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Serum
Auteur

Definitive Renewal Serum

~$558

What it's good for

Key actives from our research database. Click any to read the full evidence dossier.

  • ArgirelineModerate evidenceFull dossier ↗

    Sometimes called "topical Botox," it's a peptide that subtly reduces the depth of expression lines around the eyes and forehead when used daily over months. Mild effect, but real.

    Good for: Anti-aging

  • CeramidesStrong evidenceFull dossier ↗

    Refills the natural barrier between your skin cells. Locks moisture in, keeps irritants out, calms dry or damaged skin.

    Good for: Barrier repair

  • Citric AcidModerate evidenceFull dossier ↗

    A fruit-derived AHA that exfoliates and antioxidizes. It shares the same basic mechanism as glycolic and lactic acid but is weaker gram-for-gram; in practice you'll see it doing dual duty (a little exfoliation plus pH stabilisation) in multi-acid toners and serums. When it appears low on an ingredient list, it's adjusting pH; higher up, it's contributing real exfoliation.

    Good for: Exfoliating, Antioxidant

  • GlycerinModerate evidenceFull dossier ↗

    A workhorse hydrator that pulls water into your skin. In nearly every good moisturizer for a reason.

    Good for: Hydrating

  • Hyaluronic AcidStrong evidenceFull dossier ↗

    A pure hydrator that holds water in your skin. Makes skin look plumper and smoother almost immediately.

    Good for: Hydrating

  • Lactic AcidStrong evidenceFull dossier ↗

    A gentler exfoliator that also hydrates as it works. Good entry point if you have sensitive skin and want to try acids.

    Good for: Exfoliating, Hydrating

  • NiacinamideStrong evidenceFull dossier ↗

    A multitasker that calms redness, evens out skin tone, and helps oily skin balance out. One of the safest do-a-little-of-everything ingredients.

    Good for: Brightening, Barrier repair, Anti-inflammatory

  • Shea ButterModerate evidenceFull dossier ↗

    A rich, naturally occlusive plant butter from the African karite tree. Soothes dry, irritation-prone skin, refills the lipid barrier, and was well tolerated enough in randomized trials that most participants used it comfortably as a daily emollient.

    Good for: Barrier repair, Hydrating, Anti-inflammatory

  • Sodium PCAAnecdotal evidenceFull dossier ↗

    Replenishes one of the actual humectant molecules your own skin makes. Levels drop in eczema and with age, so topping it up genuinely helps dry, dehydrated, or atopic-prone skin feel less tight.

    Good for: Hydrating, Barrier repair

  • SqualaneAnecdotal evidenceFull dossier ↗

    A lightweight oil that mimics what your skin already makes. Softens and seals in hydration without feeling greasy.

    Good for: Barrier repair, Hydrating

  • Vitamin EModerate evidenceFull dossier ↗

    A workhorse antioxidant that defends your skin from daily oxidative damage. Pairs especially well with vitamin C, and it's in nearly every good moisturizer for a reason.

    Good for: Antioxidant

New to this? Patch test on your inner arm for 24 to 48 hours before applying to your face. If you have sensitive skin or rosacea, start 2 to 3 times per week and build up slowly.

Evidence behind the ingredients

Real citations from our research database, one per tracked active in this product. Click any ingredient name to read its full evidence dossier.

ArgirelineModerate evidence6 citations

Sometimes called "topical Botox," it's a peptide that subtly reduces the depth of expression lines around the eyes and forehead when used daily over months. Mild effect, but real.

Zhu M et al., The effect of a serum containing acetyl hexapeptide-8, dipeptide diaminobutyroyl benzylamide diacetate and gluconolactone on skin biomarkers, wrinkles and skin texture: ex vivo and clinical studies, International Journal of Cosmetic Science 2026 — two clinical trials (n=50, n=42) showed 35-69% static wrinkle improvement and significant elastic fiber and collagen biomarker increases at 12 weeks

2026Positive (efficacy)PMID:41668671View source ↗

Zdrada-Nowak J, Surgiel-Gemza A, Szatkowska M, Acetyl Hexapeptide-8 in Cosmeceuticals: A Review of Skin Permeability and Efficacy, International Journal of Molecular Sciences 2025

2025InconclusivePMID:40565185View source ↗

Henseler H, Investigating the effects of Argireline in a skin serum containing hyaluronic acids on skin surface wrinkles using the Visia Complexion Analysis camera system, GMS Interdisciplinary Plastic and Reconstructive Surgery DGPW 2023;12:Doc09 — topical argireline serum reduced measured surface wrinkles

2023Positive (efficacy)PMID:38024099View source ↗
CeramidesStrong evidence7 citations

Refills the natural barrier between your skin cells. Locks moisture in, keeps irritants out, calms dry or damaged skin.

