The library

Ingredient library

Every ingredient SkinAtlas knows about — all 2371 of them. What each one does, what it works well with, and what to watch for.

All 2371 ingredients — page 78 of 99

Other
Red 4
CI 14700

A synthetic red azo dye (CI 14700 / FD&C Red No. 4) approved as a cosmetic colorant in the US (external use only) and EU for use in cosmetics and personal care products.

colorant
Provides red coloration to cosmetic formulas
Azo dye class has theoretical mutagenicity concerns at high doses — regulatory assessments consider it safe at cosmetic concentrationsFDA approved for external use only (not lips or eye area) at ≤6%; EU Annex IV permitted colorant
Other
Red 6
CI 15850

D&C Red No. 6 (CI 15850), a synthetic organic monoazo dye providing red coloration. Used primarily in lip and nail products. Approved by the FDA for cosmetic use except around the eyes.

colorant
Synthetic monoazo dye used to impart red/pink shades in lip products and makeup
Synthetic azo dye; potential for contact sensitization in sensitive individualsNot approved for use around the eyes (FDA)
Antioxidant
Red Panax Ginseng Root Extract

An extract from Panax ginseng root that has been steamed and dried (red ginseng processing), which converts ginsenosides to heat-transformed forms (Rg2, Rh1) with enhanced antioxidant and skin-revitalizing potency compared to unprocessed white ginseng.

antioxidantbrighteningrevitalizing
Elevated Rg2 and Rh1 ginsenosides from heat processing enhance efficacyStronger antioxidant and revitalizing activity than unprocessed ginsengBrightening and anti-aging in luxury Korean skincare
Antioxidant
Rehmannia Chinensis Root Extract
REHMANNIA CHINENSIS ROOT EXTRACT

An extract from the root of Rehmannia chinensis (Chinese foxglove), one of the 50 fundamental herbs in TCM. Contains iridoid glycosides, oligosaccharides, and amino acids used for skin conditioning and antioxidant support in Japanese prestige skincare.

antioxidantskin-conditioninganti-inflammatory
Rich in iridoid glycosides (catalpol) with antioxidant activityTraditional Chinese Medicine ingredient for skin nourishmentMild anti-inflammatory
+ Niacinamide+ Artemisia Princeps Leaf Extract
Soothing
Rehmannia Glutinosa Root Extract

A rehmannia root extract that soothes, hydrates and offers antioxidant support to skin.

soothingantioxidanthumectant
Soothes and calms skinAntioxidant supportHelps hydrate and condition
+ Centella Asiatica+ Hyaluronic Acid
Antioxidant
Resveratrol

A polyphenol antioxidant from grapes.

ANTIOXIDANTSKIN PROTECTING
Antioxidant protectionSupports a brighter look
Active
Retinal
Retinaldehyde

A more potent retinoid one step closer to retinoic acid than retinol.

retinoid
Faster results than retinolSmooths textureAntibacterial
IrritationSun sensitivity
+ Niacinamide+ Ceramide NP
× Glycolic Acid× Lactic Acid
Active
Retinol

A vitamin A derivative that accelerates cell turnover.

retinoid
Smooths fine linesImproves textureHelps with acne
Irritation and peelingSun sensitivity
+ Niacinamide+ Ceramide NP+ Squalane
× Glycolic Acid× Lactic Acid
Active
Retinyl Acetate

An ester of retinol (vitamin A) and acetic acid — the mildest retinoid ester, requiring two enzymatic conversion steps to reach retinoic acid, giving it a gentler profile than retinol.

retinoidanti-aging
Gentlest retinoid ester — supports cell turnover with low irritationSmooths the look of fine linesSupports skin renewal
Increases photosensitivity — use SPF during the dayAvoid during pregnancy (all retinoids carry teratogenicity concern at high systemic doses)
Active
Retinyl Palmitate

The mildest common vitamin A ester. It converts slowly to retinol/retinoic acid in skin, giving low-irritation anti-aging benefits — weaker but gentler than retinol.

anti-aging
Smooths fine linesSupports cell turnoverGentle retinoid
Can increase sun sensitivity — pair with daytime SPFMay cause mild irritation in sensitive skin; introduce gradually
+ Niacinamide+ Tocopherol+ Hyaluronic Acid
× Ascorbic Acid× Glycolic Acid
Active
Retinyl Propionate

