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Shop TIRTIR Pure Vitamin C 24% Face Serum
Serum
TIRTIR

Pure Vitamin C 24% Face Serum

~$23.97· 30ml / 1.01 fl ozPM only
Dark spotsRadianceFine lines & firmnessDryness

What it's good for

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

  • Vitamin CStrong evidenceFull dossier ↗

    Brightens dull skin and helps fade dark spots. Also defends against everyday UV and pollution damage when worn under sunscreen.

    Good for: Brightening, Antioxidant

  • Centella AsiaticaModerate evidenceFull dossier ↗

    Also called "cica," it calms redness, repairs the skin barrier, and speeds up recovery. The go-to for irritated or reactive skin.

    Good for: Anti-inflammatory, Barrier repair

  • Hydrolyzed CollagenModerate evidenceFull dossier ↗

    The protein your skin loses with age, broken down small enough to absorb. Multiple meta-analyses of RCTs show measurable wins in wrinkles, elasticity, and hydration after ~12 weeks. Most evidence is oral, but topical helps surface hydration too.

    Good for: Anti-aging, Hydrating

  • Matrixyl PeptidesModerate evidenceFull dossier ↗

    Signals your skin to make more collagen. Quiet but real support for firmness and fine lines with consistent daily use.

    Good for: Anti-aging

  • GlycerinModerate evidenceFull dossier ↗

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

    Good for: Hydrating

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.

Vitamin CStrong evidence15 citations

Brightens dull skin and helps fade dark spots. Also defends against everyday UV and pollution damage when worn under sunscreen.

Krutmann J et al. PINGing Sunshine: A Review of the Evidence for Adding Non-Filtering Photoprotective Ingredients to Sunscreens. Photodermatol Photoimmunol Photomed. 2025;41(6). — Review of Photoprotective INGredients (PINGs); L-ascorbic acid (vitamin C) identified as a top-ranked PING demonstrating efficacy across multiple photodamage endpoints.

2025Meta-analysis (positive)PMID:41152208View source ↗

Pullar JM et al., The roles of vitamin C in skin health, Nutrients 2017;9(8):866 — concluded topical efficacy "poorly understood"; supports dietary vitamin C

2017Mechanism onlyPMID:28805671View source ↗

Lee JH et al., Effects of VitabridC12 on Skin Inflammation, Annals of Dermatology 2017

2017Mechanism onlyPMID:28966510View source ↗
Centella AsiaticaModerate evidence6 citations

Also called "cica," it calms redness, repairs the skin barrier, and speeds up recovery. The go-to for irritated or reactive skin.

Hur N et al., A Randomized, Double-Blind, Placebo-Controlled Trial Assessing the Effects of Oral Centella asiatica Extract on Skin Aging-Related Parameters in Middle-Aged Korean Women, Nutrients 2026

2026Positive (efficacy)PMID:42196964View source ↗

Borowicz KK et al., Geroprotective Potential of Centella asiatica: Modulation of Cellular Aging, Nutrients 2026

2026Mechanism onlyPMID:42280293View source ↗

Witkowska K et al., Topical Application of Centella asiatica in Wound Healing: Recent Insights into Mechanisms and Clinical Efficacy, Pharmaceutics 2024;16(10):1252 — modern hydrogel and nanostructured Centella delivery systems accelerate wound healing across wound types

2024Meta-analysis (positive)PMID:39458583View source ↗
Hydrolyzed CollagenModerate evidence7 citations

The protein your skin loses with age, broken down small enough to absorb. Multiple meta-analyses of RCTs show measurable wins in wrinkles, elasticity, and hydration after ~12 weeks. Most evidence is oral, but topical helps surface hydration too.

Reilly DM, Kynaston L, Naseem S, Proudman E, Laceby D. A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen. Dermatology Research and Practice. 2024. — Randomized double-blind placebo-controlled trial; 12-week oral collagen supplement showed 44.6% decrease in collagen fragmentation, +13.8% hydration, +22.7% elasticity, -19.6% wrinkle index vs placebo.

2024Positive (efficacy)PMID:39021368View source ↗

Demir-Dora D, Ozsoy U, Yildirim Y, et al. The Efficacy and Safety of CollaSel Pro® Hydrolyzed Collagen Peptide Supplementation without Addons in Improving Skin Health in Adult Females: A Double Blind, Randomized, Placebo-Controlled Clinical Study. Journal of Clinical Medicine. 2024 Sep 11. — Double-blind RCT (n=112); significant improvements in skin elasticity (p=0.009), hydration (p<0.001), and roughness vs placebo.

2024Positive (efficacy)PMID:39336856View source ↗

Pu SY et al., Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis, Nutrients 2023;15(9):2080 — 26 RCTs / 1,721 patients: hydrolyzed collagen significantly improved skin hydration and elasticity vs placebo across multiple collagen sources

2023Meta-analysis (positive)PMID:37432180View source ↗
+2 more ingredients
Matrixyl PeptidesModerate evidence6 citations

Signals your skin to make more collagen. Quiet but real support for firmness and fine lines with consistent daily use.

Yang Y et al., Comprehensive evaluation of the efficacy and safety of a new multi-component anti-aging topical eye cream, Skin Research and Technology 2024;30(7):e13790 — 12-week study of active complex containing Matrixyl 3000 peptides showed significant improvement in hydration, elasticity, periorbital wrinkles

2024Positive (efficacy)PMID:38932444View source ↗

Aruan RR et al., Double-blind, Randomized Trial on the Effectiveness of Acetylhexapeptide-3 Cream and Palmitoyl Pentapeptide-4 Cream for Crow's Feet, Journal of Clinical and Aesthetic Dermatology 2023;16(2):37-43 — RCT of topical palmitoyl pentapeptide-4 (Matrixyl) for periorbital wrinkles

2023Positive (efficacy)PMID:36909866View source ↗

Imhof L, Leuthard D, Topical Over-the-Counter Antiaging Agents: An Update and Systematic Review, Dermatology 2021;237(2):217-229 — SR covering topical antiaging peptides

2021Meta-analysis (positive)PMID:32882685View source ↗
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 ↗

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.

  • Benzoyl peroxide breaks down vitamin C, making both less effective. Use one in the morning and the other at night.

  • Vitamin C and retinol work best at different pH levels. Use vitamin C in the morning and retinol at night.

Similar comparisons

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Not medical advice. GlowPal is educational. Patch-test new products and talk to a qualified healthcare professional before changing your routine, especially if you're pregnant, nursing, or have a diagnosed skin condition. See our terms.