Andrew PV et al., Topical supplementation with physiological lipids rebalances the stratum corneum ceramide profile and strengthens skin barrier function in adults predisposed to atopic dermatitis, British Journal of Dermatology 2025;193(4):729-740 — physiological-lipid emulsion raised SC ceramide NP/AP and improved barrier function vs control

2025Positive (efficacy)PMID:40408261View source ↗

Nugroho WT, Sawitri, Astindari, Utomo B, Listiawan MY, Ervianti E, Astari L. The Efficacy of Moisturisers Containing Ceramide Compared with Other Moisturisers in the Management of Atopic Dermatitis: A Systematic Literature Review and Meta-Analysis. Indian J Dermatol. 2023;68(1):53-58. — Meta-analysis of 5 studies found ceramide-containing moisturisers produced significantly greater improvement in SCORAD compared with non-ceramide moisturisers in atopic dermatitis.

2023Meta-analysis (positive)PMID:37151263View source ↗

Shindo S et al., Effects of a moisturizer containing pseudo-ceramide and a eucalyptus extract on sweating function in adult atopic dermatitis: a double-blind, randomized, controlled left-right comparison clinical trial, Journal of Cosmetic Dermatology 2022;21(10):4503-4509 — pseudo-ceramide + eucalyptus moisturizer restored sweating function and barrier in AD adults

2022Positive (efficacy)PMID:35298858View source ↗
Citric AcidModerate evidence4 citations

A fruit-derived AHA that exfoliates and antioxidizes. It shares the same basic mechanism as glycolic and lactic acid but is weaker gram-for-gram; in practice you'll see it doing dual duty (a little exfoliation plus pH stabilisation) in multi-acid toners and serums. When it appears low on an ingredient list, it's adjusting pH; higher up, it's contributing real exfoliation.

Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. 2018;23(4):863.

2018Mechanism onlyPMC:PMC6017965View source ↗

Yamamoto Y, Uede K, Yonei N, Kishioka A, Ohtani T, Furukawa F. Effects of alpha-hydroxy acids on the human skin of Japanese subjects: the rationale for chemical peeling. Journal of Dermatology. 2006 Jan;33(1):16-22. — Clinical-mechanistic study in Japanese subjects demonstrating AHA (including citric acid class) keratolytic and epidermal renewal effects as rationale for chemical peeling.

2006Mechanism onlyPMID:16469079View source ↗

Bernstein EF, Underhill CB, Lakkakorpi J, et al. Citric acid increases viable epidermal thickness and glycosaminoglycan content of sun-damaged skin. Dermatologic Surgery. 1997 Aug;23(8):689-694. — Mechanistic study showing topical citric acid increased viable epidermal thickness and dermal glycosaminoglycans in sun-damaged skin, similar to glycolic acid and retinoic acid.

1997Mechanism onlyPMID:9256916View source ↗
+8 more ingredients
GlycerinModerate evidence6 citations

A workhorse hydrator that pulls water into your skin. In nearly every good moisturizer for a reason.

Danby SG et al., Different types of emollient cream exhibit diverse physiological effects on the skin barrier in adults with atopic dermatitis, Clinical and Experimental Dermatology 2022;47(6):1154-1164 — glycerol+urea emollient delivered superior barrier-strengthening and irritant protection

2022Positive (efficacy)PMID:35167133View source ↗

Youssef R et al., Glycerol 85% efficacy on atopic skin and its microbiome: a randomized controlled trial, Journal of Dermatological Treatment 2021;32(7):730-736 — topical glycerol 85% RCT on atopic skin

2021Positive (efficacy)PMID:31869257View source ↗

Evans NJ et al., Human axillary skin condition is improved following incorporation of glycerol into the stratum corneum from an antiperspirant formulation, Archives of Dermatological Research 2017;309(9):739-748 — 4% glycerol penetrated axillary SC, reduced irritation, improved hydration

2017Positive (efficacy)PMID:28889318View source ↗
Hyaluronic AcidStrong evidence7 citations

A pure hydrator that holds water in your skin. Makes skin look plumper and smoother almost immediately.

