[00:01] actually know why testosterone levels stopped declining and started going back up because obesity rose from roughly 35% to 39% moving exactly the wrong testosterone. Population level analyses give very little clarity to your
[00:16] specific situation. How do you maximize your own natural testosterone levels? If you're doing all that and your test levels are still low, you might want to consider TRT, but the question is how and when.
[00:30] >> Hey guys, Dr. Mike here for RP Strength. We've heard for years that our testosterone levels are falling. >> No. >> McGainz. And it's kind of scary.
[00:43] But recent research says they're rising. recent research says they're rising. Like, seriously, what is going on here? Let's dig in. Here's the popular story. It's that modern men have dramatically
[00:57] less testosterone than their fathers or grandfathers did. involved, really, cuz you got a lot of interesting takes here, testosterone has 30 and 50% or approximately one entire real adult
[01:14] Viking per generation. Scott, aren't Viking men like the ultimate >> Yeah, for sure. >> How do Vikings in your mind compare to pirates and lumberjacks? >> I mean, Vikings are top because they
[01:26] have like the beards and the long hair and stuff and they pillage same degree. >> No. They do low-key pillaging. eye patches. That's not
[01:40] And lumberjacks are just good-hearted people, Scott, just >> Doing wholesome >> Wholesome work. >> So, the exact headline here is shaky, but this headline of test levels are
[01:55] falling did grow from several legitimate secular trend findings rather than from like pure internet vapor which a lot of other myths come exactly from pure other myths come exactly from pure internet vapor.
[02:08] Now, there have been also declines in testosterone that could be attributed to other factors that can be corrected for in these analyses. For example, aging.
[02:21] Testosterone tends to decline as an individual man ages. But a secular decline adjusts for that. That means a 40-year-old tested in 2005 has less testosterone than a comparable 40-year-old tested in 1990.
[02:37] Age adjustment attempts to separate the population got older from same-age men now have lower levels, which is a very different claim. Aging Study, produced one of the strongest early signals. Researchers in
[02:52] this study analyzed 1,532 men from the Boston area. Hey, Boston. men from the Boston area. Hey, Boston. Whoa. Cat. Hey, Scott, my cat's got low doing. I don't know what that was.
[03:05] Matt Damon, help. This gave us 2,769 observations across the late 1980s, the 1990s, and even through the early 2000s.
[03:17] What they found is that a substantial population-level decline that was greater than the decline expected from aging alone. So, something is definitely was definitely going on here. That decline actually survived a bunch
[03:31] of other adjustments for several obvious suspects. which is huge, changes in smoking, medication use, and general health. They didn't fully explain the Massachusetts trend.
[03:46] Now, they explain a huge amount of the variance that other studies site. So, the Massachusetts study decline was much explained some. So, they didn't prove that these factors
[03:59] had zero causal role, but it means the finding could not simply be erased by saying, "Oh, it's just BMI." >> [gasps] >> It seems like some real testosterone decline was actually occurring.
[04:12] you would think maybe this is only a US trend of testosterone going down, but a very large Israeli healthcare dataset, Israel's at the other end of the world, points in exactly the same direction.
[04:26] Investigators there examined testosterone tests from over 100,000 men testosterone tests from over 100,000 men between 2006 and 2019 and reported a highly significant age-independent decline across most age groups. Scott,
[04:38] ready? Oy, my testosterone levels and I know, wait, wait, those aren't Brooklyn Jews, Israeli Jews. Uh let's see if I can get my Israeli Jew going. Um eh, you know, testosterone, it's what whatever, that's life, no?
[04:52] I would say other things, but um but the Israeli Jews I don't with. the strongest version of the decline claim seems actually credible. So, we're
[05:06] not here to say that the decline never occurred. Several populations, periods show lower testosterone in men tested later, which take care of most of the difference, but not all.
[05:21] The effect may in fact be biologically meaningful, and everyone merely got older and fatter is not the complete explanation. Now, as is often true about the internet, the number of claims as to why our test levels have fallen is
[05:33] enormous. Here are some that have serious evidence shakier. For explaining the overall decline over time, obesity is probably the biggest proven contributor.
