Journal · Clinical reading · 5 min
The tolerance ceiling: why higher stops helping.
Every active has a curve. Below the first threshold nothing happens. Above the second threshold, tolerance collapses. The best formulas sit in the middle.
The Biomedical Emporium® formulation desk
3 March 2026
Take vitamin C at ascorbic acid form. Below 8%, the antioxidant benefit is thin. Between 10% and 15%, you see the clinical work everyone talks about. Above 20%, tolerance falls off a cliff and stability plummets. Formulators know this. Marketing sometimes ignores it.
This pattern repeats across most actives worth using. There is a curve, there are two thresholds on it, and the interesting territory is between them. If a brand only ever advertises the top of the curve, it is selling a marketing claim, not a clinical protocol.
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Vitamin C: the four forms and where each belongs.
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