Karabat MU, Tuncer MC. Effects of hyaluronic acid on skin at the cellular level: a systematic review. Rev Assoc Med Bras. 2025;71(8):e20250208. — Systematic review of 45 studies found low-molecular-weight HA stimulates keratinocyte proliferation and migration while high-molecular-weight HA drives skin hydration, supporting topical HA as an effective skin-hydrating and barrier-supporting ingredient.

2025Meta-analysis (positive)PMID:40990743View source ↗

Bravo B et al., Benefits of topical hyaluronic acid for skin quality and signs of skin aging: From literature review to clinical evidence, Dermatology and Therapy 2022;12(12):2657-2680 — HA-based cosmeceuticals reliably improve hydration and signs of skin aging

2022Meta-analysis (positive)PMID:36200921View source ↗

Lee SG et al., Hyaluronan Oligosaccharides Improve Rosacea-Like Phenotype through Anti-Inflammatory and Epidermal Barrier-Improving Effects, Annals of Dermatology 2020

2020Mechanism onlyPMID:33911737View source ↗
Lactic AcidStrong evidence5 citations

A gentler exfoliator that also hydrates as it works. Good entry point if you have sensitive skin and want to try acids.

Fanning N et al., Treatment of mild-to-moderate facial cutaneous aging using a combination peel containing 6% trichloroacetic acid and 12% lactic acid, Journal of Cosmetic Dermatology 2023;22(11):3033-3041 — three monthly peels significantly improved clarity, pigmentation, fine lines, roughness in 32 subjects

2023Positive (efficacy)PMID:37227430View source ↗

Tang SC, Yang JH, Dual effects of alpha-hydroxy acids on the skin, Molecules 2018;23(4):863 — effect concentration-dependent

2018Positive (efficacy)PMID:29642579View source ↗

Babilas P et al., Cosmetic and dermatologic use of alpha hydroxy acids, JDDG: Journal der Deutschen Dermatologischen Gesellschaft 2012 — supports AHAs including lactic acid for photoaging, pigmentation, and barrier effects

2012Meta-analysis (positive)PMID:22916351View source ↗
NiacinamideStrong evidence10 citations

A multitasker that calms redness, evens out skin tone, and helps oily skin balance out. One of the safest do-a-little-of-everything ingredients.

Moro F et al., Skin Cancer Prevention and Antiaging: Role of Nicotinamide, International Journal of Molecular Sciences 2026

2026Mechanism onlyPMID:42278444View source ↗

Passeron T et al., An Investigator-Blinded, Randomized Trial of a Broad-Spectrum Sunscreen Containing Sclareolide and Niacinamide, Dermatology and Therapy (Heidelberg) 2026

2026Positive (efficacy)PMID:41240206View source ↗

Vergilio MM et al., Topical Formulation with Niacinamide Combined with 5 MHz Ultrasound for Improving Skin Ageing, Current Medicinal Chemistry 2025

2025Positive (efficacy)PMID:39171587View source ↗
Shea ButterModerate evidence4 citations

A rich, naturally occlusive plant butter from the African karite tree. Soothes dry, irritation-prone skin, refills the lipid barrier, and was well tolerated enough in randomized trials that most participants used it comfortably as a daily emollient.

O'Connor RJ et al., Clinical Evaluation of a Diaper Containing a Shea Butter-Based Emollient and Impact on Diapered Skin Erythema, Pediatr Dermatol 2025;42(3):532-538 — RCT n=271 infants, shea-butter diaper reduced dermatitis

2025Positive (efficacy)PMID:40189822View source ↗

Burnett CL, Bergfeld WF, Belsito DV, et al. Safety Assessment of Butyrospermum parkii (Shea)-Derived Ingredients as Used in Cosmetics. Cosmetic Ingredient Review Expert Panel Final Report.

2024Safety assessmentDOI:10.1177/10915818231224230View source ↗

Verallo-Rowell VM, Katalbas SS, Pangasinan JP. Natural (Mineral, Vegetable, Coconut, Essential) Oils and Contact Dermatitis. Curr Allergy Asthma Rep. 2016;16(7):51. — discussing shea butter unsaponifiable fraction NF-kB inhibition and dermatologic use.

