I'd strongly suggest that testosterone supplementation be the last resort. Among other things, it reduces your own testosterone production and can shrink your balls!
Exercise is the first and most effective way to increase testosterone levels. If someone is too lazy to exercise then they will have a lot of other health issues that will interfere with their sex life.
Here is some medical insight into testosterone supplementation from "The Urology Times". Basically, once you start with supplementation, it becomes a lifetime need because your balls shrivel up and shut down.
That's fine for older guys whose testosterone production naturally slows down and can't be reversed through exercise. Or younger guys who do not respond to other treatments including REAL exercise and therefore have a biological/genetic hormonal problem. But it is too often and easily prescribed.
Testosterone dependence: How real is the risk?
Richard A. Watson, MD
Men are being too easily enticed lately into ill-advised use of
testosterone supplementation. Even men with only minimal, vague complaints are promised a hormonal fountain of youth and ageless virility. Many potential candidates seem to be under the misconception that “T” replacement will boost or energize their natural testicular production.
In fact, exogenous testosterone suppresses testicular function.
Before embarking on a trial of testosterone rejuvenation, men need to be made fully aware that, if and when they ever decide to discontinue testosterone supplements, their recovery from drug-induced “low T” may be highly symptomatic and prolonged. In some cases, testicular function may never return, even to its pretreatment baseline.
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Once the treatment is stopped, men can experience withdrawal and severe depression,
as well as the permanent inability to naturally produce testosterone."
The full article is worth a read.
https://www.urologytimes.com/view/testosterone-dependence-how-real-risk