Total T: The Truth
Lifters sometimes brag about their total testosterone levels, but getting all puffy chested about high total T is like having a thousand bucks in your pocket and feeling rich when most of it's just Monopoly money.
Total testosterone levels have almost no value in helping us evaluate how much male hormone someone has. What matters is "free" and "bioavailable" testosterone, and those things are determined by how much testosterone is bound up by SHBG (sex hormone binding globulin) and serum albumin (and a couple of other less consequential proteins).
These proteins roam around your circulatory system, kidnapping lone testosterone molecules (along with a select group of other hormones) and chemically restraining them, no doubt putting a little peptide ball-gag in testosterone's mouth so it can't cry for help.
Of the two, SHBG is much more significant since serum albumin isn't really committed to this whole kidnapping thing; it's attachment to testosterone is only half-hearted at best, so much so that albumin-bound T is still considered bioavailable.
When you come down to it, SHBG can really be kind of dickish about holding your T levels hostage, so much so that author and medical doctor Abraham Morgentaler calls it the "joker in the deck" when it comes to evaluating a patient's T levels.
You could have high total testosterone because of your genetic predisposition, supplements, or because you're getting replacement therapy, but you still might be experiencing symptoms of low testosterone because of that damn SHBG joker.
That's why you need to know how to make SHBG-lowering adaptations to your diet or lifestyle, or, alternately, what chemical SWAT teams you can send in to rescue testosterone and set it free.
So Just How Much T Does SHBG Bind Up?
When you're a child, levels of SHBG are pretty low anyhow, but when you hit puberty, they decrease further – practically to vapors – so that there's plenty of free testosterone available to grow your muscles and assorted manly parts.
These levels stay pretty much the same – at least they're supposed to – until males approach codgerdom, when SHBG levels increase and tie up even more of the aging body's rapidly depleting testosterone levels, giving old bastards one more thing to contend with while trying to grow old gracefully.
But even young men in their prime have a lot of testosterone that's tied up and not available to do the things testosterone is supposed to do. SHBG typically binds up anywhere from 40 to 70% of a young man's testosterone, but you could have higher-than-normal amounts of SHBG.
That means that while you might have a chest-thumping, I'm-a-goddam-gorilla total testosterone blood level of 1000 ng/dl, your free testosterone might be a measly 15 ng/dl, which most doctors would still consider to be in the normal range.
Experts, though, myself included, think a level that low puts men at a high risk of every age-related disease, not to mention making it hard to put on muscle or even have the sexual energy to get off the couch, or as the case may be, get on the couch, to fornicate.
Just as a reference point, here are some age-matched "normal" free testosterone ranges for various age groups:
- 20-25 years old: 5.25 to 20.7 ng/dl
- 30-35 years old: 4.85 to 19.0 ng/dl
- 50-55 years old: 4.06 to 15.6 ng/dl
In my experience, though, men should try to maintain levels anywhere from a minimum of 20 ng/dl up to around 30, regardless of age. Part of the way we can do that is to lower SHBG.
To do that, you might have to increase test levels (naturally or through replacement therapy of some kind) to kind of White-Walker overwhelm your supply of SHBG, or work to keep SHBG levels on the low side of normal physiological levels, which is between 10 and 57 nanomoles of SHBG per liter of blood.
Are My SHBG Levels Too High?
The symptoms of overly high SHBG are pretty much the same as the symptoms of low testosterone:
- Lack of energy
- Lack of joie de vivre, in general
- Low or reduced sex drive
- Testicles the size of bing cherries (small)
- Inability to put on muscle or lose fat
- Sperm with no mojo
- Male breasts
- Lack of body hair
High SHBG can have far more serious health implications than those listed above, though, as they've also been linked to prostate cancer and Alzheimer's.
What Causes High SHBG Levels?
There are at least a couple of gene mutations that cause increased amounts of SHBG, which usually manifest themselves in the form of low sperm count or lousy sperm in general, but those are things you wouldn't normally be able to discern unless you were specifically chasing the causes of your infertility.
(Truth be told, there are also genetic mutations that lead to reduced SHBG levels, too, which often lead not only to increased levels of free testosterone, but a higher incidence of type 2 diabetes.)
Other, more likely things known to increase SHBG levels include:
- Alcohol – Drinking affects SHBG levels big-time, so much so that one study done in 1995 proposed that rapid rises in SHBG levels be regarded as a marker for alcoholism.
