Hyaluronic acid is the most-searched skincare ingredient globally. But not all HA is created equal. This deep-dive covers molecular weights, concentration science, and how to formulate HA products that actually deliver results.
The Science Behind Hyaluronic Acid
Hyaluronic acid (HA) is a glycosaminoglycan — a naturally occurring polysaccharide found in the skin's extracellular matrix. A single gram of HA can hold up to 6 liters of water, making it one of the most powerful humectants in cosmetic science.
But the effectiveness of HA in a formula depends critically on molecular weight.
Molecular Weight: The Most Important Variable
High Molecular Weight HA (>1,000 kDa)
- Forms a film on the skin surface
- Provides immediate plumping and smoothing effect
- Does not penetrate the epidermis
- Best for: creams, lotions, sheet masks
Medium Molecular Weight HA (100–1,000 kDa)
- Penetrates the upper layers of the epidermis
- Provides sustained hydration
- Best for: serums, essences
Low Molecular Weight HA (<100 kDa)
- Penetrates deeper into the dermis
- Stimulates collagen synthesis
- Can cause mild inflammation at high concentrations
- Best for: targeted anti-aging serums, ampoules
Sodium Hyaluronate (Salt Form)
Most commercial HA is actually sodium hyaluronate — the sodium salt of HA. It is more stable, water-soluble, and penetrates more effectively than pure HA. At SEYE, we use pharmaceutical-grade sodium hyaluronate in all our HA formulas.
Optimal Concentration Ranges
| Product Type | Recommended HA Concentration |
|---|---|
| Hydrating Serum | 1.0–2.0% |
| Face Cream | 0.1–0.5% |
| Eye Cream | 0.1–0.3% |
| Sheet Mask Essence | 0.5–1.5% |
| Ampoule | 2.0–5.0% |
Formulation Note: Higher concentration does not always mean better performance. Above 2% in serums, HA can feel sticky and may reduce consumer satisfaction scores.
Multi-Weight HA: The Gold Standard
The most effective HA formulas use multiple molecular weights simultaneously — a strategy we call "layered hydration architecture":
- High MW HA creates a surface moisture barrier
- Medium MW HA hydrates the epidermis
- Low MW HA stimulates dermal collagen
SEYE's signature Tri-Weight HA Complex is used across our premium serum and ampoule lines, delivering clinically measurable improvements in skin hydration within 28 days.
Stability Considerations
HA is sensitive to:
- pH: Optimal stability at pH 5.0–7.0. Avoid formulating with AHAs without buffering.
- Temperature: Store below 25°C; avoid freeze-thaw cycles
- Ionic strength: High salt concentrations can reduce viscosity
Regulatory Compliance
HA is approved for use in:
- EU (Annex III exempt — no restriction)
- US FDA (GRAS status)
- China NMPA (approved cosmetic ingredient)
- South Korea MFDS (approved)
SEYE provides full INCI documentation, stability test reports, and challenge test data for all HA-containing formulas.
OEM Applications at SEYE
Our HA product portfolio includes:
- Hyaluronic Acid Hydrating Serum (1.5% Tri-Weight HA Complex)
- Deep Moisture Face Cream (0.3% HA + Ceramide NP)
- Intensive Hydration Ampoule (3% Low MW HA + Niacinamide)
- Hydrating Eye Gel (0.2% HA + Caffeine)
SEYE R&D Team
Senior Formulation Scientist
Part of SEYE's expert team with deep expertise in cosmetic formulation, OEM manufacturing, and global regulatory compliance.
