@shreddedsages's testosterone boosting claims, fact-checked

What does this video actually claim?

Nathan Sages makes three specific claims about boosting testosterone: boron supplementation reduces SHBG and increases free testosterone, training in the 4-6 rep range activates androgen receptors better than other rep ranges, and sprinting increases both total testosterone and growth hormone while specifically boosting free testosterone.

These aren't uncommon claims in the testosterone optimization space. But each one needs scrutiny because the evidence behind them varies wildly.

Does boron supplementation actually work?

There's limited but promising data on boron. The strongest study comes from Naghii et al. (2011) in the Journal of Trace Elements, where 10mg daily boron for one week increased free testosterone by 28.3% and reduced SHBG by 9% in healthy men.

That sounds impressive until you notice the sample size: just 8 men. A later study by Miljkovic et al. (2004) found no testosterone changes with boron in 18 bodybuilders over 7 weeks.

The deficiency angle is questionable too. Most Americans get 1-3mg of boron daily from food, and there's no established requirement. Calling widespread deficiency a problem overstates the evidence.

What about heavy training and rep ranges?

This claim is mostly wrong. Sages suggests that 4-6 reps specifically activate androgen receptors better, but that's not how androgen receptors work.

The Kraemer and Ratamess (2005) review in Sports Medicine shows that both heavy (1-6 reps) and moderate (6-12 reps) training increase testosterone acutely. The difference? Heavy training causes bigger immediate spikes, but moderate training produces more sustained elevations.

More importantly, these exercise-induced testosterone changes don't translate to meaningful long-term increases. Hackney et al. (2003) found that chronic heavy training can actually suppress resting testosterone levels in some athletes.

Does sprinting boost testosterone and growth hormone?

This one's accurate. Stokes et al. (2013) in the European Journal of Applied Physiology found that repeated 6-second sprints increased testosterone by 27% and growth hormone by 530% immediately post-exercise in trained men.

However, Sages doesn't mention that these are acute changes lasting hours, not permanent increases. The Boutcher (2011) review in Journal of Obesity shows HIIT improves body composition and insulin sensitivity, but evidence for lasting hormonal changes is thin.

The free testosterone claim is harder to verify since most sprint studies only measure total testosterone.

What should you actually know about testosterone optimization?

Natural testosterone optimization has real limits. Sleep quality, body weight, and stress management matter more than any of these three tactics.

Leproult and Van Cauter (2011) showed that one week of 5-hour sleep reduced testosterone by 15% in healthy young men. That's a bigger effect than most supplements claim.

If your testosterone is clinically low (under 300 ng/dL), lifestyle changes won't fix it. You need medical evaluation and possibly TRT. If it's normal, chasing marginal gains through supplements and specific rep ranges probably won't change how you look or feel.