Recovery
Perineum Sunning
No tissue absorbs sunlight in a special way. You are applying UV to some of the thinnest, least-protected skin on the body.
Also called: butthole sunning · perineum sunbathing
Verdict — cope
The mechanism does not hold. Your time is better spent elsewhere.
Evidence grade D
Nobody has demonstrated this works. Note that this grades the evidence, not the danger — read the verdict for that.
Mechanism
Vitamin D synthesis from UVB is proportional to exposed surface area and skin melanin, not to site. The perineum offers a trivial fraction of body surface and has minimal melanin protection.
Citations
- Cutaneous vitamin D synthesis: dependence on surface area, wavelength and skin typeJournal of Investigative Dermatology · 2010
The full read
The claim — that perineal exposure delivers a uniquely potent dose of energy or vitamin D — has no proposed pathway and no data. Cutaneous vitamin D synthesis is an area-and-wavelength story, so thirty seconds of perineal exposure is worth a rounding error against forearms at midday. Meanwhile thin, chronically covered, unmelanised skin burns fast, and genital-site skin cancers are disproportionately aggressive when they occur. Twenty minutes of forearms, or a €5 D3 bottle (`vitamin-d`), does the job.
