Serum Facial Rn-0,3

Principia

Where to buy Possibly in stock

About this product

The Principia Serum Facial Rn-0,3 is a emulsion. Our analysis of its 19 ingredients (12 low-risk) rates it Excellent (92/100). Based on its ingredients, it looks well-suited to oily / acne-prone and dry skin.

Vegan-friendly Reef-safe

Summarised from our ingredient analysis — not brand marketing copy.

At a glance

Type
Emulsion
Ingredients
19
Low-risk
12
Fragrance
Fragrance-free
Origin
Brazil

The evidence

Quick Product Notes

Paraben-Free Sulfate-Free Alcohol-Free Silicone-Free EU Allergen-Free Fungal Acne (Malassezia) Safe

Notable Effects & Ingredients

No Notable Effects & Ingredients

Ingredients Related to Skin Types

Good   Bad — tap a skin type to see which ingredients · estimated from ingredient functions
Dry Skin 3/2
Good for dry skin
Undecane Caprylyl Glycol Coco-Caprylate/Caprate
Caution for dry skin
Potassium Cetyl Phosphate Sodium Hydroxide
Oily/Acne-Prone Skin 1/0
Good for oily/acne-prone skin
Retinol
Sensitive Skin 2/3
Good for sensitive skin
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate Tocopheryl Acetate
Caution for sensitive skin
Tridecane Phenoxyethanol Retinol

Ingredients list

19 total
Lower hazard (1) Higher hazard (9)
All19 Skin Conditioning12 Viscosity Controlling3 Fragrance3 Antioxidant3 Emollient3 Solvent2 Chelating2 Humectant1
EWG CIR Ingredient Name & Cosmetic Functions Notes
1
Water
(Solvent)
1
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
(Emulsion Stabilising, Film Forming, Viscosity Controlling)
3
B
Sodium Hydroxide
(Denaturant, Ph Adjuster, Buffering Agent)
1
A
Sodium Gluconate
(Chelating Agent, Skin Conditioning)
1
Propanediol
(Solvent, Viscosity Decreasing Agent, Viscosity Controlling)
1
B
Potassium Cetyl Phosphate
(Emulsifying, Surfactant)
Hydrogenated Palm Glycerides
(Skin Conditioning, Skin Conditioning Emollient, Surfactant Emulsifying, Viscosity Controlling)
1
B
Coco-Caprylate/Caprate
(Emollient, Skin Conditioning)
3
Tocopheryl Acetate
(Antioxidant, Skin Conditioning)
Bad for Oily Skin
Bad for Oily Skin
1
A
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
(Antioxidant)
9
A
Retinol
(Skin Conditioning)
Bad for Sensitive Skin
Bad for Sensitive Skin
1
Undecane
(Emollient, Skin Conditioning)
1
Tridecane
(Perfuming)
TOCOPHEROL
(Antioxidant, Fragrance, Skin Conditioning)
Sodium Diethylenetriamine Pentamethylene Phosphonate
(Chelating)
Sodium Gluceptate
(Chelating)
Bisabolol
(Fragrance, Skin Conditioning, Soothing)
4
A
Phenoxyethanol
(Fragrance, Preservative)
Paraben
Paraben
1
A
Caprylyl Glycol
(Hair Conditioning, Skin Conditioning, Emollient, Humectant)

My Ingredient Notes

No personal ingredient notes yet. Save ingredients to your profile to get good/bad alerts here.

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Key ingredients

Sodium Gluconate
Skin Conditioning
Hydrogenated Palm Glycerides
Skin Conditioning
Coco-Caprylate/Caprate
Emollient, Skin Conditioning
Tocopheryl Acetate
Antioxidant, Skin Conditioning
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
Antioxidant
Retinol
Skin Conditioning

Benefits

Fungal-acne (Malassezia) safe
Good for dry skin
Good for oily/acne-prone skin

Concerns

Contains paraben
Retinol — higher EWG
May not suit sensitive skin

EWG flags hazard, not real-world risk — ratings don't account for how much of an ingredient a product contains. Treat these as things to research, not verdicts. How we score →

