SHBG and testosterone in women: what the science actually supports

What did @michelehormonehealth actually say?

The core claim here is straightforward: if your total testosterone looks normal but you still feel terrible, high SHBG could be binding up your testosterone and leaving you with very little free, active hormone. She lists fatigue, low libido, and brain fog as symptoms, and suggests looking at carbs, protein, delivery route, insulin patterns, thyroid, and dosing as potential levers.

She also makes a pointed clinical argument: "checking total testosterone alone misses the full picture." That's not fringe thinking. It's a real debate that's been simmering in endocrinology for over a decade. She's not selling a quick fix here. She's pointing at a mechanism and suggesting it warrants investigation. That's a reasonable starting point, even if some of the details deserve scrutiny.

Does the science back this up?

Mostly, yes. SHBG absolutely binds testosterone, and high SHBG does reduce free testosterone availability. This is not controversial. The question is whether free testosterone measurements actually predict symptoms better than total testosterone. The evidence is more complicated than the video suggests.

A 2019 analysis by Handelsman in the Journal of Clinical Endocrinology and Metabolism argued that calculated free testosterone has serious methodological limitations, including errors introduced by albumin assumptions and assay variability. The equilibrium dialysis method for measuring free testosterone is considered most accurate but is rarely done in clinical practice. Meanwhile, a 2020 study by Davis and colleagues in Menopause found that free androgen index and calculated free testosterone correlated modestly with sexual function outcomes in perimenopausal women, but the associations were not strong enough to make free testosterone a reliable standalone diagnostic tool.

So yes, SHBG matters. But "what matters is what's free" is a bit cleaner than the actual evidence warrants.

What did they get wrong (or right)?

She gets the mechanism right. High SHBG reduces bioavailable testosterone. That's solid biochemistry. She also gets credit for flagging oral delivery as a potential SHBG-raising route. Oral testosterone and oral estrogen are both known to increase hepatic SHBG production through first-pass liver metabolism. That's a real clinical consideration backed by pharmacokinetic data.

Where she oversimplifies: the claim that symptoms like brain fog and low libido are explained by high SHBG is presented as more direct than the evidence supports. These symptoms are nonspecific and overlap with thyroid dysfunction, depression, sleep disorders, and perimenopause itself. Attributing poor therapy response primarily to SHBG without ruling out other causes is a shortcut that could mislead viewers.

The nutrition advice, specifically "enough carbs and protein," is genuinely interesting. There is some evidence that low-carbohydrate diets raise SHBG, with a frequently cited study by Longcope and colleagues in the American Journal of Clinical Nutrition (2000) showing dietary fiber and fat intake influenced SHBG levels. But the effect sizes are modest, and framing macronutrient intake as a primary SHBG intervention oversells the data.

She also mentions insulin patterns and thyroid function as SHBG modulators. Both are legitimate. Insulin resistance suppresses SHBG, and hypothyroidism lowers it. Hyperthyroidism raises it. These are accurate associations, though they're stated without much nuance.

What should you actually know?

If you're on testosterone therapy and still feel off, SHBG is worth checking. But it's one variable in a panel that should also include free testosterone via equilibrium dialysis if possible, thyroid function, cortisol, iron studies, and a honest assessment of sleep quality and mental health.

The bigger issue the video doesn't address is that "optimal" free testosterone ranges for women are not well established. Reference ranges vary significantly by lab, and there's no agreed threshold at which free testosterone reliably improves symptoms. A 2021 review by Islam and colleagues in the Journal of Clinical Endocrinology and Metabolism noted that defining androgen deficiency in women remains hampered by lack of standardized assays and population-based normative data.

If your provider is only running total testosterone and calling it a day, this video gives you a reasonable prompt to ask for a more complete panel. That's genuinely useful. But don't walk away thinking high SHBG is definitively why you feel bad. It might be part of the story. It's rarely the whole one.