# L-03 — Against the actives arms race

Ten percent niacinamide is not twice as good as five. The dose–response curve flattens and the complaint rate does not.

- **Canonical:** https://www.30plusskin.care/ledger/against-the-actives-arms-race
- **Site:** 30+/SKIN — Skincare, published as a spec sheet.
- **Issue:** ISSUE NO. 12 / REV. 2026.08
- **Standing terms:** INDEPENDENT · AFFILIATE-FUNDED · NOT MEDICAL ADVICE

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- **Published:** 2026-05-19
- **Reading time:** 5 min
- **Tags:** DOSE-RESPONSE, FORMULATION

Concentration is the easiest number to put on a bottle and the least informative one on it. It says nothing about pH, nothing about vehicle, nothing about whether the molecule reaches the layer it acts on.

> A 20% vitamin C at pH 4.2 is a 0% vitamin C with a marketing budget.

We compound to the middle of the published effective range, not the top of it. Where the curve flattens, the extra percent buys irritation and nothing else — and an irritated barrier is a barrier that absorbs unpredictably, which corrupts every other step.

| Field | Value |
| --- | --- |
| NIACINAMIDE, HOUSE | 5% |
| NIACINAMIDE, PUBLISHED RANGE | 2–10% |
| ASCORBIC ACID, HOUSE | 15% @ pH 3.0 |
| RETINAL, HOUSE | 0.10% |
| POSITION | MID-RANGE, NOT MAXIMUM |

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## Elsewhere in the register

- [Review register](/reviews)
- [Active monographs](/actives)
- [Brand register](/brands)
- [Evidence register](/evidence)
- [The ledger](/ledger)
- [How we test](/how-we-test)
- [Agent guide](/llms.txt)
- [Sitemap](/sitemap.xml)

_EVERY FIGURE RESOLVES TO A RECORD. NO NUMBER ON THIS SITE IS AUTHORED BY US._