[05:47] More body fat lowers total testosterone, while severe obesity also suppresses doing stuff to your body. In a recent NHANES data set, obesity was linked to about 2.7 times the odds of
[06:01] having a testosterone below the minimum cutoff of 300 ng per deciliter. Guys, that is a huge deal. And last I checked, obesity from 1970 to 2010 or
[06:13] 2020 has massively increased, so this tracks. tracks. Next, insulin resistance, diabetes, and chronic illness also matter. Impaired fasting glucose raised the odds
[06:26] of low testosterone by about 55%, while diabetes range glucose nearly tripled The relationship also runs both ways, since low testosterone may worsen body composition and make metabolic health worse, which lowers testosterone levels,
[06:40] gnarly. And all of these, insulin resistance, diabetic outcomes, glucose handling, and testosterone itself are made worse still via obesity. So, first of all, obesity is a big deal here, but even without
[06:55] obesity, insulin resistance and other things can interfere with testosterone levels. And this is a massive epidemic in the United States for a huge fraction of people. Diet composition is often proposed.
[07:07] Might have small effect, but no food or food group is the endocrine assassin all by itself. Some small studies find slightly lower testosterone on very low-fat diets, but almost no Americans eat very low-fat diets. While newer
[07:21] difference. Here's a myth we're just going to kibosh right now. Soy and related isoflavones do not appear to lower male testosterone. This has been studied to the ground. I do give you permission to
[07:35] kidding. Just kidding, guys. Easy. Pass the Just kidding, guys. Easy. Pass the blunt. Or maybe not. Or maybe not. Because cannabis may lower testosterone. May lower
[07:49] And it's tough to see if it's the cannabis itself or the degradation in sleep quality that cannabis extreme use causes. Other factors can be in play as well. Pollution, heat, alcohol, stress,
[08:03] depression, and modern work patterns may each play a role in reducing test levels. Some of these affect sperm more clearly than testosterone, and many effects appear small or strongest only at very
[08:15] None of these are major players to explain the trend, unfortunately. endocrine-disrupting chemicals. Now, that's plausible, but it's not a
[08:27] Phthalates, BPA, PFAS, and similar compounds can affect reproductive biology, and some are associated with low testosterone, but the human evidence is observational and very messy. So, plastics caused
[08:41] everything is a far too confident of a take, though it could be true in part. the entertaining suspects for testosterone reduction are mostly weaker or unsubstantiated. Porn, masturbation, ejaculation, tight underwear. Scott, I
[08:56] that very tight underwear reduces testosterone levels. Can you believe >> I just thought it was sperm count. >> Yeah. Here's another one, it gets >> Oh, jeez. >> Right? Phones in your pockets, soy
[09:09] burgers, and insufficient lumberjacking, which is otherwise a serious national insufficient pirating and insufficient oil rigging, have all been accused. Sexual activity can briefly shift hormones, but there's no good evidence
[09:23] that masturbation caused decades of falling testosterone. Scott, I'm back in >> [laughter] >> All right. So, test levels are falling, and it's mostly obesity, but a combo of other smaller factors
[09:36] obese. But wait, are they still falling the testosterone levels? Because our data set that we just talked about ends in the 2010s. Here's the wrinkle. A just published study in 2026
[09:51] analyzed over 10,000 American men across nationally representative NHANES cycles nationally representative NHANES cycles from 2011 to 2016 and from 2021 to 2023, much more recent. And remember, testosterone has been sort of falling
[10:06] for much of the time before this. Testosterone deficiency in these analyses was defined as total testosterone below 300 ng/dL. excluded and measurements used CDC standardized LC-MS/MS methods, which is
[10:23] standardization. We can be more confident. Across the entire sample, 25.7% tested below 300. That doesn't mean a quarter of the US
[10:35] male population, or at least as sampled, has clinical hypogonadism, which also requires symptoms and repeat morning testing. It does mean that a lot of folks have very low testosterone levels and
[10:47] would probably benefit in my experience and my estimate from testosterone about it. That being said, some folks coast on 300, some folks are miserable on 400. But from the beginning of the data set
