High levels of testosterone promote energy, drive, ambition, assertiveness, self-confidence, and purpose. Furthermore, high levels of testosterone promote status-seeking (e.g., through buying expensive cars or clothing). Some of this comes down to the way testosterone increases dopamine signaling.
However, testosterone receptors are widely expressed in the central nervous system and testosterone has effects on many brain sites, particularly in “emotional” centers of the brain. Testosterone also affects cognition in poorly understood ways. For example, testosterone improves spatial thinking and women who excel at mathematics on average have higher T-levels.
Of note, it is hard to say which of these effects are caused by testosterone itself, and which are caused by its conversion to DHT or estradiol. For example, if the aromatization to estradiol is blocked the “testosterone”-mediated increase in aggression and libido declines.
Outside the brain, testosterone has a lot of effects on pretty much every bodily tissue, which is the case for many other steroid hormones as well. For example, testosterone strengthens muscles, tendons, and bones. DHT, the primary metabolite, stimulates the expression of the typical “male” phenotype and affects the growth of the larynx, penis, hair, and prostate.
Personal experience
In my early twenties, I dieted down to very low levels of body fat, and my testosterone levels tanked. I jumped on the TRT bandwagon and replaced my testosterone levels for about two to three years. During this time, I experimented with all kinds of combinations of testosterone cypionate, HCG, FSH, and aromatase inhibitors, but the more I tried to mess with it, the worse I felt. Eventually, I settled on the simplest option: testosterone-only (100mg per week) plus a low dose of HcG (125 IU twice per week).
In retrospect, my experience with TRT was quite underwhelming. There was quite a large placebo effect associated with it as I believed that a lot of my problems with my energy, mood, health, and physique could be solved with testosterone replacement – which was simply not true.
Initially, there was a honeymoon period that lasted for a couple of weeks. After that, I have not noticed much of a benefit other than an uptick in drive and an easier time to build muscle.
It did help my physique though. The difference between left and right is roughly 10kg of lean tissue. On the left, my testosterone was borderline low and I have not yet started going to the gym. On the right, my testosterone was at the top of the reference range plus two years of dedicated training (1 hour of gym three times per week). For a picture of me 2 years after TRT with just dedicated training click here and scroll down to the section on “body fat”.
The major thing I noticed was that I needed less sleep, and I was often fine with just sleeping 6-7 hours, an effect I also experience after two weeks plus of semen retention (which interestingly does not affect my testosterone levels but presumably affects ancient neural circuitry upstream of sex hormone signaling).
Another thing I noticed was that testosterone visibly aged me. After a year on TRT, others have commented that my face seems to have grown older by multiple years. This transition from boyish to manly (which is not necessarily bad) may be in part explained by a redistribution of facial fat & a growth in facial musculature but it may also be in part because high levels of androgens drive the aging process.
To some extent, testosterone is like a peacock tail. High levels of testosterone help with signaling “good genes” but at the expense of longevity. Testosterone’s effect on longevity is U-shaped and high levels of androgens are quite bad for every organ system other than the musculoskeletal system and perhaps insulin sensitivity.
Surprisingly, coming off was much easier than expected. I simply stopped injections. I lost a bunch of water weight and my face looked overall much better. After 1 month I was back to my baseline, which is in the 600-700 ng/dl range. Some people have issues with coming off and recovering their natural levels, particularly if they have been using higher doses (e.g., for bodybuilding purposes). Fortunately, I was not one of them.
Thoughts on current trends
Recently, more and more people seem to self-experiment with testosterone. The online landscape paints a picture that everything is explained (and fixed) by the panacea testosterone. From mental health issues, to (lack of) gains at the gym, to motivation and procrastination.
Thus, thousands flock to “TRT clinics”. These clinics are prescription writing factories that will find excuses to give TRT to almost everyone. They make claims that the normal ranges are wrong and the only correct result is to be at the top of, or above, the reference range. They start people on insane beginning doses like 250mg/week because it gives them a rush to feel like it’s “working”.
Spoiler alert: A lot of people are in for a rough awakening…and a prematurely aged body.
Signs & symptoms of low testosterone
- constant low-level background fatigue
- low sex drive
- inability to build muscle
- easily fatigued during exercise
- lack of drive and motivation
- little zest for life
- poor self-confidence
- anxiety and depression
- being skinny fat
- a lot of fat over the triceps area
Diagnostics
- Blood test:
- Minimal: total T, SHBG
- Extensive: total T, SHBG, free T, E2, LH, FSH
- Signs & symptoms
Interventions that worked for me and friends
- Body fat & dieting: In my opinion, the number one overlooked reason for low testosterone is not stress, sleep deprivation, or micronutrient deficiency but caloric restriction or having too little body fat (or chronic dieting). The HPTA axis is quite sensitive to energy balance, particularly leptin levels (discussed here), which makes evolutionary sense. Conversely, having too much body fat also lowers testosterone levels, as adipose tissue expresses aromatase, which aromatizes testosterone into estradiol (E2), which then exerts powerful negative feedback on the HPTA axis.
- TRT: A decent starting dose is 100mg testosterone cypionate per week split into at least three weekly subcutaneous injections (ideally, injecting every day). While I was on TRT I used a low dose of HCG (125IU twice weekly) to preserve fertility and testicular sizehowever, it seems that daily administration is superior (e.g., 50 IU HCG per day). I only ever used insulin syringes and injected into my upper glute area.
- A note on estradiol: One friend, who is a little overweight, is a high-aromatizer. He uses a low dose of the aromatase inhibitor (AI) anastrozole to keep estrogen levels in check (0.1mg twice per week). In my opinion, the vast majority of non-obese people using physiological doses of T do not need an AI, and in fact, may do net harm by adding one. Estradiol is important for many things, from energy levels, mood, libido, cognitive function, and joint and bone and brain health.
- A note on females: Testosterone is very important for women. In fact, molecule per molecule, there is about 10 times more testosterone in women than estradiol. Unfortunately, testosterone is rarely replaced in females, which is a problem for women who take oral contraceptives or women on postmenopausal hormone replacement therapy, both of which have a large shift in their estradiol to testosterone ratio. Therefore, a gynecologist friend gives either DHEA or low doses of testosterone in addition to HRT.
- Avoid: racemic clomiphene (enclomiphene is okay, though very hard to get hold of), most TRT “clinics”, shady over-the-counter testosterone boosters, 19-nor-steroids (which are very suppressive)
Part II
I have experimented with TRT a second time. I will update this article soon. Sign up for my newsletter to get notified when the article is available.
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