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Research connections

Skin research: compare the whole formulation and the measured outcome

The skincare catalog combines recurring ingredients in different concentrations. A formulation map makes those overlaps visible, then connects each ingredient to the experiment or clinical study that measured it.

The same ingredient can belong to different questions

Tretinoin appears as a separate cream and in products containing niacinamide, vitamin C, hydroquinone, dapsone or azelaic acid. A photoaging paper and an acne paper can both concern tretinoin while measuring different outcomes. The 1988 vehicle-controlled study displayed in the atlas addressed photoaging over sixteen weeks.

Niacinamide appears at several catalog concentrations. The 2005 split-face study used 5% niacinamide over twelve weeks and measured several appearance-related outcomes. Matching the ingredient percentage is useful, but the study vehicle and the product’s companion ingredients still need to be retained.

Sources: PMID 3336176 · PMID 16029679

Connect laboratory findings without changing their meaning

The hydroquinone-kojic-acid-niacinamide product is connected to a paper examining skin-lightening ingredients in cells. That experiment can help explain an ingredient’s laboratory history. It does not report a visible result from people using this catalog cream.

The copper-tripeptide study examined penetration and retention in isolated human skin layers. Human tissue in an experiment is different from a clinical trial in living participants. A tissue-penetration result and a measured cosmetic outcome should remain separate endpoints.

Sources: PMID 23738040 · PMID 20703511

A concentration match is only one part of a formulation match

The estriol blend contains estriol 0.3%, vitamin C 5% and hydrolyzed hyaluronic acid 0.5%. A historical study examined 0.3% estriol and 0.01% estradiol preparations in fifty-nine women over six months. The matching estriol percentage provides a precise connection, while the other catalog ingredients keep the complete blend distinct.

The urea paper includes human observations, cell experiments and an animal model. Reading those sections separately helps connect its findings to a skin formulation without treating every experiment as the same kind of evidence.

Sources: PMID 8876303 · PMID 22418868

The formulation network

Each row connects a current product to the ingredient research behind its listed formulation.

Tretinoin Cream

Tretinoin 0.025 / 0.05 / 0.1%

Tretinoin

Tretinoin + Niacinamide Cream

Tretinoin + Niacinamide 4% + Hyaluronic Acid

TretinoinNiacinamideHyaluronic acid

Hydroquinone 8% Cream

Hydroquinone 8% / Tretinoin / Vitamin C / Niacinamide

HydroquinoneTretinoinVitamin CNiacinamide

Dapsone Acne Cream

Dapsone 3% / Tretinoin 0.07% / Niacinamide 4%

DapsoneTretinoinNiacinamide

Azelaic Acid Cream

Azelaic Acid 5% / Tretinoin 0.03% / Niacinamide 4%

Azelaic acidTretinoinNiacinamide

Tretinoin / Niacinamide / Vitamin C

tretinoin 0.05%, niacinamide 5% and vitamin C 5%

TretinoinNiacinamideVitamin C

Rosacea Cream (Oxymetazoline + Ivermectin)

Oxymetazoline 0.88% / Ivermectin 0.88% / Niacinamide 4%

OxymetazolineIvermectinNiacinamide

Hydroquinone / Kojic Acid / Niacinamide

hydroquinone 6%, kojic acid 6% and niacinamide 5%

HydroquinoneKojic acidNiacinamide

Salicylic Acid / Zinc Oxide / Niacinamide / Urea

salicylic acid 2%, zinc oxide 5%, niacinamide 8% and urea 2%

Salicylic acidZinc oxideNiacinamideUrea

Bimatoprost Lash Serum

Bimatoprost 0.03%

Bimatoprost

Estriol / Vitamin C / Hyaluronic Acid

estriol 0.3%, vitamin C 5% and hydrolyzed hyaluronic acid 0.5%

EstriolVitamin CHyaluronic acid

Copper Peptide Cream

Copper peptide 0.2%

Copper peptide / GHK-Cu

Read the source studies

Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled study.Weiss JS, Ellis CN, Headington JT, Tincoff T, Hamilton TA, Voorhees JJ. JAMA. 1988-01-01.
Niacinamide: A B vitamin that improves aging facial skin appearance.Bissett DL, Oblong JE, Berge CA. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2005-07-01.
Examining the impact of skin lighteners in vitro.Gruber JV, Holtz R. Oxidative medicine and cellular longevity. 2013-04-28.
Human skin retention and penetration of a copper tripeptide in vitro as function of skin layer towards anti-inflammatory therapy.Hostynek JJ, Dreher F, Maibach HI. Inflammation research : official journal of the European Histamine Research Society ... [et al.]. 2010-08-13.
Treatment of skin aging with topical estrogens.Schmidt JB, Binder M, Demschik G, Bieglmayer C, Reiner A. International journal of dermatology. 1996-09-01.
Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression.Grether-Beck S, Felsner I, Brenden H, Kohne Z, Majora M, Marini A, Jaenicke T, Rodriguez-Martin M, Trullas C, Hupe M, Elias PM, Krutmann J. The Journal of investigative dermatology. 2012-03-15.

Research synthesis by HealthRX.com, October 5, 2026. The cited sources and linked ingredient pages describe the scope of this comparison.