This assumes (it seems to be universally assumed in this thread) that the earlier average level of testosterone - meaning the year 1999 - is more optimal, which doesn't seem evident to me.
Why not, equally: a toxin has possibly been removed?
Testosterone has well-studied correlations to muscular health and the tuning of status in social behavior. Going further, it also affects behavior in a way which I can only label as agentic: it's correlated with motivation, vigilance, and low levels of anxiety or fear.[0]
I choose these words for two reasons. First, the ratio of muscle to fat is important for most any metabolic disorder (this means both diabetes and obesity, which are comorbid). Muscles are actively important in metabolic health as they burn calories through use. And contrariwise, among their other problems, fat cells store and secrete estrogens, which is problematic for those that wish to identify as cis male. Clearly some level of the growth cascades that testosterone produces is useful for metabolic health, if not testosterone itself. Else we get into an obesity spiral and limit the development of our own bodies.
Second, high testosterone is often associated with anti-social outcomes like violence. While this is (weakly!) true, this isn't the whole truth. For instance, people given testosterone actually produced fairer deals vs non-blinded placebo.[0] So it seems more appropriate to call testosterone a status regulator than an aggression hormone.
Let's say we avoid the view that no testosterone is good – this would be ad absurdum considering its central role in the body's development. Even if you were to disagree as to basal level of testosterone in 1999, there are clear positive outcomes associated with testosterone which we can organize our sense of what is optimal around; it is possible that we have swung too far, and our current levels are not good enough.
To deny the positive aspects of testosterone, is to deny its usefulness to metabolic health, to regulating status, and maintaining the spiritedness to engage with life.
I think this comment illustrates a significant problem of people's (including some scientists) thinking around testosterone.
I'm identifying that people are only suggesting positive aspects of high testosterone and ignoring the negative. And, you are again reiterating the positive aspects in a biased, almost spiritualised way.
Clearly, as you suggest, 100% testosterone is absurd and not desirable, so there must be some limit to the amazing wonder-drug testosterone. Excessive testosterone is harmful to health apart from in behavioural changes (it's linked at least to heart failure).
What we're doing in this line of thought is negotiating that limit.
My remark was that no testosterone is absurd due to the critical role it has in development, providing a bound on what it would mean for testosterone to be a toxin. Some is good. I acknowledge that having high-enough testosterone levels to the point where heart failure and prostate cancer is implicated, would be difficult (although if true, the effect is non-linear: this study did not replicate issues with heart disease, nor did its citations[0]). So too much is bad. If you insist on framing testosterone as a toxin, then the dose will make the poison as well as the cure.
(100% testosterone is a nonsense quantity since you can always raise blood concentrations, but let's put it at values greater than 1000ng/dl for most people)
A universal drop in testosterone within at least the US, with something leftover to explain after controlling for lifestyle factors, and no sign of stalling in the trend, brings us to a conundrum. If we do nothing, and testosterone decreases faster than it used to, and some testosterone is good, and no testosterone is bad, but too much testosterone is bad, should we stop the process? Unless you set the "too much" to be much lower than what has been medically accepted, the answer must be yes at some point.
Since this is about picking an optima, what is at stake is whether or not testosterone levels before the 2000s were responsible for outsized rates of heart disease and prostate cancer (or other morbidities), and if this is true, whether or not the problems gained through the decline of testosterone weigh off the cost of its presence. We could include other externalities like status-seeking behaviors or sperm counts, which would make the comparison harder but more honest.
What I expect - I am not sure - is that testosterone's presence in heart disease (not prostate cancer) will be comorbid with testosterone-independent factors, such as diet/exercise. And since the norm seems to be testosterone declining with age I would be surprised if pushing that curve towards youth ends up being a good thing.
Feel free to challenge these assumptions, but I really think what we need to do is debate the weights.
> I'm identifying that people are only suggesting positive aspects of high testosterone and ignoring the negative. And, you are again reiterating the positive aspects in a biased, almost spiritualised way.
I am curious why you would use the word "spiritualized". I was not invoking the supernatural within my argument (the word "spiritedness" doesn't count; its meaning is secular). The emphasis on positive factors is because I'm debating your emphasis on the negatives. Attempting to frame the argument as spiritual without pointing to particulars is to add connotations of irrationality which aren't there. It is true that I am arguing emphatically.
> If you insist on framing testosterone as a toxin
I didn't intend my argument that way.
I was responding to the parent who was proposing that some environmental toxin had been introduced since the 1990s resulting in lower testosterone levels in men, seemingly from an underlying assumption that high testosterone is inherently good.
I was challenging that assumption directly. It seems at least equally plausible that some environmental toxin has been removed since the 1990s (to be specific, lead would be a good candidate) resulting in lower testosterone levels in men.
If you look at photos from the 90s and from the last couple of years people were very obviously much healthier in the 90s. Maybe it wasn't optimal, but without further evidence I'm going to believe it is closer to optimal than where we are now.
Back in the 90s we didn't all have phones in our pockets with high quality cameras. If someone got out a camera, it was a special occasion where people probably looked nice to begin with. On top of that, the pictures you see from the 90s are the pictures people have kept for 20 years - again creating a bias for situations where people looked nicer than they were day to day.
If you exclusively look at pictures from the 90s of people doing mundane things like shopping at a grocery store, they don't look any different from people today (except perhaps with worse fashion sense).
The average american woman weighed 163.8 lbs in 1999, she weighed 171 in 2020. Average BMI increased from 28.2 to 29.1 in the same time period. Women on average added 2 inches to waist size.
Men went from an average weight of 189.4 to 197.9 in the same time period and BMI went from 27.8 to 29.1. Men on average added 1 inch on waist size.
A 5% increase in weight over 20 years might be concerning from a public health perspective, but it's not something you'd see just by looking at people.
The internet exposes us to astronomically more people than we ever could have seen in the 80s and 90s. Really heavy people are still rare today, but if you look at enough pictures of enough people, especially if these sites showing these pictures self-select for oddities, you're going to see quite a few, which makes them seem much more abundant today than they really are, plus much more rare in the past than they really were.
Again, look at pictures of groups in candid settings and you'll notice similar levels of obesity.
If health has declined and testosterone levels have declined then absent any other information I am going to assume that the decline in testosterone is at best uncorrelated with health. Now, maybe there is a reason to assume that lower testosterone levels are actually healthier but I'm going to trust my eyes for the time being.
At the same time you are hiding information by taking the global average as the proper baseline for comparison. This is disingenuous here because the original study picked a US cohort. The factors that are responsible for global health indicators improving might be, at least in principle, cancelled out in the US.
This assumes (it seems to be universally assumed in this thread) that the earlier average level of testosterone - meaning the year 1999 - is more optimal, which doesn't seem evident to me.
Why not, equally: a toxin has possibly been removed?