goop Vitamin C Serum 20% L‑Ascorbic Acid Brightening Serum — Amber Activator Kit, Hyaluronic Acid & Ferulic

A potent daily brightening serum containing 20% L‑ascorbic acid, ferulic acid, hyaluronic acid, and ectoin formulated to even skin tone, hydrate, and boost radiance.

This two‑part serum arrives with a powder‑in‑bottle system to preserve potency: activate by emptying the included serum activator into the amber glass bottle with L‑ascorbic acid powder, shake, and apply. The formula combines a high concentration of pure vitamin C with ferulic acid and hydrating ingredients to target dullness and help improve the look of texture and tone while feeling lightweight and non‑tacky on skin.

How do I activate and apply this serum?

Activation is simple: pour the activator into the amber bottle containing the vitamin C powder, close, and shake until fully dissolved. Use a few drops on clean, dry skin morning and night, smoothing over face and neck before moisturizer and sunscreen in the daytime.

• Empty vial contents into amber bottle and securely close.
• Shake until powder fully dissolves and the solution looks uniform.
• Apply 2–4 drops to face and neck; follow with moisturizer and sunscreen.

What skin benefits can I expect and how soon?

The blend of 20% L‑ascorbic acid and ferulic acid delivers a concentrated antioxidant boost intended to address dullness and uneven tone. Clinical measurements showed improved radiance after four weeks of twice‑daily use in the tested panel; results can vary by individual skin type and routine consistency.

• Targets visible dullness and uneven complexion.
• Supports smoother-looking surface texture with ongoing use.
• Helps preserve hydration with hyaluronic acid and ectoin.

Why is the product packaged with an amber bottle and a separate activator?

Pure L‑ascorbic acid is sensitive to light and air, so keeping the powder separate until first use preserves freshness and potency. The amber glass helps minimize UV exposure after activation, extending stability for daily application.

• Powder form prevents early oxidation before activation.
• Amber glass reduces light exposure after mixing.
• Two‑part system ensures a fresher, more effective serum at first use.

Is this formula suitable for sensitive or dry skin?

The serum includes ectoin, an extremolyte known for skin‑soothing properties that can help support the skin barrier and reduce transepidermal water loss, plus hyaluronic acid for hydration. Because the vitamin C concentration is high, patch testing is recommended and those with very reactive skin may want to introduce use gradually.

• Ectoin calms and supports barrier function.
• Hyaluronic acid provides lightweight hydration without tackiness.
• Patch test on inner forearm before full face use; start every other day if needed.

Who is this for: This serum is designed for people seeking a high‑strength vitamin C treatment to target dullness, discoloration, and texture concerns while keeping a lightweight feel. It suits those comfortable with a two‑part activation system who want a fresher, potent L‑ascorbic acid formula and riders looking for hydrating, barrier‑supportive ingredients like hyaluronic acid and ectoin. If you have very sensitive skin, introduce the product slowly and consult a skincare professional if unsure.

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.