Vitamin C Serum
What it's good for
Key actives from our research database. Click any to read the full evidence 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
A pure hydrator that holds water in your skin. Makes skin look plumper and smoother almost immediately.
Good for: Hydrating
A plant-derived acid that blocks the enzyme your skin uses to make pigment, fading dark spots and post-acne marks. Clinical trials show it measurably reduces hyperpigmentation and improves skin luminosity, with significantly less irritation than stronger AHAs. A good option for sensitive skin that still wants a brightening acid.
Good for: Brightening, Antioxidant, Exfoliating
Brightens dull skin and helps fade dark spots. Also defends against everyday UV and pollution damage when worn under sunscreen.
Good for: Brightening, Antioxidant
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.
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.
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.
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.
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.
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
Lee SG et al., Hyaluronan Oligosaccharides Improve Rosacea-Like Phenotype through Anti-Inflammatory and Epidermal Barrier-Improving Effects, Annals of Dermatology 2020
A plant-derived acid that blocks the enzyme your skin uses to make pigment, fading dark spots and post-acne marks. Clinical trials show it measurably reduces hyperpigmentation and improves skin luminosity, with significantly less irritation than stronger AHAs. A good option for sensitive skin that still wants a brightening acid.
Markiewicz-Tomczyk A et al., Clinical Evaluation of Anti-Aging Effects of Combined Therapy - Azelaic Acid, Phytic Acid, and Vitamin C Applied Layer by Layer in Females, Journal of Cosmetic Dermatology 2022
Houshmand EB. Effect of glycolic acid, phytic acid, soothing complex containing emulsion on hyperpigmentation and skin luminosity: a clinical evaluation. J Cosmet Dermatol. 2021;20(3):776-780.
Sarkar R et al. Comparative Study of 35% Glycolic Acid, 20% Salicylic-10% Mandelic Acid, and Phytic Acid Combination Peels in the Treatment of Active Acne and Postacne Pigmentation. J Cutan Aesthet Surg. 2019;12(3):158-163.
+−1 more ingredient
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.
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
Lee JH et al., Effects of VitabridC12 on Skin Inflammation, Annals of Dermatology 2017
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 Peroxidemedium
Benzoyl peroxide breaks down vitamin C, making both less effective. Use one in the morning and the other at night.
- Retinollow
Vitamin C and retinol work best at different pH levels. Use vitamin C in the morning and retinol at night.
Similar comparisons
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.