goop 20% Vitamin C Advanced Brightening Serum — 1 fl oz, L‑Ascorbic Acid + Hyaluronic Acid for Radiance & Hydration

goop Beauty 20% Vitamin C + Advanced Brightening Serum is a two-part, high-strength L‑ascorbic acid brightening serum formulated to even skin tone, boost radiance, and hydrate without tackiness.

This serum pairs a powdered 20% L‑ascorbic acid concentrate with a lightweight liquid activator so you get a fresh, potent antioxidant treatment at each use. The formula also includes ferulic acid for antioxidant support, hyaluronic acid for hydration, and ectoin to help soothe and support the skin barrier. The amber glass bottle and on-demand activation help protect stability and deliver an efficacious dose of vitamin C to address dullness and uneven texture.

How do I activate and apply this vitamin C serum?

Activation is quick: pour the liquid activator into the bottle of L‑ascorbic acid powder, cap, and shake until combined. Use a few drops on cleansed face and neck morning and night, layering under moisturizer and sunscreen during daytime.

• Empty activator into amber bottle containing powder and shake to dissolve.
• Apply 3–4 drops to face and neck after cleansing and before cream.
• Use mornings and/or evenings; always follow with broad-spectrum SPF in daytime.

What results can I expect and when might I see them?

Visible brightening and improved radiance are often reported within weeks of consistent use, as antioxidants help address surface discoloration and dullness while hydration smooths the skin’s appearance. Individual results vary by skin type and routine frequency.

• Formulated to target dullness and uneven tone with 20% L‑ascorbic acid.
• Includes ferulic acid to support antioxidant performance.
• Hyaluronic acid helps plump and reduce the look of fine texture.

Is this serum suitable for sensitive or reactive skin?

The formula contains a high concentration of pure vitamin C, which can be more active than lower-strength preparations. Ectoin and hyaluronic acid are included to soothe and hydrate, but a patch test is recommended if you have known sensitivity to vitamin C or active acids.

• Ectoin helps calm and protect against oxidative stress and water loss.
• Start with every-other-day application if you’re new to strong vitamin C serums.
• Stop use and consult a professional if prolonged irritation occurs.

How does the packaging help maintain potency?

The serum is supplied in two parts: a powder L‑ascorbic acid and a liquid activator that are combined immediately before use. This on-demand activation and the amber glass bottle reduce exposure to air and light, helping preserve the vitamin C’s effectiveness until you’re ready to use it.

• Two-part system keeps the active ingredient stable before mixing.
• Amber glass minimizes UV exposure to the activated serum.
• One-fluid-ounce size is convenient for daily use and travel-friendly.

Who is this for: This serum is designed for people seeking a potent topical vitamin C treatment to brighten and even skin tone while adding hydration. It’s appropriate for those comfortable introducing concentrated actives into their routine—especially users targeting dullness, discoloration, or texture concerns—who will follow with sunscreen during the day and patch-test if they have very reactive skin.

Ingredients

AQUA/WATER/EAU, ASCORBIC ACID, GLYCERIN, DIMETHYL ISOSORBIDE, PENTYLENE GLYCOL, ECTOIN, PROPANEDIOL, FERULIC ACID, SODIUM HYALURONATE, TERMINALIA FERDINANDIANA (KAKADU PLUM) FRUIT EXTRACT, GALACTOARABINAN, SODIUM CITRATE, ZIZIPHUS JUJUBA (JUJUBE) SEED EXTRACT, FRUCTAN, ETHYLHEXYLGLYCERIN, POTASSIUM SORBATE, DECYL GLUCOSIDE, OLEA EUROPAEA (OLIVE) LEAF EXTRACT, SODIUM HYDROXIDE, CITRIC ACID, PHENETHYL ALCOHOL, XYLITOL, CAPRYLIC ACID, CAPRYLYL GLYCOL.