Testosterone and Weight Loss
There are a lot of questions surrounding weight loss and testosterone. On this page we are going to cover a lot of very important ground, so be ready! Here are the basic topics that we are going to deal with below:
I. Hypogonadal testosterone levels caused by being very overweight or being obese
II. How weight loss can double testosterone levels
III. How rapid weight loss and intense exercise can destroy - yes, destroy - your testosterone levels
IV. How TRT (Testosterone Replacement Therapy) can help with wight loss
Of course, if you are only interested in one of these topics, skip ahead to the pertinent section.
I. Testosterone Therapy and Weight Loss
One study on severely obese men found that their average testosterone was 223
ng/dl.  That hurts just to think about it! This is VERY low testosterone and will often lead to many of the
classic low testosterone symptoms: low libido, erectile dysfunction, loss
of morning erections, fatigue, depression, osteoporosis, anemia, hardening of
the arteries, etc. They then compared these
men to age-matched controls, whose average testosterone was 599 ng/dl, and found
that the difference was 268%! What happens is that profound weight gain
halts testosterone signaling from the hypothalamus. Basically, your
hypothalamus gets fooled into thinking that you have a lot of testosterone - due
to the fact that your estradiol is so high - and GnRH drops like a rock.
So, ironically, your testes are ready to go and able to pump out testosterone,
but there's nothing there to flip on the switch!
How does your hypothalamus get fooled? The reason is that as you gain weight, your aromatase levels increase
dramatically and this extra aromatase converts your testosterone into estradiol,
the "bad estrogen." This leads to ever-increasing levels of free estradiol
to free testosterone and, when this ratio goes high enough, it shuts down the hypothalamus output
as mentioned above.  And, again, as we'll show below, the low testosterone levels
will also make it MUCH more difficult to maintain one's weight, creating a
viscious circle of testosterone loss and weight gain.
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II. How Weight Loss Can Double Testosterone Levels
It should be noted that this does not just apply to the morbidly obese. One study of men with
significant visceral fat showed that
dropping about 35 pounds led to a 15 percent increase in free testosterone. 
Other research showed that losing between 57 and 283 pounds produced even more significant changes in testosterone:
average total testosterone levels went 240 to 377 ng/dl, a sizeable 58% rise on average.
Free testosterone also increased by 41%.  Again, the men who lost the most amount of weight probably doubled their testosterone levels.
This is why on the Peak Testosterone Forum I always try to
ask men with low testosterone how overweight they are. I am not trying to
get personal, but feel that it is important to let them know that weight loss can
very significantly boost their T in most cases. And it will also
lower estradiol which will very favorably alter their all-important
testosterone-to-estradiol ratio. I discuss this and other strategies in my
page on How to Improve Your Testosterone-to-Estrogen (Estradiol) Ratio.
Have I seen this in real life? One of our longest term posters reported:
"I have a friend who weighed 238 pounds, his testosterone fluctuated between
439-500 Ng/dl. Once he spent a few years reducing his weight to 170, changing
his diet, exercising, getting hydrated, his testosterone went back up to the
750-800 ng/dl range." 
III. How Rapid Weight Loss and Intense Exercise Can Destroy Testosterone
If being overweight can make you hypogonadal and weight loss can double or more your testosterone (in some cases), then obviously you want to lose weight as rapidly as possible, right? And you probably want to add in some intense exercise to accelerate the process even more, correct? Wrong! That might seem logical, but nothing could be further from the truth
unless perhaps you are a man not on TRT (testosterone replacement therapy).
This was shown powerfully in a study that I documented in my page on A Protocol to Lose Weight Rapidly and Maintain Muscle.
The participants in this study did something remarkable: they combined a wide variety of intense exercises with a 40% reduction in calories and
lost 11 pounds and either maintained or even gained some muscle. This is not an easy thing to do and so I did a page on that.
However, one of the guys on the
Peak Testosterone Forum read the fine print and noticed that the testosterone levels of the
men in the study dropped from 507 to 126 ng/dl! That is an ugly fall in testosterone and left those men severely hypogonadal.
IV. Testosterone Therapy and Weight Loss
Okay, so we know that gaining weight can lower testosterone. What about
going the "other direction?" If you add (external or
exogenous) testosterone, will you lower body fat? It turns out that many studies say 'yes', especially if you are hypogonadal.
Let's check out a few examples:
1. Hypogonadal Males. One study found that giving hypogonadal males
testosterone enanthate, which is very similar to the cypionate that is used in
the U.S., resulted in a loss of 13% subcutaneous fat.  Remember:
participants were not put on any type of an exercise program but rather just
lost weight - somewhat miraculously - from the HRT itself. Yes, that's the
Power of T!
2. Middle-aged Obese Males. Giving HRT to middle-aged, obese males
lowered visceral fat but not subcutaneous fat in study.  Visceral fat is "belly (or
stomach) fat" and is deadly. It is commonly associated with insulin
resistance and MetS (Metabolic Syndrome). Of course, obese males will very
likely be low or lowish in testosterone and may even be hypogonadal.
