K-Beauty hydration serum designed for generous daily use. Absorbs in seconds, no stickiness, leaves skin visibly plump and glass-smooth. 150mL XXL size.

From MEDITHERAPY, a South Korean skincare brand known for clinically-inspired formulations at accessible price points. The 333 Hyaluronic Acid Serum is a first-step serum built around three core principles: 3-second absorption, 3-layer freshness, and 3D Hyaluronic hydration via the brand's proprietary Hyal-Block technology. Formulated with multiple molecular weights of Hyaluronic Acid alongside Ectoin, Centella Asiatica derivatives, and Glycerin for all-day visible moisture retention. Watery, lightweight, non-sticky texture that absorbs immediately and layers well under moisturizer or makeup. Generous 150mL XXL size designed for liberal daily application on face, neck, and body. Fragrance-free, paraben-free, silicone-free, alcohol-free. Suitable for all skin types.

Benefits:

• Hyal-Block Technology: A proprietary clustered Hyaluronic Acid structure designed to attract and lock visible moisture into the skin, helping maintain a plump, smooth appearance throughout the day.
  

• Multi-molecular Hyaluronic Acid complex: Sodium Hyaluronate, Hyaluronic Acid, Hydrolyzed Hyaluronic Acid, and Sodium Hyaluronate Crosspolymer target visible hydration at multiple surface depths simultaneously.
  

• Ectoin: A natural extremolyte derived from microorganisms found in extreme environments. Helps protect the visible appearance of the skin from environmental stressors and supports long-term visible moisture retention.
  

• Centella Asiatica derivatives (Asiaticoside, Asiatic Acid, Madecassic Acid): Visible soothing and barrier-supporting botanicals that work alongside the hydration actives.
  

• 3-second absorption. Watery, lightweight texture with no sticky residue. Layers seamlessly under moisturizer or makeup. Suitable as a primer hydration step for any skin type including oily and acne-prone.
  

• 150mL XXL size. Fragrance-free, paraben-free, silicone-free, alcohol-free. Suitable for face, neck, ears, hairline, and body.
  

What the 333 System Means

The 333 in the product name refers to the three-part hydration system MEDITHERAPY built this formula around. First, 3-second absorption: the watery texture is absorbed almost immediately on contact with the skin, with no wait time or heavy feeling. Second, 3-layer freshness: the formula delivers a fresh, lightweight feel at application while the hydration actives continue to work through the skin's surface layers. Third, 3D Hyaluronic hydration: multiple molecular weight forms of Hyaluronic Acid address different depths of the skin's surface simultaneously rather than just hydrating the outermost layer.

Why Ectoin

Ectoin is a natural amino acid derivative produced by microorganisms that survive in extreme environmental conditions such as salt flats and hot springs. It functions as a natural stress protectant in cosmetics, helping to stabilize the skin's visible moisture barrier against environmental aggressors including UV exposure, pollution, and temperature extremes. In hydrating serums, Ectoin enhances the visible water-binding capacity of the formula and helps the skin appear more resilient over time with consistent use.

Why 150mL

Most Hyaluronic Acid serums come in 30mL bottles at the same or higher price point. The 150mL XXL size is designed for generous, liberal application as a first step in any routine. Using a serum sparingly limits its visible effect. Applied generously to the face, neck, ears, and hairline after cleansing, the formula delivers a full layer of hydration that visibly plumps the skin before any subsequent steps. At 150mL, one bottle provides months of daily use rather than weeks.

How It Fits Into a Routine

This is a first-step serum, applied immediately after cleansing while the skin is still slightly damp. Damp skin allows Hyaluronic Acid to draw moisture from the skin's surface rather than the environment, maximizing the visible hydrating effect. Follow with the MEDITHERAPY Squalane Moisturizer to lock in the hydration. If using the MEDITHERAPY Retinal Serum, the recommended layering order is: this HA serum first, then the Retinal Serum, then the Squalane Moisturizer.

Ingredients

Water, Propanediol, Butylene Glycol, Glycerin, Tripropylene Glycol, Diethoxyethyl Succinate, 1,2-Hexanediol, Ectoin, Hydroxyacetophenone, Glycereth-25 PCA Isostearate, Sodium Hyaluronate, Poloxamer 407, Arginine, Carbomer, Ethylhexylglycerin, Disodium EDTA, Xanthan Gum, Asiaticoside, Asiatic Acid, Madecassic Acid, Hyaluronic Acid, Hydrolyzed Hyaluronic Acid, Sodium Hyaluronate Crosspolymer.

Directions

Apply generously to cleansed skin as the first serum step, preferably while skin is still slightly damp after cleansing. Smooth over face, neck, ears, and hairline. Gently pat to aid absorption. Follow with moisturizer. Suitable for morning and evening use. For external use only. Avoid contact with eyes.