Since yet another friend has had this become a major health issue recently... And unfortunately, so many men still don't have good information about low testosterone, what causes it, and the impact it has...
Just a little primer for those who aren't familiar... It's a bit long, but it's the minimum to explain the problem... And it's important for all mens health.
After ages 18-24, 27, and particularly after age 35, and 45, there are substantial changes in average natural testosterone production levels, with lower shorter peaks in T levels, and longer lower troughs.
There are also changes in the bodies efficiency and effectiveness at taking up and using T in the bloodstream.
At the same time, the body tends to naturally convert more T into undesirable amounts of estrogens and other anti-androgens; as well as producing changing levels of Leutenizing Hormone, Human Growth Hormone, Follicular Simtulating Hormone, DHEA, and other hormones and , which impact general mental wellbeing, energy, focus, motivation and drive, muscle mass and tone, fat creation and retention...
...basically everything about your body, and a hell of a lot about your personality.
The higher your bodyfat is above around 14% (possibly as broad a neutral range as 12%-18%, but it appears that for most, the negative effects begin worsening at around 14%) the more testosterone production and uptake are suppressed, the less effective the body is at using the T it uptakes, and the more T is aromatized into estrogens and other anti-androgens (as well as all the other "good" hormones being reduced, and the "bad" hormones being increased).
Other illnesses such as diabetes and other insulin related issues can dramatically worsen this. As can thyroid issues, pituitary issues, excess cortisol, and other adrenal issues... Pretty much every endocrine disorder.
Also, if you have naturally higher levels of estrogens, for example if you are gynocomastic naturally (as a significant portion of men are, including me), this worsens DRAMATICALLY.
One issue that most don't understand, is that even a small thyroid deficiency... "Within normal range", but on the low end of the range, can HUGELY impact testosterone (and all of the rest of the endocrine system, your health, your energy drive and focus, and your wellbeing... "sub-clinical thyroid deficiency, should be eliminated from doctors vocabularies, because there is no such thing).
Also, what doctors regard as "low normal" levels of Testosterone, are essentially the same as 75 year old men. They are paranoid of the DEA penalizing them for over prescribing Testosterone, and are very reluctant to supplement someone unless they are persistently under 300ng/dl peak, and under 100ng/dl trough.
Testosterone levels this low, subject men to substantial negative health consequences, including dramatic muscle loss, fat gain, cardiac health problems, mental focus and acuity problems, depression (often severe), anxiety, personality changes, sexual dysfunction, sleep pattern disruption, developing or worsening other endocrine linked health problems such as diabetes, and substantially increased risks and severity of several forms of cancer.
These include a 50% or greater increase in the chance of developing aggressive prostate cancer, and several times the chance of developing male breast cancer. In general, low testosterone correlates with at least a 50% increase in risk of a lifespan reduced by at least 10%.
However, that isn't the whole story, by a long shot. One need not be nearly so severely deficient in testosterone to suffer significant negative health impact.
Testosterone levels under 700ng/dl peak, and under 300ng/dl trough, are not considered "low testosterone" by most doctors. In fact, they are considered "normal to high normal" for men over the age of 35.
However, at any age, testosterone levels persistently below 700/300, are low enough to make men depressed and anxious, lethargic and sluggish, lose muscle mass and tone, gain more fat, retain water, gain weight, have significant negative health impacts and complicate and worsen other health issues (as above), and generally feel like crap. This is aside from the common issues of loss of sex drive and desire, and intermittent or persistent sexual dysfunction.
You'll note, these effects are also those that suppress testosterone even further, driving it ever lower, in a vicious spiral.
By the time many doctors are willing to supplement, they have to work 3 or 4 times as hard, to get even above 300/100, never mind 700/300... And then, most are not willing to supplement enough, for most men to stay consistently above 300/100.
You have to insist on enough testosterone, frequently enough, to get your peaks above 700, and lasting at least a few days, and your troughs above 300, and lasting no more than a few days. You can force the issue with testing if necessary.
For most people, after the initial 3 months of supplementation (which may be at a higher level more frequently) that means injecting at least every 3 weeks, and may mean injecting every two weeks, every week, or even more often (though more than once a week after the initial period is rare).
It is also important to note, that once one has actually reached such a low level of testosterone that one is experiencing significant symptoms, or when one has bodyfat above 18% to 20% or so (and particularly above 24% to 28%); transdermal patches and gels are substantially less effective (in fact, they are essentially ineffective unless you have almost no testosterone at all) at raising available testosterone in the blood stream.
Even worse, they generally result in greater aromatization of testosterone into estrogens... Which actually suppress the action of testosterone even further.
If this is happening, raising your dosage actually makes the aromatization worse, but may show "sufficient testosterone in the bloodstream", on tests.
So you're counteracting the "sufficient" testosterone you have, and in fact making your symptoms of low testosterone and excess estrogens MUCH worse (especially the depression, muscle loss, fat gain, water retention, gynocomastia, sexual dysfunction, and increased cancer risks).
And yet, these treatments are also several times the cost of injectable T.
Unless you're skinny, with low bodyfat, and you aren't really very low on testosterone, you really need deep intramuscular injection.
Even with IM injection, many men on supplementary testosterone need aromatase inhibitors, to prevent the same issues with excess conversion to estrogens.
This is particularly true if you inject more than 1ml at 100mg/ml every 3 weeks, and almost without question if you have high bodyfat, gynocomastia, high estrogens in general, high cortisol, diabetes, or inject more than 2ml every two weeks.
Unfortunately, as with prescribing enough testosterone in the first place, many doctors are reluctant to prescribe aromatase inhibitors... Again, because they are worried about the DEA penalizing them, for prescribing "performance enhancing substances".
As far as the DEA is concerned, every man wanting to have their heatlh, sex life, drive, motivation, energy, and focus back to near what used to be... Is just another steroid abuser.
You have to advocate for your own health here. If your doctor isn't willing to do what is necessary, find a sports medicine specialist, or a mens endocrine health, or mens sexual health specialist, and they will.
You might not think it's worth the time, or the cost, or the pain of injections, or that it won't have a significant impact anyway... and it's just because you're getting older, or getting fat or... whatever justification you may have...
I guarantee you, keeping your testosterone above 700/300, is worth every bit of trouble it takes to do so... and a lot more besides