Another study showed that weight loss (with testosterone undecanoate) may be more
pronounced on the obese and found that "More than half of the men (53%) lost at
least 33 lbs., and almost a third lost 44 lbs. or more weight. Similarly, 86% of
the men had a least a 2-inch reduction in waist circumference and 46% dropped 6
inches or more." These are impressive numbers and what was really
remarkable is that the men kept losing weight generally all the way through the
five year point. This is the opposite of what usually happens with dieting
where the typical guys' weight yo yo's back and forth. 
NOTE: For more information, read my
links on Visceral Fat and Metabolic Syndrome.
3. Prostate Cancer Patients. As you may know, prostate cancer
patients are often given anti-androgen pharmaceuticals and in one study this
lowered patient testosterone levels by almost 80%. As might be expected,
weight increased by 1.8% after 12 months and the percent fat mass increased by
11% after about 12 months.
4. Steroid Users. One study noted that lean body mass increased in a
somewhat dose dependent manner with men on HRT gainng a little Lean Body Mass and
those on steroids gaining still more. As you know, steroid users go
"supraphysiological," i.e. beyond the typical max values experienced by a young
male (~1200 ng/dl). Thus, researchers could look at values even well
beyond 1200 and see that HRT made a difference. (Steroids can also shut off
your testosterone completely if done incorrectly.)
If you look at the cases above, particularly #1 and #2, you see that testosterone
works very well for the special cases where men are likely deficient in
testosterone. But what about in normal, health males? Well, one
study looked at this and found that, even though total testosterone was only
increased by 30%, visceral fat accumulation was fought off in healthy senior
males.  So testosterone therapy will likely improve outcomes for almost any
Now I do want to issue a caution here: I have heard that some of the HRT
clinics are putting out ridiculous ads where they claim that testosterone will
melt the pounds off of you like lipo. This is simply not the case.
The studies (overall) show that testosterone therapy results in mild weight loss
and is an aid in management of the same. The big guns are always diet and
exercise and, I would argue, sleep.
about your erectile strength? Can weight loss improve that as well. Of course, anything that boosts your
testosterone and testosterone-to-estradiol ratio is likely to help improve your
bedroom performance. But weight loss goes way beyond just improving your
hormones. For every pound lost, you drop a point in cholesterol for
A similar drop in C-Reactive protein - a standard measure whole body inflammation
- occurs with each pound lost as well. This drop in inflammation is very
important, because "circulating CRP levels were significantly higher in obese
men with erectile dysfunction as compared with obese men without erectile
dysfunction."  Arterial inflammation can lead to endothelial dysfunction and
arteriosclerosis, both of which can lead to erection problems in the short and
long term, respectively. For more information see my page on
Weight Loss and Erectile Dysfunction.
1) Total testosterone was improved as well.) [Diabetes, Obesity and Metabolism,
May 2004, 6(3):208–215, "Changes in sex hormone-binding globulin and
testosterone during weight loss and weight maintenance in abdominally obese men
with the metabolic syndrome"
2) The Journal of Clinical Endocrinology & Metabolism, May 1 1988,
66(5):1019-1023, "Effect of Massive Weight Loss on Hypothalamic
Pituitary-Gonadal Function in Obese Men"
3) The Journal of Clinical Endocrinology & Metabolism, Dec 1 1977,
45(6):1211-1219, "Low Serum Testosterone and Sex-Hormone-Binding-Globulin in
Massively Obese Men"
4) Medical Hypotheses, April 1998, 50(4):331-333, "The role of estradiol in the
maintenance of secondary hypogonadism in males in erectile
dysfunction"][International Journal of Impotence Research, 2003, 15:38–43,
"Oestrogen-mediated hormonal imbalance precipitates erectile dysfunction"
5) Med Hypotheses, 1998 Apr, 50(4):331-3, "The role of estradiol in the
maintenance of secondary hypogonadism in males in erectile dysfunction"
6) Journal of Clirncal Endocrinology and Metabolism, 81(12), "Increase in Bone Density and Lean Body Mass
during Testosterone Administration in Men with Acquired Hypogonadism"
7) International Journal of Obesity and Related Metabolic Disorders, 1992,
16(12):991-997], "The effects of testosterone treatment on body composition and
metabolism in middle-aged obese men"
8) Journal of Endocrinological Investigation, 2004, 27(7):665-669, "Erectile
dysfunction associates with endothelial dysfunction and raised proinflammatory
cytokine levels in obese men"
10) The Journal of Clinical Endocrinology & Metabolism January 1, 2008 vol. 93
no. 1 139-146, "Testosterone Therapy Prevents Gain in Visceral Adipose Tissue
and Loss of Skeletal Muscle in Nonobese Aging M"