An ester of retinol (vitamin A) and propionic acid — a retinoid ester that converts to retinol and ultimately retinoic acid in the skin, delivering anti-aging activity with a gentler tolerability profile than retinol.

retinoidanti-aging
Supports cell turnover and skin renewal as a vitamin A esterReduces the appearance of fine lines and wrinklesGentler than retinol due to slower conversion to retinoic acid
Increases photosensitivity — use SPF during the dayAvoid during pregnancy (all retinoids carry teratogenicity concern at high systemic doses)
Active
Rhamnose

A naturally occurring deoxy sugar derived from plants (e.g. buckthorn, birch) with clinically demonstrated anti-aging activity: it stimulates collagen/elastin production and inhibits enzymes that degrade the extracellular matrix.

anti-aginghumectantprebiotic
Clinically shown to stimulate collagen I and elastin productionInhibits elastase, hyaluronidase, and collagenaseHelps reduce advanced glycation end-products (AGEs)
Active
Rheum Palmatum Root/Stalk Extract

An extract from the root and stalk of Rheum palmatum (Chinese rhubarb) containing anthraquinones (emodin, aloe-emodin, chrysophanol) and tannins with brightening, antioxidant, and anti-inflammatory properties.

brighteningantioxidantanti-inflammatory
Contains emodin and anthraquinones with brightening and antioxidant effectsAnti-inflammatory properties soothe skinMay help regulate sebum and address hyperpigmentation
Anthraquinones can be photosensitizing — caution in daytime use without adequate SPF
Fragrance
Rhodinols

A commercial fragrance mixture of rose alcohols (primarily citronellol and geraniol, with minor nerol and 3,7-dimethyloct-7-en-1-ol), used in cosmetics and perfumery for a characteristic rosy floral scent.

fragrant
Contributes a rich, rosy floral fragrance note
Mixture containing citronellol and geraniol — both are EU-regulated fragrance allergens requiring label disclosure above 0.001% (leave-on) and 0.01% (rinse-off)Sensitization risk for fragrance-allergic individuals
Antioxidant
Rhodiola Rosea Root Extract

An extract from the root of Rhodiola rosea (arctic rose), an adaptogenic plant whose key compounds rosavins and salidroside provide antioxidant, anti-inflammatory, and skin-protective benefits.

antioxidantadaptogenskin-conditioninganti-inflammatory
Rich in rosavins and salidroside for antioxidant protectionHelps protect skin against environmental and oxidative stressAnti-inflammatory and soothing properties
Antioxidant
Rhodomyrtus Tomentosa Fruit Extract
RHODOMYRTUS TOMENTOSA FRUIT EXTRACT

An extract from the berries of Rhodomyrtus tomentosa (downy rose myrtle), a tropical plant rich in myricetin, quercetin, and other polyphenolic antioxidants. Used in serums for antioxidant protection.

antioxidantsoothingskin-conditioning
Rich in polyphenols with strong antioxidant activityAnti-inflammatory and skin-soothingUsed in serums for brightening and protection
+ Tocopherol+ Ascorbyl Tetraisopalmitate
Antioxidant
Rhus Semialata Gall Extract

An extract from the galls formed on Rhus semialata (Chinese sumac) by aphid infestation, exceptionally rich in tannins and gallic acid, used for its astringent, antioxidant, and antimicrobial properties.

antioxidantastringentantimicrobialskin-conditioning
Very high tannin content provides potent astringent and pore-refining effectRich in gallic acid for strong antioxidant protectionAntimicrobial activity helps manage acne-causing bacteria
High tannin content may be drying or irritating at high concentrations
Antioxidant
Ribes Nigrum (Black Currant) Leaf Extract

Ribes Nigrum (Black Currant) Leaf Extract is derived from the leaves of the black currant shrub. Distinct from the more commonly used black currant seed oil and berry extract, the leaf extract is particularly rich in quercetin, myricetin, rutin, and caffeic acid derivatives with potent antioxidant and anti-inflammatory activity. Used in Korean vitamin C ampoules and antioxidant serums as a polyphenol-rich botanical active.

