PCOS, testosterone, and SHBG: separating signal from noise

What did @polybiotics actually say?

The claim is straightforward: you can have PCOS even if your total testosterone comes back normal on a lab report. The reason, according to the creator, is that low SHBG (sex hormone binding globulin) allows more testosterone to roam free in the bloodstream, creating what they call a "high androgen index." They describe this free testosterone as being "able to recover with your body" and list hair thinning, excess body hair, and acne as the resulting symptoms. The video is responding to a common question from followers who got a normal testosterone result and wondered if PCOS was still possible.

This is a legitimate clinical concept being explained for a lay audience, and the core message is medically defensible. The framing is simplified, but simplification is not the same as misinformation.

Does the science back this up?

Yes, mostly. The relationship between SHBG, free testosterone, and PCOS symptoms is well-established in endocrinology research. A 2010 review by Goodman et al. in Fertility and Sterility confirmed that free androgen index (FAI), calculated from total testosterone and SHBG, is a reliable marker of androgen excess in women with PCOS, often more clinically relevant than total testosterone alone.

A 2018 study by Lizneva et al. in the Journal of Clinical Endocrinology and Metabolism found that a meaningful proportion of women with PCOS who would be missed by total testosterone cutoffs were identified when free androgen markers were used. SHBG is also suppressed by insulin resistance, which is common in PCOS, creating a feedback loop that worsens androgen exposure even when total testosterone stays within reference range.

The symptoms listed, specifically hirsutism, androgenic alopecia, and acne, are well-documented features of hyperandrogenism in PCOS, as outlined in the 2023 international evidence-based PCOS guidelines published across multiple journals including Human Reproduction Update.

What did they get wrong (or right)?

The creator deserves credit for the overall message. Normal total testosterone does not rule out PCOS, and this is genuinely something many clinicians miss. But the phrasing "able to recover with your body" is awkward and unclear. They likely meant "interact with" or "act on" receptors in body tissues. That kind of verbal slip in a fast-paced video is forgivable, but it could confuse viewers who take the wording literally.

The term "high androgen index" is used loosely. The actual clinical term is free androgen index (FAI), calculated as total testosterone divided by SHBG, multiplied by 100. This is not a minor distinction when someone is trying to interpret their own labs. Viewers may search "androgen index" and not find useful results because the standard term is different.

One gap worth flagging: the video does not mention that SHBG can be low for reasons unrelated to PCOS, including obesity, hypothyroidism, and type 2 diabetes. Low SHBG and elevated FAI are not diagnostic of PCOS on their own. The creator implies a tighter causal link than the evidence actually supports.

What should you actually know?

If you have PCOS symptoms but a normal total testosterone, the next reasonable step is asking your provider to check SHBG and calculate your free androgen index. This is standard practice according to the 2023 international PCOS guidelines, yet it is still frequently skipped in primary care settings.

However, PCOS is a diagnosis of exclusion. Elevated free androgens explain symptoms, but you still need other criteria met under the Rotterdam criteria, specifically two of three: irregular ovulation, polycystic ovarian morphology on ultrasound, or clinical or biochemical hyperandrogenism. A low SHBG reading alone does not equal a PCOS diagnosis.

• Always ask for SHBG alongside total testosterone, not just one or the other.
• Free androgen index above 4-5 is generally considered elevated in women, though reference ranges vary by lab.
• Insulin resistance can suppress SHBG independently, so metabolic workup matters here too.
• Hair thinning in PCOS is typically androgenic alopecia, which responds differently to treatment than other hair loss types.

Bottom line: should you trust this video?

For a 13.5K-view TikTok on a genuinely misunderstood endocrine topic, this is more accurate than most. The creator is not selling anything in this clip and the core science holds up. The weak spots are terminology precision and the missing caveat that low SHBG is not exclusive to PCOS. Take this as a prompt to have a real conversation with a clinician, not as a substitute for one.