SHBG & Testosterone: The Hidden Factor Sabotaging Your Results

You’re eating clean. You’re training hard. Your testosterone levels came back “normal”. But something still isn’t clicking. Low energy, poor recovery, stubborn fat, and that frustrating sense that your body just isn’t responding.

What if the problem isn’t your testosterone… but what’s blocking it?

Let’s talk about SHBG, the underdog hormone regulator that might be quietly sabotaging your results.

What Is SHBG?

SHBG stands for Sex Hormone-Binding Globulin, a protein produced in the liver. Its main job? To bind to sex hormones like testosterone and estrogen and carry them through your bloodstream.

But here’s the twist: when testosterone is bound to SHBG, it becomes inactive. That means your body can’t actually use it to build muscle, boost libido, regulate mood, or power your performance.

Think of SHBG like a taxicab service: it picks up testosterone and drives it around… but it doesn’t let it off the ride. Only the “free” testosterone, that is, unbound, is available to actually do the work.

Free vs. Total Testosterone—Why the Difference Matters

If you’ve ever had your testosterone tested and been told it’s “in range,” there’s a good chance that test only measured total testosterone, which includes both free and bound.

But here’s the issue:🔒 SHBG binds testosterone →📉 Free testosterone drops →😫 You feel low energy, poor recovery, less drive

High SHBG levels can make you feel testosterone-deficient even if your total T looks fine on paper.

According to a review in the Journal of Clinical Endocrinology & Metabolism, only about 2–3% of circulating testosterone is free and biologically active, the rest is bound to SHBG or albumin [1].

So if your SHBG is high, your usable testosterone may be way too low, even while your “official” test says you’re fine.

What Affects SHBG Levels?

SHBG isn’t a fixed number, it’s influenced by several lifestyle, health, and metabolic factors:

• Liver function: SHBG is produced in the liver. Poor liver health = skewed SHBG levels.

• Thyroid hormones: Hyperthyroidism raises SHBG, while hypothyroidism can lower it [2].

• Insulin resistance & obesity: These often reduce SHBG levels, but not always in a helpful way [3].

• Age: SHBG increases naturally with age, which contributes to lower free T in older men [4].

• Nutrition: High-fiber diets and certain micronutrients can increase SHBG; excess sugar may lower it.

• Steroid use or suppression: AAS or testosterone therapy can disrupt SHBG production dramatically.

• Exercise & stress: Chronic overtraining or prolonged stress may dysregulate SHBG indirectly.

This makes SHBG a highly individualized marker, and a crucial piece of the hormonal puzzle.

How High or Low Is Too Much?

Normal SHBG ranges vary by lab, but for men, it typically falls between 10–57 nmol/L. However, what's “normal” on paper isn’t always optimal in practice.

🧬 High SHBG (> 60–70 nmol/L): May reduce free T dramatically; Can be caused by hyperthyroidism, under-eating, liver issues, certain meds

🧬 Low SHBG (< 10–15 nmol/L): Can indicate insulin resistance or metabolic dysfunction; Also leads to hormonal imbalances, just in a different way

The sweet spot is individualized, but that’s the point: test, track, adjust.

Symptoms of High SHBG & Low Free Testosterone

If your SHBG is too high, you might experience:

• Constant fatigue

• Slower recovery after training

• Decreased libido or sexual performance

• Loss of muscle mass or difficulty building it

• Mood instability, anxiety, or low motivation

• Increased belly fat or overall poor body comp

  
  

And the kicker? Your doctor might look at your total testosterone and say “you’re fine. ”Meanwhile, your free T is tanking, and your body knows it.

How Do You Test for SHBG?

If you're serious about understanding your hormones, you can’t rely on total testosterone alone. You need a full hormone panel that includes:

✅ Total Testosterone ✅ Free Testosterone (preferably calculated)

✅ SHBG

✅ Albumin

✅ Estradiol (E2)

✅ LH/FSH

✅ TSH (thyroid function)

Most comprehensive panels will also calculate your Free Androgen Index (FAI), a ratio of total T to SHBG that gives further insight into your actual usable testosterone levels.

If your SHBG is high and your free T is low, you’ve just found your missing link.

What Can You Do About It?

Here’s the good news: SHBG levels can be influenced. It’s not about hacking, it’s about optimizing.

🧠 Support your liver: Prioritize sleep, hydration, and reduce alcohol; Consider supplements like NAC or milk thistle (check with your practitioner)

🥦 Balance your nutrition: Avoid chronically low-calorie diets; Optimize micronutrients, especially magnesium, zinc, vitamin D

🏋️‍♂️ Train smart, not just hard: Avoid overtraining; Respect rest days; Don’t combine high-volume training with under-fueling

🧘 Manage insulin & inflammation: Reduce sugar intake; Increase fiber; Stay active, manage stress levels

🧑‍⚕️ Work with a coach or clinician: Test frequently; Monitor trends, not snapshots; Adjust training, nutrition, and lifestyle to support hormonal balance

Why This Matters More Than Ever

In the world of high-performance training, testosterone gets all the attention, but SHBG is the gatekeeper.

You could be doing everything “right,” yet spinning your wheels because your free testosterone is locked away by high SHBG.

It’s not just about pushing harder. It’s about being smarter, knowing your numbers, understanding your body, and optimizing your internal environment.

That’s how you unlock real change.

Conclusion: Know Your Numbers. Know Your Power.

SHBG may not be a buzzword in the gym... yet. But it should be.

If you’ve hit a wall with your training, feel like your fire is dimming, or just want to optimize your health from the inside out, this is your call to action.

📉 Don't settle for "normal."

🔬 Go deeper. Get educated.

🦁 Take control.

🔗 Ready to Optimize?

Want help interpreting your SHBG levels and unlocking real performance results? Book a 1-on-1 consult or explore our Elite Hormonal Optimization Coaching at 👉 www.physiondynamics.com

📚 References:

1. Handelsman, D.J. (2017). "Testosterone and Male Reproductive Health." The Journal of Clinical Endocrinology & Metabolism, 102(10), 3459–3460.

2. Longcope, C. (2000). "Influence of aging on sex hormones in men and women." The Journal of Clinical Endocrinology & Metabolism, 85(4), 1641–1655.

3. Ding, E.L., Song, Y., Malik, V.S., Liu, S. (2006). "Sex hormone-binding globulin and risk of type 2 diabetes in women and men." New England Journal of Medicine, 354(6), 557–566.

4. Vermeulen, A. et al. (1999). "A critical evaluation of simple methods for the estimation of free testosterone in serum." The Journal of Clinical Endocrinology & Metabolism, 84(10), 3666–3672.