Skip to main content
The Apothecary Os

Surfactant Formulation

Cleanser Mildness Index

Weighted active matter, mildness, foam, and charge balance for cleansing blends — tuned for the pH-sensitive acid mantle of melanin-rich skin.

Product target

Target active matter 814% · minimum mildness 4.5/5. Keep pH 4.5–5.5. Avoid SCS/SLES alone.

Surfactant blend

% is the supplied material in the finished product (not active matter).

→ 7.5% act
→ 5.0% act
→ 2.4% act

Results

Active matter

14.9 %

Mildness (1–5)

4.84

Foam (1–5)

3.66

Anionic share

50 %

Active matter out of range for face cleanser (sensitive / melanin-rich). Aim 814%. Currently 14.9%.

Anionic

7.5%

Amphoteric

2.4%

Nonionic

5.0%

Formulation rules

  • Active matter drives cleansing power AND dryness — stay inside the target range.
  • Mildness ≥ 4.5 for facial, scalp-sensitive, and intimate washes.
  • CAPB / Coco Sultaine at 15–30% of total active reduces irritation of anionic primaries.
  • Cationic conditioners (Polyquats, BTMS) precipitate with anionic surfactants — keep in conditioner, not shampoo.
  • pH 4.5–5.5 for skin and scalp; intimate wash 4.0–4.5. Adjust with citric acid post-cool.
  • Glucosides raise pH — buffer down with lactic or citric acid.
  • Syndet bars need ≥50% active matter (SCI-dominant) to hold shape.