[11:01] to the end, roughly from 2011 to 2023, age standardized raw testosterone levels below 300 ng/dL, how many for what fraction of the testes how many for what fraction of the testes had below 300 ng/dL test, fell from
[11:16] 29.3% to 22.4%. range glucose, and 8 plus sedentary hours all predicted low testosterone as
[11:28] expected, but while most of these went up during this time. >> [snorts] >> Or rather, the fraction of people under >> Or rather, the fraction of people under the test low cutoff declined a ton. I
[11:43] the test low cutoff declined a ton. I mean, 29.3% to 22.4% in a massive thousands of people sample is a big deal. In fact, that trend of increasing testosterone levels, or rather less of a
[11:56] decrease, that trend survived survey waiting, age estimates, and sex hormone binding globulin related sensitivity analysis. During that time, obesity rose from 35.1%
[12:11] 35.1% to 38.9%. Damn, Scott, the 20 teens were a time for obesity, huh? Holy crap. >> [gasps] >> Low testosterone during that time declined, the opposite of what obesity
[12:24] alone would predict. Now, the paper mainly measured the fraction below 300, not population mean testosterone. improve without every percentile rising equally. And a recent rebound does not
[12:39] Testosterone could have fallen for decades and then partially recovered. Both findings can be true. But even if partial recovery is real, why are test levels going back up? We have a few hypotheses.
[12:54] Extreme sedentary time fell from roughly 40% to 36%, which could have provided some upward people are a little bit less inactive, a bit Access to regular health care improved slightly, potentially help identify and
[13:09] treat obesity, diabetes, sleep apnea, and medication-related problems, but those are all true except for the obesity part, because obesity rose from roughly 35% to 39%, moving exactly the wrong direction to explain higher
[13:21] >> [gasps] >> Diabetes range fasting glucose barely nearly triple the odds of low testosterone. Smoking declined, but smoking. Smokers often show higher total
[13:36] testosterone or sex hormone-binding globulin. Obviously, smoking remains spectacularly unhealthy and interferes with muscle growth, too. getting from training, which is really terrible, but it does keep your test
[13:49] levels high on paper, and all the cool celebrities do it, which is why I smoke completely honest. Age can't explain the increase because it survived age standardization. Now, unreported testosterone
[14:02] supplementation, steroids, hCG use, clomiphene, or enclomiphene could have inflated the results. Although, excluding values above 1,000 ng/dL barely changed the results, and very few people actually get these
[14:17] treatments. To complicate matters, COVID created a large sampling gap and may have changed who participated, how they lived, and how healthy they were. So, the honest answer is that we don't
[14:29] actually know why testosterone levels stopped declining and started going back I mean, at least I don't. Who the hell is we? I'm having a schizophrenic episode again. The result probably reflects some
[14:42] mixture of real recovery, maybe some health care changes, conditions, and assay differences. Ah. Not very compelling. But for you and your test levels, it
[14:55] doesn't have to be, and here's why. It's because population analyses are It's because population analyses are very, very limited and always were. Population level analyses give very little clarity to your specific
[15:09] NHANES tested different men in each cycle. It did not follow the same people from 2011 to 2023. representation, but cannot perfectly correct for participation, survival,
[15:22] subgroup changes. Population averages can shift with age, obesity, health, medication use, smoking, alcohol, income, sleep, diet, exercise, and work patterns. Morning ver- versus afternoon testing,
[15:36] meals, sleep loss, illness, dieting, and hard training can all change individual results. Also, the 300 cutoff creates a bit of an artificial cliff. A man at 299 and another one at 301 are basically in the
[15:48] splits them into you're totally fine and you need help. Sexual activity may cause brief hormonal fluctuations, but masturbation frequency is unlikely to explain a national multi-decade trend. And also the
[16:01] reversal of that trend. Endocrine disrupting chemicals may matter, but mixtures, confounding, exposure measurement, and reverse causality. Some of the best insights onto this have proven to be kind of worthless.