2016Mechanism onlyPMID:27373890View source ↗
Sodium PCAAnecdotal evidence4 citations

Replenishes one of the actual humectant molecules your own skin makes. Levels drop in eczema and with age, so topping it up genuinely helps dry, dehydrated, or atopic-prone skin feel less tight.

Novel design of pyrrolidonecarboxylic acid and sodium dilauramidoglutamide lysine complex for targeted drug delivery to human stratum corneum, International Journal of Pharmaceutics 2025

2025Mechanism onlyPMID:40187708View source ↗

Baldwin H, Del Rosso J, Going Beyond Ceramides in Moisturizers: The Role of Natural Moisturizing Factors, Journal of Drugs in Dermatology 2024 — review establishing PCA (pyrrolidone carboxylic acid) as a core skin natural moisturizing factor alongside amino acids, urea, lactate, and electrolytes; essential to barrier function and xerosis treatment

2024Mechanism onlyPMID:38834224View source ↗

Li L et al., Association Between Skin Acid Mantle, Natural Moisturizing Factors, and Antibacterial Activity Against S. aureus in the Stratum Corneum, Clinical Cosmetic and Investigational Dermatology 2023 — PCA and urocanic acid as NMF components contribute to skin antibacterial defense; 1-unit pH drop = 68.1% S. aureus cell death

2023Mechanism onlyPMID:37378303View source ↗
SqualaneAnecdotal evidence5 citations

A lightweight oil that mimics what your skin already makes. Softens and seals in hydration without feeling greasy.

Wolosik K et al., Squalane as a Promising Agent Protecting UV-Induced Inhibition of Collagen Biosynthesis and Wound Healing in Human Dermal Fibroblast, Molecules 2025;30(9):1964 — low-dose squalane (0.005-0.015%) restored collagen biosynthesis and wound healing in UVA-exposed human dermal fibroblasts

2025Mechanism onlyPMID:40363772View source ↗

Morgan AB et al., Explicating the multifunctional roles of tocotrienol and squalene in promoting skin health, Skin Health and Disease 2024;4(5):e448 — squalene/squalane promotes skin health via antioxidant, hydrating, emollient, anti-inflammatory mechanisms

2024Mechanism onlyPMID:39355739View source ↗

Fiume M et al., Safety Assessment of Squalane and Squalene as Used in Cosmetics, International Journal of Toxicology 2023;42(3_suppl):107S-109S — CIR expert-panel assessment concluding squalane is safe as a cosmetic ingredient

2023Safety assessmentPMID:37752766View source ↗
Vitamin EModerate evidence6 citations

A workhorse antioxidant that defends your skin from daily oxidative damage. Pairs especially well with vitamin C, and it's in nearly every good moisturizer for a reason.

Neves JR et al., Efficacy of a topical serum containing L-ascorbic acid, neohesperidin, pycnogenol, tocopherol, and hyaluronic acid in relation to skin aging signs, Journal of Cosmetic Dermatology 2022;21(10):4462-4469 — tocopherol-containing antioxidant serum reduced pollution-induced damage and improved aging signs

2022Positive (efficacy)PMID:35150043View source ↗

Warshaw EM et al., Patch Testing With Tocopherol and Tocopherol Acetate: The North American Contact Dermatitis Group Experience, 2001 to 2016, Dermatitis 2021;32(5):308-318 — 15-year NACDG data: positive patch-test reactions to tocopherol rare given widespread cosmetic use

2021Safety assessmentPMID:34238818View source ↗

Lin FH et al., Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin, Journal of Investigative Dermatology 2005;125(4):826-832 — ferulic acid + vit C + vit E combo doubled photoprotection vs C+E alone (cross-listed; same paper cited for Ferulic Acid and Vit C)

2005Positive (efficacy)PMID:16185284View source ↗

Sources: 10 clinical journals and regulatory databases across the US, EU, Korea, Japan, and China. Every entry points to a specific document. See methodology for the full list and what each outcome label means.

Layering conflicts

Ingredients in this product that can react with common actives. Avoid stacking unless noted.

  • Tretinoin + lactic acid — stack of two active resurfacers, very irritating.

  • Retinolmedium

    Retinol + lactic acid is gentler than glycolic but still alternate nights to be safe.

Similar comparisons

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