antioxidantanti-inflammatoryskin-conditioning
Black currant leaf extract is rich in quercetin, myricetin, and rutin flavonoids alongside caffeic and chlorogenic acids — all with documented antioxidant and anti-inflammatory activityLeaf extract's polyphenol profile provides stronger antioxidant capacity per gram than the berry (which prioritizes anthocyanins); the leaf fraction is especially rich in flavonol glycosidesDistinct from Ribes Nigrum Seed Oil (a GLA-rich lipid for barrier repair) — the leaf extract functions as an aqueous-phase antioxidant in serums and ampoules
+ Ascorbic Acid+ Tocopherol+ Niacinamide
Emollient
Ribes Nigrum (Black Currant) Seed Oil
Ribes Nigrum Seed Oil

A cold-pressed oil from Ribes nigrum (blackcurrant) seeds, exceptionally rich in gamma-linolenic acid (GLA) and omega-3 fatty acids that nourish the skin barrier and support a healthy lipid profile.

emollientbarrier-supportskin-conditioning
Rich source of gamma-linolenic acid (GLA) and alpha-linolenic acid (ALA) to support skin barrierNourishes and softens dry skinAnti-inflammatory fatty acid profile helps calm reactive skin
Antioxidant
Ribes Nigrum Fruit Extract
RIBES NIGRUM FRUIT EXTRACT

Extract from the fruit of Ribes nigrum (blackcurrant). Rich in anthocyanins, vitamin C, and flavonoids with potent antioxidant activity.

antioxidantsoothing
High anthocyanin antioxidant contentVitamin C and E support
+ Tocopherol+ Ascorbic Acid
Active
Riboflavin

Vitamin B2, a yellow flavin compound and essential coenzyme for cellular energy metabolism and antioxidant defense; used in cosmetics as a skin-conditioning agent and pigment (imparts yellow color at higher concentrations).

Skin conditioningVitaminAntioxidant
Antioxidant protection via flavin coenzyme activitySupports cellular energy metabolism in skinConditions skin
Other
Ribose

D-Ribose is a naturally occurring monosaccharide and the sugar backbone of RNA and ATP. In cosmetics it is used as a skin-conditioning humectant in powder and aqueous formulations. Claims that topical ribose supports cellular energy (by providing a substrate for ATP resynthesis) are biologically plausible but not strongly verified clinically at cosmetic concentrations. Used alongside ascorbic acid and other actives in vitamin C powder treatment formats.

skin-conditioninghumectant
D-Ribose is a pentose monosaccharide and essential precursor to ATP (adenosine triphosphate) and other nucleotides — claims exist that topical application can support cellular energy metabolism in skin cellsHygroscopic sugar that contributes mild humectant activity in aqueous formulationsUsed in premium powder treatments (notably Neogen's Dermalogy Real Vita C line) as a skin conditioning component alongside ascorbic acid
+ Ascorbic Acid+ Betaine+ Panthenol
Antioxidant
Rice Bran Extract
ORYZA SATIVA (RICE) BRAN EXTRACT

Extract from rice bran (the outer layer of the rice grain). Rich in ferulic acid, oryzanol (a mixture of phytosterol ferulates), tocotrienols, and ceramide precursors. A core Japanese beauty ingredient with antioxidant and mild brightening properties.

antioxidantskin-brighteningskin-conditioning
Rich in ferulic acid, oryzanol, and tocotrienolsAntioxidant and mild brighteningTraditional Japanese beauty ingredient
+ Tocopherol+ Niacinamide
Active
Rice Bran Fermentation Liquid
ORYZA SATIVA (RICE) BRAN FERMENT FILTRATE

A fermented filtrate from rice bran. Fermentation by microorganisms enhances the bioavailability of ferulic acid, oryzanol, and ceramide precursors in rice bran. Used in Bijin Nuka's fermented rice skincare line.

antioxidantskin-conditioningbarrier-support
Fermentation enhances bioavailability of rice bran activesCeramide precursors and sphingolipidsBarrier-supporting
+ Rice Bran Sphingoglycolipid+ Hydrogenated Lecithin