Meta Information
ID:retinol-otc
Name:Retinol (OTC)
Schema Version:2.4_uniform_evidence_2026_06_18
Created
2026-07-02T07:35:59Z
Model
phase-b-topical-claude-opus-4.8
Interactions
Target id:
/class/retinoids
Target name:
Topical retinoids (tretinoin, retinol, adapalene)
Severity:
moderate
Interaction type:
adverse
Nature:
relative
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Layering retinol with a retinoid in the same routine can over-irritate the skin (redness, peeling, barrier damage).
Actionable advice:
These are best used on alternate nights or at different times of day, with moisturizing and gradual introduction.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Stacking multiple keratolytic/irritant actives compounds barrier disruption; standard dermatologic practice is to separate or alternate.
Label source:
Class inference
Action type:
separate
Target id:
/class/exfoliating-acids
Target name:
Other exfoliating acids (AHAs/BHAs)
Severity:
moderate
Interaction type:
adverse
Nature:
relative
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Combining retinol with other exfoliating acids can over-exfoliate, causing irritation, redness, and a compromised skin barrier.
Actionable advice:
Stacking multiple acids in one routine is best avoided; alternating days and monitoring for irritation is preferable.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Additive keratolysis from stacked acids -> over-exfoliation. Dermatologic practice.
Label source:
Class inference
Action type:
separate
Target id:
/intervention/sunscreen
Target name:
Sun exposure / sunscreen
Severity:
moderate
Interaction type:
requirement
Nature:
relative
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
retinol can increase the skin's sensitivity to UV light, raising the risk of sunburn and photodamage.
Actionable advice:
Daily broad-spectrum sunscreen is best used, with the active applied at night.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Exfoliants/retinoids thin the stratum corneum and increase photosensitivity; daily sunscreen is required. Dermatologic consensus.
Label source:
Class inference
Action type:
monitor
Target id:
/condition/sensitive-skin-rosacea
Target name:
Sensitive skin / rosacea
Severity:
moderate
Interaction type:
adverse
Nature:
conditional
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
retinol can sting and worsen redness in sensitive or rosacea-prone skin.
Actionable advice:
Patch-test, use lower strength/frequency, and buffer with moisturizer if you have sensitive or rosacea-prone skin.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Low-pH/irritant actives provoke stinging and flares in sensitive/rosacea skin. Dermatologic practice.
Label source:
Class inference
Action type:
monitor
Target id:
/intervention/benzoyl-peroxide
Target name:
Benzoyl peroxide
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Benzoyl peroxide is a strong oxidizer that can degrade retinol applied at the same time, reducing its effect.
Actionable advice:
Benzoyl peroxide is best used in the morning and retinol at night (older formulations); many modern retinoids are more stable.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Oxidative degradation of retinoids by benzoyl peroxide when co-applied; separate timing. Dermatologic practice.
Label source:
Class inference
Action type:
separate
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
moderate
Interaction type:
adverse
Nature:
conditional
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Topical retinoids are generally avoided in pregnancy as a precaution, despite low systemic absorption.
Actionable advice:
Topical retinoids (including OTC retinol) are best avoided during pregnancy and while trying to conceive.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / dermatologic practice (no single primary source quoted)
Exact phrase from label:
Systemic absorption of topical retinoids is low, but they are precautionarily avoided in pregnancy given oral-retinoid teratogenicity. Standard obstetric/derm guidance.
Label source:
Class inference
Action type:
avoid