Squalane, the stabilized form of an oil the skin already makes, is a light, well-tolerated softening oil that slows water loss. Only ingested squalene has been tested in a controlled human study: smoother skin at very high doses, alongside frequent loose stool and darker facial pigment. The applied oil alone has never been compared against a blank cream. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Sebum output, forehead (instrumental) | 100–200 µg/cm² | Identifies the surface lipid deficit squalane is meant to fill |
| Transepidermal water loss | Under 15 g/m²/h on the face | Direct read of barrier integrity and the endpoint occlusive lipids move |
| Outer-layer water content (corneometry) | Above 45 arbitrary units on the cheek | Tracks whether added lipid is holding water in the outer layer |
| Skin surface squalene peroxide | No established target; track change from the individual's own baseline | Flags the oxidized fraction that drives pore blockage and roughening |
| Serum squalene | No established target; track change from the individual's own baseline | Confirms absorption during oral use and nothing more |
| Serum lipid panel | Low-density lipoprotein cholesterol under 100 mg/dL; triglycerides under 100 mg/dL | Gram-level squalene feeds the cholesterol pathway, so lipids warrant watching |
| Serum retinol | 1.05–2.45 µmol/L | Detects vitamin A accumulation from shark liver oil-sourced squalene |
Cadence: Baseline before starting, then instrumental skin measurements at 4 weeks and 12 weeks and every 6 months while use continues. For oral use: bowel habit weekly through the first month, with serum lipids and retinol at 3 months and then annually.