@ryanskipslegs's testosterone concerns, fact-checked

What did @ryanskipslegs actually say?

Ryan says he spent years in an extreme caloric deficit chasing a shredded physique, at one point eating as few as "20 to 25 grams" of fat per day. He got his testosterone checked in 2023 and landed at 370 ng/dL total and around 11 pg/mL free testosterone. He now says he is 23, experiencing brain fog, and is finally getting retested to see if things have improved or worsened. He credits a "flush protocol" loosely described as Mediterranean-meets-carnivore for whatever recovery he may have achieved. He also makes the argument that bodybuilders can look muscular while still having suppressed testosterone because low body fat, not muscle, drives the problem.

He is not claiming to be on TRT and explicitly says he wants to avoid it. He is also upfront that he does not yet have his new results.

Does the science back this up?

Mostly, yes. The link between prolonged energy restriction, very low dietary fat, and suppressed testosterone is one of the more consistent findings in exercise endocrinology. Ryan is not wrong about the mechanism, even if he does not name it.

Research published by Hamalainen et al. (1984, Hormone and Metabolic Research) established early that low-fat diets reduce serum testosterone. More recently, Whittaker and Wu (2021, Journal of Steroid Biochemistry and Molecular Biology) conducted a systematic review and found that low-fat diets were associated with a statistically significant reduction in testosterone compared to high-fat diets. The effect size was modest but real. Fat is a precursor to cholesterol, which is the backbone of steroid hormone synthesis, so chronically restricting dietary fat does disrupt the hormonal supply chain.

The bodybuilding-specific data is also supportive. A 2021 study by Rossow et al. tracking natural bodybuilders during contest prep documented significant drops in testosterone as body fat declined. Some competitors did not fully recover after the competition ended. Ryan is describing this phenomenon accurately, even without citing the literature.

What did they get wrong (or right)?

Credit where it is due: the core claim holds up. Chronic severe caloric restriction combined with very low fat intake can suppress the hypothalamic-pituitary-gonadal axis. A total testosterone of 370 ng/dL at age 21 or 22 is genuinely on the low end. The Endocrine Society defines male hypogonadism as total testosterone below 300 ng/dL, but many clinicians treat symptoms in patients whose levels fall between 300 and 400 ng/dL, particularly when free testosterone is also low.

Where Ryan gets fuzzy is the "flush protocol" framing. There is no clinical literature supporting a named "flush protocol" combining Mediterranean and carnivore dietary patterns as a validated testosterone restoration strategy. These two diets have meaningfully different macronutrient philosophies. The Mediterranean diet is studied and has some hormonal data behind it. The carnivore diet does not have strong long-term testosterone data. He may have simply improved his fat intake and caloric balance, which would be sufficient to explain partial recovery. The label he puts on it is not backed by evidence.

He also does not mention sleep, stress, or zinc status, all of which are independently relevant to testosterone levels in young men.

What should you actually know?

If you have spent years in aggressive caloric restriction and are now experiencing symptoms like brain fog, low energy, or reduced libido, getting a full hormonal panel is a reasonable and low-risk step. That panel should include total testosterone, free testosterone, LH, FSH, SHBG, and ideally cortisol and thyroid markers. A single number without context is hard to interpret.

370 ng/dL with symptoms at age 23 is worth taking seriously, but it is not automatically a TRT indication. Lifestyle correction, specifically restoring adequate caloric intake, increasing dietary fat to at least 20 to 35 percent of total calories per dietary guidelines, prioritizing sleep, and managing chronic stress, has documented effects on testosterone recovery in young men. Cadet et al. (2020, Translational Andrology and Urology) noted that reversible secondary hypogonadism in young men is common and often lifestyle-driven.

TRT is a clinical decision made with a licensed provider based on labs, symptoms, and medical history. It is not something to jump into or avoid purely based on a TikTok narrative. If levels come back low again, that conversation belongs with a board-certified endocrinologist or urologist, not a social media comment section.