What did @onehottrail actually say?
The creator pushed back against a popular online claim that a thicker neck signals higher testosterone. Their core argument: "there's absolutely no evidence that a thicker neck is correlated with higher testosterone level." They went further, suggesting the opposite may be true, linking larger neck circumference to metabolic syndrome. They also called out a specific practice they see as dishonest: creators who post high total testosterone numbers without disclosing their free testosterone or sex hormone-binding globulin (SHBG) levels. The implication is that elevated SHBG can make impressive total testosterone numbers functionally meaningless.
This is a more nuanced take than most testosterone content on Instagram, and frankly, most of it holds up. But a few claims deserve closer scrutiny before you take them at face value.
Does the science back this up?
Mostly, yes. The neck-testosterone link is not supported by the literature, and the SHBG argument is clinically sound. Where things get shakier is in the creator's self-referential claims about their own testosterone levels.
On neck circumference: a 2014 study by Tsai et al. published in the Journal of Cardiovascular Endocrinology and Metabolism found neck circumference was positively associated with cardiometabolic risk factors including insulin resistance and dyslipidemia. A 2019 review in Obesity Reviews (Stabe et al.) confirmed neck circumference as a marker of visceral adiposity. Neither study links larger necks to higher testosterone. In fact, adipose tissue converts testosterone to estrogen via aromatase, so the metabolic syndrome angle the creator raises is directionally correct.
On SHBG and free testosterone: this is basic endocrinology. Free testosterone, roughly 1-3% of total testosterone, is the biologically active fraction. SHBG binds tightly to testosterone and renders it inactive. A man with a total testosterone of 900 ng/dL and an SHBG of 80 nmol/L may have less free testosterone than a man with 600 ng/dL total and an SHBG of 20 nmol/L. This is well-established in clinical literature, including the landmark work by Vermeulen et al. (1999, Journal of Clinical Endocrinology and Metabolism).
What did they get wrong (or right)?
They got the core science right, but the self-promotion muddies the water. Saying they have "some of the highest testosterone levels that I've seen in any natural" is unverifiable and irrelevant to the argument they were making. It adds nothing clinically and reads as the same kind of posturing they criticize others for.
The creator is also correct to flag that "high total testosterone means very little if they also have elevated SHBG." That is a genuine blind spot in how testosterone is discussed online. Posting a total T number without context is, at best, incomplete. At worst, it is misleading.
One thing they glossed over: SHBG is not always a villain. Higher SHBG can be associated with better cardiovascular outcomes in some populations (Westley et al., 2015, Journal of Clinical Endocrinology and Metabolism). Framing it purely as something that makes testosterone "mediocre" is a slight oversimplification, though not wrong in the context of symptom management for low-T.
The metabolic syndrome and erectile dysfunction connection to larger neck circumference is directionally supported by data, but the creator presents it with more certainty than the literature warrants. The association exists; causation is harder to establish.
What should you actually know?
If you are trying to assess your own testosterone status, a single number on a lab report is not enough. A complete picture requires total testosterone, free testosterone, SHBG, albumin, LH, FSH, and ideally estradiol. Without that panel, you are working with incomplete information, regardless of what any creator posts online.
Neck size tells you nothing reliable about your hormone levels. Body composition matters, but the relationship between adiposity and testosterone is complex. Excess body fat raises aromatase activity, which can lower testosterone and raise estrogen, but this varies significantly by individual.
The creator's point about selective disclosure is worth taking seriously. If someone's content revolves around their hormone levels, and they only ever show you one marker, ask why. Free testosterone and SHBG are not obscure tests. Any standard hormone panel includes them. Omitting them is a choice.
If you have symptoms that suggest low testosterone, including fatigue, reduced libido, difficulty maintaining muscle mass, or mood changes, the right move is a full lab panel interpreted by a clinician, not a neck flex test or an Instagram comparison.
Is this creator trustworthy on this topic?
More so than most in this space, with caveats. The debunking is grounded in real science, and the SHBG transparency argument is genuinely useful consumer education. The self-promotion is unnecessary and slightly undercuts the credibility of an otherwise reasonable take. Watch for the pattern they themselves identified: anyone, including this creator, who makes claims about their own hormone levels without showing a full panel should be viewed with appropriate skepticism.