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Female vs Male Physiology

Since writing The Women’s Book I get a LOT of questions about women’s physiology.  While most are from women of course, I do get some from men.   A specific question is how much of the information in that book applies to men with low testosterone and/or elevated estrogen levels.  The answer is very little of it and to understand why I need to examine female vs male physiology.

Sex vs. Gender So I don’t Get Crucified by Jezebel

Strictly speaking, sex and gender are different.  Sex is a description of biology: testicles, penis, ovaries and such.  Gender refers to what someone identifies as sexually.  A biological male can identify as a female and a biological female may identify as a male.

In research, scientists use sex and gender interchangeably with seemingly no general preference and I will too (as I do in The Women’s Book with the same pedantic note).  I acknowledge and understand that they are NOT the same thing and it’s nothing more than a stylistic writing choice with no implication whatsoever that sex or gender are relatively more or less relevant or important than each other.

Anyhow, here is a (hopefully) brief look at some of the differences that separate boys from girls.

Of Male and Female Chromosomes

Think way back to high school biology and you might remember something about chromosomes and sex.  You might vaguely remember that little girls come with two XX chromosomes and little boys come with an XY chromosomes.

These carry the genetic code that mommy and daddy provided for you when they had sex (when a man and a woman love each other very much or met on Tinder, the man puts his dingle in her hoo-ha and all of that).  Note that there are some variants on this, like the XXY that is currently causing so much furor in women’s sports and which is a topic I’m not touching here, in the book or anywhere else since the debate is mostly about politics and not science so far as I’m concerned.

But those differences provide the initial difference between male and female folks.  And in that those genetics determine a tremendous amount of what develops in the person.  No matter how low of testosterone or how high estrogen a male has, he doesn’t carry female chromosomes unless there is some strange pathology going on.  And many of a woman’s cells will develop in a fundamentally different way than a man’s for this reason.

Sometimes the differences are small, male and female skeletal muscle is relatively identical with some fairly minor differences (i.e. women’s muscle has a bit more fat in it).  Sometimes the differences are large, at least part of a woman’s fat pattern is determined by genetic contributions: even though her body fat patterns don’t develop mostly until puberty, she starts with more and different fat cells in the lower body.  So right away there’s a difference and it’s genetically set.

Male and Female Fetal Development

In addition to the baseline genetic differences, there is another place where differences get programmed into the biology although here it’s possible that there is an effect.  It’s turning out, as I wrote about in my Bromocriptine book over a decade age that a lot of human physiology is being determined and more or less programmed while the fetus (aka spawn/parasite) is developing.

For example, both gestational diabetes and a woman starving can permanently program the fetus towards obesity, metabolic syndrome, etc. later in life.  The reason, roughly, is that the fetus is being starved of nutrients (for two different reasons, but the end result is the same) and it becomes more thrifty right off the bat.  It will store calories more effectively and lose them with greater difficulty.  That’s right, what mom did during your pregnancy can screw you (or benefit you) before you’re even born.

Fetal Hormone Exposure

But there is another big player here and that has to do with fetal hormone exposure.  Sometimes a fetus is exposed to relatively higher levels of androgens in utero and sometimes it’s exposed to relatively higher levels of estrogen (or lower levels of androgens).  And this too programs a ton of the physiology.

A female exposed to more androgens ends up relatively more masculinized, her brain will develop differently as will her entire skeletal structure.   The same goes in reverse, male fetuses (fetii? where’s my Latin peeps) exposed to more estrogens or less androgens can end up relatively more feminized.  Their brain develops differently as does their skeletal structure.

It’s currently a little bit debatable if this pre-natal hormone exposure affects long-term hormone levels.  That is, does a woman who has been androgenized in utero ends up with elevated testosterone as an adult or does a male end up with more estrogen.  It doesn’t seem so but the studies are a bit all over the map.  I suspect it does but that’s it.

There is actually an easy way to test this, check your finger digit ratio.  This is the ratio of your second to fourth finger (the 2:4 ratio) and there are distinct male and female patterns.  And this is related directly to prenatal hormone exposure, hence my comment about skeletal structure.

Basically, this simple test will give a rough indication of what hormones you were exposed to before you spawned. And this ratio ends up correlating with a ton of things including toy preferences, athletic performance (male pattern is better for what should be obvious reasons), potentially sexual preference (hence my comment about biology still impacting on what someone identifies), and many others.

So what?  Well, it’s certainly conceivable that this prenatal hormone exposure, in the case of the question asker, presumably having been exposed to more estrogens in utero is programming some aspect of his physiology later in life.  In this sense, he might have somewhat more of a female biology which is what he’s asking about relative to my book.

But there’s still a difference which comes down to hormones.

Male and Female Hormones

Males and females have, relatively speaking, the same basic hormones in their body.  But the levels differ, often enormously.  Here I’ll focus only on the reproductive hormones, estradiol (actually one of three estrogen but the one that is most important to the pre-menopausal, non-pregnant female and male), progesterone, and testosterone (technically there are more androgens than just this one but that’s too much detail).   Both sexes have both hormones but it’s not that simple (is it ever).

In at least some cases, the effects of a given reproductive hormone in one gender is the opposite in the other.  Case in point, if you raise levels of testosterone in males with low testosterone, their insulin sensitivity improves.

But elevated levels in women (as often happens in something called Poly-Cystic Ovary Syndrome where testosterone may be elevated 2-3 times above a woman’s normal levels), insulin sensitivity gets worse.  Same hormone, different results in males and females.  This is just an interaction with the underlying biology, genetics, etc.

