Cell membranes throughout your body — including the ones that form your skin barrier — are built partly from the fatty acids you consume. The internal oil contributes to that process from within, influencing membrane composition over weeks of consistent daily intake.

The skin barrier is also shaped by what you apply directly to it. The topical oil works at the surface — contributing fatty acids to the lipid matrix that holds skin cells together and determines how well the barrier retains moisture and resists disruption.

One works from the inside out. The other works from the outside in. They are addressing the same underlying biology from opposite directions and on different timescales. That is why they exist as a pair.