin and Estrogen study, in which 423 postmenopausal women with some degree of coronary stenosis took supplements with 400 IU vitamin E (form not specified) and 500 mg vitamin C twice a day or placebo for >4 years [24]. Not only did the supplements provide no cardiovascular benefits, but all-cause mortality was significantly higher in the women taking the supplements.

The latest published clinical trial of vitamin E’s effects on the heart and blood vessels of women included almost 40,000 healthy women ≥45 years of age who were randomly assigned to receive either 600 IU of natural vitamin E (402 mg) on alternate days or placebo and who were followed for an average of 10 years [25]. The investigators found no significant differences in rates of overall cardiovascular events (combined nonfatal heart attacks, strokes, and cardiovascular deaths) or all-cause mortality between the groups. However, the study did find two positive and significant results for women taking vitamin E: they had a 24% reduction in cardiovascular death rates, and those ≥65 years of age had a 26% decrease in nonfatal heart attack and a 49% decrease in cardiovascular death rates.

The most recent published clinical trial of vitamin E and men’s cardiovascular health included almost 15,000 healthy physicians ≥50 years of age who were randomly assigned to receive 400 IU synthetic alpha-tocopherol (180 mg) every other day, 500 mg vitamin C daily, both vitamins, or placebo [26]. During a mean follow-up period of 8 years, intake of vitamin E (and/or vitamin C) had no effect on the incidence of major cardiovascular events, myocardial infarction, stroke, or cardiovascular morality. Furthermore, use of vitamin E was associated with a significantly increased risk of hemorrhagic stroke.

In general, clinical trials have not provided evidence that routine use of vitamin E supplements prevents cardiovascular disease or reduces its morbidity and mortality. However, participants in these studies have been largely middle-aged or elderly individuals with demonstrated heart disease or risk factors for heart disease. Some researchers have suggested that understanding the potential utility of vitamin E in preventing CHD might require longer studies in younger participants taking higher doses of the supplement [27]. Further research is needed to determine whether supplemental vitamin E has any protective value for younger, healthier people at no obvious risk of CHD.


Antioxidant nutrients like vitamin E protect cell constituents from the damaging effects of free radicals that, if unchecked, might contribute to cancer development [9]. Vitamin E might also block the formation of carcinogenic nitrosamines formed in the stomach from nitrites in foods and protect against cancer by enhancing immune function [28]. Unfortunately, human trials and surveys that have attempted to associate vitamin E intake with cancer incidence have found that vitamin E is not beneficial in most cases.

Both the HOPE-TOO Trial and Women’s Health Study evaluated whether vitamin E supplements might protect people from cancer. HOPE-TOO, which followed men and women ≥55 years of age with heart disease or diabetes for 7 years, found no significant differences in the number of new cancers or cancer deaths between individuals randomly assigned to take 400 IU/day of natural vitamin E (268 mg) or a placebo [22]. In the Women’s Health Study, in which healthy women ≥45 years of age received either 600 IU of natural vitamin E (402 mg) every other day or a placebo for 10 years, the supplement did not reduce the risk of developing any form of cancer [25].

Several studies have examined whether vitamin E intake and/or supplemental vitamin E affects the risk of developing prostate cancer. A prospective cohort study of >29,000 men found no association between dietary or supplemental vitamin E intake and prostate cancer risk [29]. However, among current smokers and men who had quit, vitamin E intakes of more than 400 IU/day (form not specified) were associated with a statistically significant 71% reduction in the risk of advanced prostate cancer. In a clinical trial involving 29,133 male smokers, men randomly assigned to take daily supplements of 111 IU of synthetic vitamin E (50 mg, as dl-alpha-tocopheryl acetate) for 5–8 years had 32% fewer prostate cancers compared to subjects who did not take the supplements [30]. Based in part on the promising results of this study, a large randomized clinical trial, called the SELECT trial, began in 2001 to determine whether 7–12 years of daily supplementation with 400 IU of synthetic vitamin E (180 mg, as dl-alpha-tocopheryl acetate), with or without selenium (200 mcg, as L-selenomethionine), reduced the number of new prostate cancers in 35,533 healthy men age 50 and older. The trial was discontinued in October 2008 when an analysis found that the supplements, taken alone or together for about 5.5 years, did not prevent prostate cancer [31]. Results from an additional 1.5 years of follow-up from this trial (during which the subjects no longer received vitamin E or selenium), showed that the men who had taken the vitamin E had a 17% increased risk of prostate cancer compared to men only taking placebos, a statistically significant difference [32]. The risk of developing prostate cancer was also slightly increased in subjects taking vitamin E plus selenium or selenium alone, but the differences were not statistically significant. No differences were found among groups in the incidence of lung or colorectal cancers or all cancers combined. Study staff members will continue to monitor participants’ health for up to 5 more years. The National Cancer Institute website provides additional information on the SELECT trialexternal link disclaimer.

