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The Apothecary Os

Acne / Pore Health

Comedogenicity Calculator

Weighted Fulton-scale score for a facial oil or moisturiser blend. On melanin-rich skin, clogged pores resolve as dark spots — keep the weighted score low and avoid rating-4+ ingredients in leave-on facial formulas.

Blend

R 2
R 0
R 1
R 0

Totals don't need to equal 100% — score is weighted by relative share.

Result

Weighted comedo score

1.00

Highest ingredient rating

2

Avg irritation index

0.00

Within safe range for acne skin.

Rules of thumb

  • Facial leave-on, acne-prone: keep weighted score < 1.5, no individual ingredient ≥ 4.
  • High-linoleic oils restore barrier in acne-prone skin (hemp, safflower-HL, sunflower-HL, grapeseed).
  • High-oleic oils (olive, marula, oleic safflower) can worsen acne via lipase activity from C. acnes.
  • Coconut oil & cocoa butter: body and hair only on acne-prone — never on facial leave-on.
  • Patch test: 2 weeks behind the ear, then jawline, before full face.
  • The Fulton scale is rabbit-ear based — treat as a guide, not gospel; individual response varies.