What did @santacruzpaleo actually say?
The claim here is straightforward enough: the creator's testosterone went from 847 to 1,000 nanograms per deciliter, and he credits "blue light shit" for the jump. He mentions wearing blue light-blocking glasses at night, avoiding artificial light after dark, and getting morning sun exposure. He also references a podcast guest who apparently wears long sleeves at night to block light through skin, suggesting light receptors in the body beyond just the eyes play a role. The framing is personal testimony, not clinical data, and he acknowledges he is still doing lab work.
The transcript is fragmented and hard to parse in places, but the core argument is: circadian rhythm optimization, primarily through blue light reduction at night and sunlight in the morning, drove a meaningful increase in his total testosterone.
Does the science back this up?
Partially, yes. The connection between light exposure, circadian rhythm, and testosterone is real and documented, but the effect sizes seen in studies are modest compared to what this creator is implying.
Research does support the idea that circadian disruption suppresses testosterone. A study by Leproult and Van Cauter (2011, JAMA) found that sleep restriction to five hours per night for one week reduced testosterone levels in young healthy men by 10 to 15 percent. Sleep and circadian health are intertwined, and poor sleep is a well-established suppressor of androgen production.
On light exposure specifically, a 2021 study by Tähkämö et al. published in Sleep Medicine Reviews confirmed that evening blue light exposure delays melatonin onset and disrupts the sleep architecture that supports hormonal recovery. Testosterone secretion follows a circadian pattern, peaking during early morning sleep stages.
There is also some intriguing but preliminary work on extra-ocular photoreceptors, meaning light-sensitive receptors in the skin, but calling this settled science in 2024 would be a stretch. The claim that wearing long sleeves at night meaningfully changes testosterone through skin-based light blocking is not supported by robust human trials.
What did they get wrong (or right)?
They got the direction right. Light hygiene at night and morning sun exposure are legitimate tools for supporting sleep quality, which in turn supports testosterone production. That part is defensible.
Where this gets shaky is the implied causation. Going from 847 to 1,000 ng/dL is a 18 percent increase, and attributing that entirely to blue light blocking is a big leap. Total testosterone fluctuates naturally by 20 to 30 percent within a single day, let alone across different blood draws taken weeks or months apart. Mora-Rodriguez et al. (2022, Journal of Clinical Endocrinology and Metabolism) documented significant intra-individual variability in testosterone measurements, which means one higher reading does not confirm a real upward trend.
The claim about skin-based photoreceptors driving hormonal changes in humans is speculative at best. Studies on this topic, including work by Maguire et al. (2019), were conducted in fish and early animal models. Extrapolating that to humans wearing long sleeves is not science, it is pattern matching.
Credit where it is due: morning sunlight exposure to regulate circadian rhythm is genuinely supported. Eastman and Burgess (2009, PLOS Medicine) showed morning bright light exposure advances circadian phase and improves hormonal rhythms.
What should you actually know?
If your testosterone is clinically low, blue light glasses are not a treatment. They are a lifestyle optimization at best. A single lab result showing 1,000 ng/dL tells you almost nothing without knowing the time of day blood was drawn, whether it was a fasting sample, what the free testosterone and SHBG levels looked like, and how the number compares across multiple draws.
The 300 to 1,000 ng/dL reference range used by most labs is broad precisely because variability is real. A morning draw can read hundreds of points higher than an afternoon draw in the same person on the same day.
Light hygiene is a reasonable, low-risk practice. Wearing blue light-blocking glasses at night, dimming lights after sunset, and getting outdoor light in the morning are backed by enough sleep science to be worth doing. But if you are experiencing symptoms of low testosterone, including fatigue, low libido, or mood changes, that warrants a proper clinical evaluation, not a lifestyle experiment tracked by single data points posted to TikTok.
Telehealth platforms like FormBlends can connect you with licensed providers who order comprehensive hormone panels and interpret them in clinical context, not just total testosterone in isolation.