One study of women in Iowa provides evidence that higher intakes of vitamin E from foods and supplements could decrease the risk of colon cancer, especially in women <65 years of age [33]. The overall relative risk for the highest quintile of intake (>35.7 IU/day, form not specified) compared to the lowest quintile (<5.7 IU/day, form not specified) was 0.32. However, prospective cohort studies of 87,998 women in the Nurses’ Health Study and 47,344 men in the Health Professionals Follow-up Study failed to replicate these results [34]. Although some research links higher intakes of vitamin E with decreased incidence of breast cancer, an examination of the impact of dietary factors, including vitamin E, on the incidence of postmenopausal breast cancer in >18,000 women found no benefit from the vitamin [35].

The American Cancer Society conducted an epidemiologic study examining the association between use of vitamin C and vitamin E supplements and bladder cancer mortality. Of the almost one million adults followed between 1982 and 1998, adults who took supplemental vitamin E for 10 years or longer had a reduced risk of death from bladder cancer [36]; vitamin C supplementation provided no protection.

Evidence to date is insufficient to support taking vitamin E to prevent cancer. In fact, daily use of large-dose vitamin E supplements (400 IU of synthetic vitamin E [180 mg]) may increase the risk of prostate cancer.

Eye disorders

Age-related macular degeneration (AMD) and cataracts are among the most common causes of significant vision loss in older people. Their etiologies are usually unknown, but the cumulative effects of oxidative stress have been postulated to play a role. If so, nutrients with antioxidant functions, such as vitamin E, could be used to prevent or treat these conditions.

Prospective cohort studies have found that people with relatively high dietary intakes of vitamin E (e.g., 20 mg/day [30 IU]) have an approximately 20% lower risk of developing AMD than people with low intakes (e.g., <10 mg/day [<15 IU]) [37,38]. However, two randomized controlled trials in which participants took supplements of vitamin E (500 IU/day [335 mg] d-alpha-tocopherol in one study [39] and 111 IU/day (50 mg) dl-alpha-tocopheryl acetate combined with 20 mg/day beta-carotene in the other [40]) or a placebo failed to show a protective effect for vitamin E on AMD. The Age-Related Eye Disease Study (AREDS), a large randomized clinical trial, found that participants at high risk of developing advanced AMD (i.e., those with intermediate AMD or those with advanced AMD in one eye) reduced their risk of developing advanced AMD by 25% by taking a daily supplement containing vitamin E (400 IU [180 mg] dl-alpha-tocopheryl acetate), beta-carotene (15 mg), vitamin C (500 mg), zinc (80 mg), and copper (2 mg) compared to participants taking a placebo over 5 years [41]. A follow-up AREDS2 study confirmed the value of this and similar supplement formulations in reducing the progression of AMD over a median follow-up period of 5 years [42].