[16:14] The biggest deal here is the double inference problem. We barely know why the average changed. And the average still cannot diagnose you. Symptoms, health, medications, fertility goals, and repeat testing matter far
[16:28] more for your levels. But before considering all of that, there are massive things you can do to boost your test levels personally. What society is doing, how do you maximize your own natural testosterone
[16:42] levels? Here are the big hitters. First, get consistent high-quality sleep, usually around 7 to 9 hours, and treat serious sleep disorders like apnea ASAP. Next, lose excess body fat when obesity
[16:56] is present. Substantial weight loss is probably the most reliable, broadly applicable natural intervention to boosting your testosterone. If you're over as a male about 15% body fat, losing fat is very likely to help.
[17:10] Next, avoid prolonged, severe dieting or unsustainably low body fat, especially when you're already lean. Eat enough calories, protein, essential fats, fruits, vegetables, and
[17:23] Eating a healthy, high-protein diet is a big deal. If you eat too little protein, or you eat too little carbs, or you eat or you're eating too few nutritious foods like veggies and fruits, your test
[17:38] levels won't be ideal. Cutting out entire food groups is almost always bad for test levels. Another one is to avoid periods of easier said than done, but it's a real thing.
[17:54] your testosterone levels won't actually change much. It is a myth that lifting hard makes your testosterone levels consistently higher. But, way too much training, too much volume, too much frequency, and
[18:06] accumulating too much duration of hard training without backing off can definitely lower your test levels. So, if you have a week of crap recovery and all else is good, deload, or just take the week off.
[18:18] Have whatever healthy amount of sex or masturbation that suits you. Abstinence rituals, while we're at it, and most commercial test boosters, while we're at it, have little meaningful evidence for actually changing testosterone levels.
[18:31] And when you're testing your test levels correctly, two separate fasting mornings after normal sleep, while healthy and not deep into contest prep, is the way to go. And when you have your test levels checked, also check sex hormone
[18:44] binding globulin, free testosterone, ideally also estradiol, when If you're doing all that and your test levels are still low, you might want to consider TRT, but the question is how and when.
[19:00] shooting every test vial under the sun into your urethra, which is how you administer TRT, that's a joke, let's talk about some signs your test Reduced sex drive. Fewer morning erections. Infertility.
[19:15] Fewer morning erections. Infertility. Hot flashes. Testicular shrinkage. Body exhibited at some point. That never happened. Anemia, which means low iron. And declining bone density are relatively informative signs of serious
[19:28] testosterone deficiencies. Other signs can include fatigue, brain Other signs can include fatigue, brain fog, low mood, poor sleep, fat gain, and weak gym progress. A lot of these are pretty non-specific
[19:40] and have a bunch of different causes, but if they all occur together and your you're on to something. Another one is a lower desire to train. you used to be pumped going to the gym and now you're just like, "Uh." And
[19:56] motivationally. If you have these signs, especially if time, go to your doctor and ask to be examined for your testosterone levels. It's a super cheap test, so you might as well throw in FSH, LH, estrogen, free
[20:11] testosterone, SHBG and them all as well. If that comes back on the lower end and that's a conversation about potential TRT to have with your doctor. With your guys. It often ends really poorly that way.
[20:28] If your test levels are normal, but the symptoms all match lower testosterone, that's also a conversation. Because remember from earlier, what's normal for some is low for others. So you could actually still be a
[20:41] candidate for TRT even if you have relatively normal levels, but you experience all the symptoms. Now, if and when you get on TRT, testosterone replacement therapy, every few months, monitoring of values is
[20:54] your doctor to help you increase and so you can see how your measured test levels change and measure health markers, as well as like how are things feeling and how are things doing in the
[21:07] gym. Your ideal test levels are when the off the charts, right? They're in a good high average range. Your health markers like blood pressure, cholesterol, liver values, and so on
[21:20] are their best. And your mood, sexual stuff, and lifting are also at their best. It's going to take some time to get there to that ideal range for you, but you can. And then you don't have to worry about who has rising or declining
[21:33] testosterone levels in the population because you will be swimming in gains and in female ejaculate ideally. All right, guys. That's the summary. >> test levels were going down for a while. Yes, they stopped going down. No, we
[21:47] have no idea why, but your own test levels are very much in your own hands. Just like the organs that produce them. Hey, am I right? All righty. [music] Hey, am I right? All righty. [music] See you guys next time.