Ingredients explained

Water
Solvent
Low-hazard ingredient.Read moreShow less
EWG 1 Solvent
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
Emulsion stabilising, Film forming
Low-hazard ingredient.Read moreShow less
EWG 1 Emulsion stabilisingFilm formingViscosity controlling
Sodium Hydroxide
Denaturant, Ph adjuster
Low-to-moderate hazard.Read moreShow less
EWG 3 CIR B DenaturantPh adjusterBuffering agent
Sodium Gluconate
Chelating agent, Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 CIR A Chelating agentSkin conditioning
Propanediol
Solvent, Viscosity decreasing agent
Low-hazard ingredient.Read moreShow less
EWG 1 SolventViscosity decreasing agentViscosity controlling
Potassium Cetyl Phosphate
Emulsifying, Surfactant
Low-hazard ingredient.Read moreShow less
EWG 1 CIR B EmulsifyingSurfactant
Hydrogenated Palm Glycerides
Skin conditioning, Skin conditioning emollient
Limited public safety data.Read moreShow less
EWG N/A Skin conditioningSkin conditioning emollientSurfactant emulsifyingViscosity controlling
Coco-Caprylate/Caprate
Emollient, Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 CIR B EmollientSkin conditioning
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
Antioxidant
Low-hazard ingredient.Read moreShow less
EWG 1 CIR A Antioxidant
Undecane
Emollient, Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 EmollientSkin conditioning
Tridecane
Perfuming
Low-hazard ingredient.Read moreShow less
EWG 1 Perfuming
TOCOPHEROL
Antioxidant, Fragrance
Limited public safety data.Read moreShow less
EWG N/A AntioxidantFragranceSkin conditioning
Sodium Diethylenetriamine Pentamethylene Phosphonate
Chelating
Limited public safety data.Read moreShow less
EWG N/A Chelating
Sodium Gluceptate
Chelating
Limited public safety data.Read moreShow less
EWG N/A Chelating
Bisabolol
Fragrance, Skin conditioning
Limited public safety data.Read moreShow less
EWG N/A FragranceSkin conditioningSoothing
+ 1 more — see the full ingredients list above
Tocopheryl Acetate
Antioxidant, Skin conditioning
Potentially comedogenic - can block poresRead moreShow less
EWG 3 AntioxidantSkin conditioning Bad for Oily Skin
Retinol
Skin conditioning
Potentially a skin irritantRead moreShow less
EWG 9 CIR A Skin conditioning Bad for Sensitive Skin
Phenoxyethanol
Fragrance, Preservative
Low-to-moderate hazard.Read moreShow less
EWG 4 CIR A FragrancePreservative Paraben

How to use

How to use

  • 1 Evening: Use at night — start 2–3× a week and build up as your skin tolerates it.
  • 2 Wear SPF the next day: Acids and retinoids increase sun sensitivity — daily sunscreen is a must while using this.

General guidance from this product's category and active ingredients — always follow the directions on the package.

Trust & honesty

Pregnancy & breastfeeding

Contains ingredients some choose to avoid or double-check while pregnant or nursing.

Often avoided
Retinoids (Vitamin A) (Retinol)

Topical retinoids (retinol, retinaldehyde, retinyl esters) are widely advised against in pregnancy as a precaution. The strongest evidence is for ORAL retinoids; topical absorption is low, but most clinicians err on the side of caution.

This is general information, not medical advice. Pregnancy guidance varies and depends on concentration and your individual situation — always check with your doctor, midwife or pharmacist. How we flag this.

Effective levels — general guide

The concentrations these actives are typically effective at in research — not a measurement of this product.

Retinoids (Vitamin A) 0.01–1%

Most studied between 0.1% and 1%. Higher is not automatically better — irritation climbs with dose, so a well-formulated lower strength is often the sweet spot.

Retinol

INCI lists don't disclose amounts, and we don't claim to know this product's levels — these are the ranges these ingredients are usually effective at, so you can tell a real formula from "fairy-dusting" a marketed active. How we estimate this.

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