Several observational studies have revealed a potential relationship between vitamin E supplements and the risk of cataract formation. One prospective cohort study found that lens clarity was superior in participants who took vitamin E supplements and those with higher blood levels of the vitamin [43]. In another study, long-term use of vitamin E supplements was associated with slower progression of age-related lens opacification [44]. However, in the AREDS trial, the use of a vitamin E-containing (as dl-alpha-tocopheryl acetate) formulation had no apparent effect on the development or progression of cataracts over an average of 6.3 years [45]. The AREDS2 study, which also tested formulations containing 400 IU (180 mg) vitamin E, confirmed these findings [46].

Overall, the available evidence is inconsistent with respect to whether vitamin E supplements, taken alone or in combination with other antioxidants, can reduce the risk of developing AMD or cataracts. However, the formulations of vitamin E, other antioxidants, zinc, and copper used in AREDS hold promise for slowing the progression of AMD in people at high risk of developing advanced AMD.

Cognitive decline

The brain has a high oxygen consumption rate and abundant polyunsaturated fatty acids in the neuronal cell membranes. Researchers hypothesize that if cumulative free-radical damage to neurons over time contributes to cognitive decline and neurodegenerative diseases, such as Alzheimer’s disease, then ingestion of sufficient or supplemental antioxidants (such as vitamin E) might provide some protection [47]. This hypothesis was supported by the results of a clinical trial in 341 patients with Alzheimer’s disease of moderate severity who were randomly assigned to receive a placebo, vitamin E (2,000 IU/day dl-alpha-tocopherol), a monoamine oxidase inhibitor (selegiline), or vitamin E and selegiline [47]. Over 2 years, treatment with vitamin E and selegiline, separately or together, significantly delayed functional deterioration and the need for institutionalization compared to placebo. However, participants taking vitamin E experienced significantly more falls.

Vitamin E consumption from foods or supplements was associated with less cognitive decline over 3 years in a prospective cohort study of elderly, free-living individuals age 65–102 years [48]. However, a clinical trial in primarily healthy older women who were randomly assigned to receive 600 IU (402 mg) d-alpha-tocopherol every other day or a placebo for ≤4 years found that the supplements provided no apparent cognitive benefits [49]. Another trial in which 769 men and women with mild cognitive impairment were randomly assigned to receive 2,000 IU/day vitamin E (form not specified), a cholinesterase inhibitor (donepezil), or placebo found no significant differences in the progression rate of Alzheimer’s disease between the vitamin E and placebo groups [50]

In summary, most research results do not support the use of vitamin E supplements by healthy or mildly impaired individuals to maintain cognitive performance or slow its decline with normal aging [51]. More research is needed to identify the role of vitamin E, if any, in the management of cognitive impairment [52].

Health Risks from Excessive Vitamin E

Research has not found any adverse effects from consuming vitamin E in food [6]. However, high doses of alpha-tocopherol supplements can cause hemorrhage and interrupt blood coagulation in animals, and in vitro data suggest that high doses inhibit platelet aggregation. Two clinical trials have found an increased risk of hemorrhagic stroke in participants taking alpha-tocopherol; one trial included Finnish male smokers who consumed 50 mg/day for an average of 6 years [53] and the other trial involved a large group of male physicians in the United States who consumed 400 IU (180 mg) of synthetic vitamin E every other day for 8 years [26]. Because the majority of physicians in the latter study were also taking aspirin, this finding could indicate that vitamin E has a tendency to cause bleeding.

The FNB has established ULs for vitamin E based on the potential for hemorrhagic effects (see Table 3). The ULs apply to all forms of supplemental alpha-tocopherol, including the eight stereoisomers present in synthetic vitamin E. Doses of up to 1,000 mg/day (1,500 IU/day of the natural form or 1,100 IU/day of the synthetic form) in adults appear to be safe, although the data are limited and based on small groups of people taking up to 3,200 mg/day of alpha-tocopherol for only a few weeks or months. Long-term intakes above the UL increase the risk of adverse health effects [6]. Vitamin E ULs for infants have not been established.