Does this happen for estrogen in males? To be honest, I haven’t looked into it in nearly as much detail since it’s not relevant to the book. In at least one case, I can think of a situation where estrogen has the same effect in males (they often inject males with estrogen to try and separate out the effects of it from progesterone in women).  D

uring aerobic activity, women use more fat for fuel and less protein.  Inject estrogen into men and the same thing happens (I can only imagine the pre-contest diet prep ideas that will come out of this.  Pre-aerobics estrogen to spare muscle?)

Is this true for other effects? I honestly don’t know since I just haven’t delved into it here.   In any cases, here are some relative levels of the different hormones in males and females.

Comparison of Testosterone and Estrogen in Men and Women

So what are we looking at here?

First the easy one, testosterone.  Women have enormously lower levels of testosterone than men, it’s usually put at 1/10th to 1/30th what is seen in a man.  Even in PCOS if a woman doubles her levels to 150 ng/dl it’s still half of a man’s low normal levels.

At the same time, women are far more sensitive to testosterone than men are due to their low levels and higher receptor sensitivity.  Small changes in women have enormous impacts, both good (muscle growth, performance) and bad (secondary male sexual characteristics such as body hair, acne, hair loss and others).  A male with low testosterone is certainly in a bad place but unless he’s hypogonadal, his testosterone levels are still significantly above the typical woman’s levels.

So what about estrogen?  Males product estrogen clearly although the range can vary.  But under female you’ll see three values ranging pretty significantly from 30 up to 370 pg/ml depending on the phase of their menstrual cycle.  Certainly a male at the high end of estrogen values may be above a woman’s lowest levels but overall his levels are significantly lower than hers at peak.

But there is more going on here.  You might notice three unknown or scary words up there: follicular [phase], ovulation, and luteal [phase].   Which brings me to the main reason that the information in The Women’s Book doesn’t really apply to a man with low testosterone and elevated estrogen.

The Menstrual Cycle

Ignoring  the differences in absolute hormone levels, perhaps the biggest difference in general between males and females has do with the menstrual cycle, the often enormous variations that a woman’s hormones go through on a (very roughly) 28 day cycle from the onset of one menstruation to the next and which is cut in half by ovulation.  Before getting into that, let me first show a male’s hormone levels across a month’s time.

Monthly Male Testosterone Levels

Ok, fine, I’m sure some endocrinology nerd is going to get into my crap in the comments that males do show some sort of vague monthly cycle in terms of hormone levels and that’s fine.  But there just aren’t huge swings on a day-to-day basis in levels of men’s hormones.  For all practical purposes, it’s a straight line especially compared to a woman’s hormone levels, shown below.

The Menstrual Cycle

Scared now?  Yes, I drew this and, yes, my drawing sucks.  You can find better pictures all over the web but this shows the basics.  In the follicular phase, right after menstruation (the name refers to the development of the follicle which will burst to release the egg), estrogen starts low and sweeps up to a big peak right before ovulation.

This is when the egg is released and implants in preparation for pregnancy (there is also a testosterone spike here that’s not on the graphic).  After ovulation, estrogen drops like a stone and then shows a gradual increase to about half the levels of the peak (the other hormone is progesterone which I’m not getting into here but it swings up to a higher level).  This is called the luteal phase referring to the corpus luteum which develops out of the follicle.

I’d note that there are an enormous number of what I call hormonal modifiers in  The Women’s Book Vol 1 that affect the above.  Birth control is a synthetic way of controlling the cycle and the types vary enormously.  Women can have elevated testosterone under a few conditions which changes their physiology.  As well.

For various reasons, women experience menstrual cycle dysfunction, the most extreme of which is amenorrhea where the cycle is lost completely.  Finally, with age women eventually enter menopause where their hormone production drops off nearly completely.

In contrast, a male’s testosterone drops gradually with age but as I’ve said recently “While women show this complex monthly cycle of hormones for several decades, men basically have one long 65 year cycle of being an asshole.”

But as those hormones change throughout the month, nearly every aspect of a woman’s physiology changes, often drastically.  Fuel use, the ability to recover or adapt to training, her mood, hunger, appetite, food cravings, potential injury, risk, pre-menstrual syndrome, etc.

And those are changing due to the swings in hormones that are occurring.  And a lot of what the book gets into is how the above changes how diet or training should or can change to optimize the system (of course I also address how the various hormonal modifiers change this and what that changes practically).

And no male, no matter how low his testosterone or how high his estrogen has that going on.  His levels are still basically the same day-to-day.  I might allow that his physiology is superficially similar to a woman with PCOS who has very elevated testosterone levels but even here, women with PCOS still show cyclic changes in hormones that a man will never experience unless he takes tri-phasic birth control or something.

So most of the information in the book simply won’t apply in your situation.   At most I might offer that you will probably have low insulin sensitivity which means lower carbs will be better.  You also should use a lower calorie surplus and maybe a lower training volume to gain muscle since you don’t have the hormones for optimal growth or recovery.  Or pick another sport than weight training.

You should still read it of course since I have bills to pay and it might help you to understand women (sort of, even I can’t solve all the problems).  But the information won’t help you that much or really apply to you.

What will help you is finding a good HRT (hormone replacement therapy) doctor to give you testosterone and an anti-estrogen to get your hormones where they should be.  At best losing body fat (which is where men convert testosterone to estrogen primarily) may help to both lower estrogen and potentially improve testosterone levels but the effects will be small compared to just getting on HRT to fix things.

And that’s the (too) long answer.

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