What did @juliosantosdesoto actually say?
The creator describes developing alopecia areata at 22, discovering his testosterone levels were "that of a 70 to 80 year old man," and connecting the dots between years of maintaining very low body fat for modeling and elevated cortisol from chronic undereating. His fix: stop living in a caloric deficit, eat at maintenance or a surplus, and let the hair grow back. That's the whole argument, and it's more coherent than most TikTok health advice.
To be clear, he's not claiming TRT fixed him. He actually declined TRT and chose to change his diet instead. He says "that's it" when describing eating more as his solution. He's making a nutritional and hormonal case, not a supplement pitch.
Does the science back this up?
More than you'd expect from a 927K-view TikTok. The link between chronic energy restriction, elevated cortisol, and suppressed testosterone is real and reasonably well-established. The leap to alopecia areata is more complicated, but not baseless.
Prolonged caloric restriction reliably suppresses the hypothalamic-pituitary-gonadal (HPG) axis. Leproult and Van Cauter (2011, JAMA) found that even one week of sleep restriction (a stressor with cortisol overlap) reduced testosterone by 10-15%. More directly, studies on competitive athletes and military personnel in sustained energy deficits consistently show suppressed LH, FSH, and testosterone. Kyrolainen et al. (2008, Medicine and Science in Sports and Exercise) documented significant testosterone suppression in soldiers during prolonged field exercises with caloric restriction.
On alopecia areata specifically: the condition is autoimmune, not simply stress-driven. But there's emerging evidence that cortisol dysregulation and HPA axis dysfunction can modulate immune activity in ways that trigger or worsen autoimmune hair loss. Gilhar et al. (2012, New England Journal of Medicine) established the autoimmune basis clearly. The stress-cortisol-immune connection is plausible but far from a clean causal chain.
What did they get wrong, and what did they get right?
He got the core hormonal physiology roughly right. The part about alopecia areata being "caused by stress" is where things get oversimplified, and his dermatologist probably deserves some of the blame for that framing.
What he got right: chronic undereating at very low body fat percentages (he mentions hovering under 7%) is a genuine physiological stressor. It elevates cortisol. Elevated cortisol suppresses testosterone through well-documented mechanisms. This is not bro-science; it's endocrinology. Giving credit where it's due, the guy read the situation correctly and chose a dietary intervention over hormone therapy at 22, which is a reasonable call if the underlying cause is nutritional.
What he got wrong, or at least oversimplified: alopecia areata is an autoimmune condition where T-cells attack hair follicles. Saying it was "caused by stress" flattens a complicated disease. Many people with alopecia areata have no identifiable cortisol or testosterone issue. His case may represent a genuine nutritional trigger, but framing this as a universal explanation for the condition would mislead the large number of viewers who have alopecia areata with no hormonal component. The mechanism he's describing is plausible for his specific case. It is not a general cure framework.
What should you actually know?
If you have alopecia areata, this video is interesting but it is not your treatment plan. The condition has multiple subtypes and triggers, and most cases require evaluation by a dermatologist, not a calorie adjustment.
That said, if you are a male maintaining extremely low body fat for extended periods and experiencing fatigue, low libido, or hair changes, getting a testosterone panel is genuinely reasonable. Functional hypogonadism from energy restriction is underdiagnosed. A 2021 review by Jayasena et al. in Clinical Endocrinology found that reversible causes of low testosterone, including nutritional status, are frequently overlooked before TRT is initiated.
- Alopecia areata affects roughly 2% of the population and is classified as an autoimmune disease, not a stress disease, though stress can be a trigger in susceptible individuals.
- Corticosteroid injections, which he received, are a legitimate first-line treatment. His description of them as "not a long-term solution" is accurate; they treat flares, not the underlying autoimmune process.
- Declining TRT at 22 to first investigate reversible causes is clinically defensible and often the right call. TRT suppresses endogenous testosterone production, which matters more in younger patients.
- Eating at 7% body fat continuously is not sustainable and is below the range most sports medicine physicians consider safe for long-term male hormonal health.
Bottom line
This is a personal anecdote that happens to align with real physiology. The hormonal mechanism he describes is supported by evidence. The leap to alopecia areata as a cortisol-driven condition is plausible but oversimplified. Do not take one model's hair recovery story as a treatment protocol for an autoimmune condition. Do talk to a doctor if you are chronically undereating and experiencing hormonal symptoms.