Table 3: Tolerable Upper Intake Levels (ULs) for Vitamin E [6] Age Male Female Pregnancy Lactation
1–3 years 200 mg 200 mg
4–8 years 300 mg 300 mg
9–13 years 600 mg 600 mg
14–18 years 800 mg 800 mg 800 mg 800 mg
19+ years 1,000 mg 1,000 mg 1,000 mg 1,000 mg

Two meta-analyses of randomized trials have also raised questions about the safety of large doses of vitamin E, including doses lower than the UL. These meta-analyses linked supplementation to small but statistically significant increases in all-cause mortality. One analysis found an increased risk of death at doses of 400 IU/day (form not specified), although the risk began to increase at 150 IU [54]. In the other analysis of studies of antioxidant supplements for disease prevention, the highest quality trials revealed that vitamin E, administered singly (dose range 10 IU–5,000 IU/day; mean 569 IU [form not specified]) or combined with up to four other antioxidants, significantly increased mortality risk [55].

The implications of these analyses for the potential adverse effects of high-dose vitamin E supplements are unclear [56-59]. Participants in the studies included in these analyses were typically middle-aged or older and had chronic diseases or related risk factors. These participants often consumed other supplements in addition to vitamin E. Some of the studies analyzed took place in developing countries in which nutritional deficiencies are common. A review of the subset of studies in which vitamin E supplements were given to healthy individuals for the primary prevention of chronic disease found no convincing evidence that the supplements increased mortality [60].

However, results from the recently published, large SELECT trial show that vitamin E supplements (400 IU/day [180 mg] as dl-alpha-tocopheryl acetate) may harm adult men in the general population by increasing their risk of prostate cancer [32]. Follow-up studies are assessing whether the cancer risk was associated with baseline blood levels of vitamin E and selenium prior to supplementation as well as whether changes in one or more genes might increase a man’s risk of developing prostate cancer while taking vitamin E.

This is just one supplement. So for someone to proclaim that their 100+ supplement stack is effective and safe because they did their “research” is a combination of hubris and foolishness. Animal studies mean nothing. Observational studies mean nothing. Show me a 1000+, multi-center, long term RCT - then we can talk.


Again, when you start preaching, you should take into account who you are preaching to. All of that long winded post is old hat here. Show me a post here that recommends taking Vitamin E. I haven’t seen one (not saying that one isn’t buried here somewhere).
And I’m not taking 100+ supplements…if you want to argue that case, take it up with Bryan Johnson.

I never said you did, in fact my original comment had nothing to do with you and you are the one that brought up Bryan Johnson. Not sure why are you so triggered ? Maybe you need some Ashwagandha in your stack.


I have no issues with doctors, PHDs and researchers coming on here and sharing their knowledge, in fact I think its a huge help. I appreciate the knowledge and reminders. I find that for me its easy to get too optimistic about the latest, greatest new research and get enthusiastic about trying things.

Sometimes I get busy and don’t do my blood testing as much as I think I should, etc. - or have missed some research that shows a new variable to watch for or new test to check occasionally.

I try to be open to knowledge wherever it comes from - and I appreciate the participation of medical experts here; the people who have spent their lives studying medicine and learning with their patients.

The doctors and researchers who are coming here are not the typical doctors that we see in primary care… these are people I think who are much more like us, people pushing the envelope a bit and open to learning, but also have much deeper knowledge of the biology, pharmacology and risks, so I think we have a lot to learn from them.


Interesting thing is they never mention the dose of the man who OD’d on vitamin D. They do mention that his blood levels were 380 which is the maximum value the test can test for (so it may have been even higher!) When I was taking 5,000 IUs a day, I registered a 30 which was 1 pt away from deficiency. I want to get to 50, so I’m taking 10,000 IUs a day (0.25 mg).

I’m pretty sure the extra 0.125 mg (5000 IUs) won’t pop me up into the danger zone. I’ll know for sure this summer when I have it tested again. The problem is that everyone’s biologies are so different. I am probably an under-absorber of vitamin D so I need to take more.


Actually, I am trying to emulate Bryan Johnson’s stack. I am of similar age and size so I think his stack may be what I should be using. I am thankful that he’s testing out all these supplements. Thanks, Bryan for being my guinea pig!