- Exercise – Weight training increases SHBG, but only temporarily. Training a lot without proper rest or nutrition (overtraining), though, causes a perpetual and probably detrimental rise in the binding protein.
- Various other hormonal imbalances – High thyroid and high estrogen can cause high SHBG levels, as can low growth hormone levels.
- Advancing Age – The older you get, generally speaking, the more SHBG you have to contend with.
- Excess fructose intake
What Can I Do to Lower SHBG Levels?
Plenty of things will reduce levels of SHBG. You could, for instance, just have a high-carb meal (assuming you're not somewhat insensitive to insulin). Insulin blocks SHBG.
Similarly, you could rub one out, as orgasms dull SHBG levels, but this remedy and the previous one are just temporary.
To have longer-lasting results, ones that might lead to actual changes in how you feel or how easily you put on muscle or lose fat, you need to adopt permanent lifestyle changes or start taking various supplements.
Most of you are already following a high-protein diet, so that's a big first step. You also need to make sure you're doing all the things you're supposed to do to build a healthy body in general, like getting enough sleep, eating the right foods, and not getting so stressed out that your go-to yoga pose is downward fetal-position dog.
But that's simpleton advice that applies to just about any health challenge presented by life. Assuming you're already doing all that, there are various supplements that have been shown in studies to reduce SHBG:
Making specific dosage recommendations is hard because SHBG levels and causes are highly individual and multifactorial. Following the general label instructions on the fish oil and tongkat ali (a Malaysian herb) is a viable approach, though. As far as the ZMA, vitamin D, boron, and calcium, it depends largely on whether you're deficient in any of them or not.
Obviously, if you're deficient, you need to at least get up to RDA-snuff by following the label recommendations. If you're not deficient in them, consider taking an extra capsule or tablet of any or each of the vitamins or minerals for their specific, "drug-like" effect of combating high SHBG.
Remember, SHBG is the Joker
You may have noticed that I've almost completely ignored inordinately low SHBG levels, which can cause its own problems, most of which are ones you'd typically associate with very high testosterone levels: increased muscle size, acne, baldness, increased aggression, and possibly even gynecomastia.
Reasons for low SHBG include a high testosterone level itself, high GH levels, fatty liver disease, perpetually high blood sugar levels, inflammation, and genetic mutations.
But telling someone they need to increase SBGH levels is a tough sell, because most people, regardless of their physiological state, want to decrease levels and free up all the testosterone they can. Still, low SHBG levels can lead to certain diseases like high blood pressure and heart disease.
You could raise levels to physiological norms, though, by eating more almonds and walnuts, cruciferous vegetables, coffee, and olive oil, in addition to doing more aerobic exercise, all of which is kind of a punch in the gut because they're things you're supposed to do anyhow if you want to be healthy.
That's probably another justifications for calling SHBG "the joker." My best advice is make any adjustments in diet, lifestyle, or supplement usage based on your symptoms or the results of an actual blood test ordered by your doc.
If you have symptoms of high SHBG (which correlate strongly with low levels of testosterone) or a blood test confirms it, follow the recommendations I've laid out for combating high SHBG levels.
If you have symptoms of low SHBG (which correlate strongly with high levels of testosterone), follow... oh, who are we kidding? We both know that if you have symptoms of low SHBG, you're going to ride that horse 'til it breaks.
Related: The Complete Guide to Testosterone Replacement
Related: The 3 Types of Testosterone Levels
- Chaoyang Li, MD, PHD,1 Earl S. Ford, MD, MPH,1 Benyi Li, MD, PHD,2 Wayne H. Giles, MD, MS,1 and Simin Liu, MD, SCD3, "Association of Testosterone and Sex Hormone-Binding Globulin With Metabolic Syndrome and Insulin Resistance in Men," Diabetes Care. 2010 Jul; 33(7): 1618-1624.
- Iturriaga H1, Valladares L, Hirsch S, Devoto E, P'erez C, Bunout D, Lioi X, Petermann M. "Effects of abstinence on sex hormone profile in alcoholic patients without liver failure," J Endocrinol Invest. 1995 Sep;18(8):638-44.
- Morgentaler, Abraham. "Testosterone for Life: Recharge Your Vitality, Sex Drive, Muscle Mass, and Overall Health," McGraw Hill, November 17, 2008.
- Selby C1. "Sex hormone binding globulin: origin, function and clinical significance," 1990 Nov;27 ( Pt 6):532-41.