Quick Comparison
| Hyaluronic Acid | Vitamin K | |
|---|---|---|
| Typical Concentration | Concentrations: 0.1-2%. Higher is not always better — concentrations above 2% can feel sticky and may actually pull moisture FROM skin in dry climates. Multi-molecular weight formulations are preferred. Apply to damp skin and seal with moisturizer. | Concentrations: 1-5% in eye creams and targeted treatments. Apply to under-eye area and areas with visible blood vessels. Results take 4-8 weeks of consistent use. Phytonadione (vitamin K1) is the most common topical form. |
| Application | Topical (serum, cream, mask). Apply to damp skin and layer occlusive on top. Injectable HA fillers are a separate medical category. | Topical (eye cream, serum). Apply gently to under-eye area and areas of concern. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
Hyaluronic Acid
Hyaluronic acid is a glycosaminoglycan (GAG) composed of repeating D-glucuronic acid and N-acetyl-D-glucosamine disaccharides. Its hydroxyl and carboxyl groups create strong hydrogen bonding with water—each molecule binds up to 1000x its weight in water. High molecular weight HA (>1000 kDa) forms a viscoelastic film on the stratum corneum, reducing transepidermal water loss (TEWL). Medium weight (100-1000 kDa) penetrates the upper epidermis. Low molecular weight HA (<100 kDa) reaches the dermis and binds CD44 and RHAMM receptors on fibroblasts, triggering ERK and PI3K signaling that stimulates fibroblast proliferation, hyaluronan synthase (HAS2) expression, and collagen I/III synthesis. Sodium hyaluronate—the salt form—has improved stability and penetration. Multi-weight formulations provide surface hydration and deeper dermal stimulation.
Vitamin K
Vitamin K (phytonadione/K1) is cofactor for gamma-glutamyl carboxylase, which carboxylates glutamic acid residues in clotting factors II, VII, IX, X and proteins S, C — essential for calcium binding and coagulation cascade activation. Topically promotes reabsorption of subcutaneous extravasated blood by activating local clotting cascades that convert leaked hemoglobin to biliverdin and bilirubin for clearance. Strengthens capillary walls, reduces vascular permeability. For vascular dark circles: improves vessel wall integrity, reduces hemosiderin deposition. Supports elastic fiber production through matrix Gla protein carboxylation. Has anti-inflammatory effects. Clinical use: bruising, post-procedure ecchymosis, periorbital vascular hyperpigmentation. Results require 4-8 weeks consistent application.
Risks & Safety
Hyaluronic Acid
Common
Stickiness at high concentrations. In very dry/arid climates, HA can draw moisture from deeper skin layers to the surface where it evaporates.
Serious
None.
Rare
Mild irritation from very low molecular weight HA penetrating too deeply.
Vitamin K
Common
Essentially none — very well-tolerated.
Serious
None documented topically.
Rare
Allergic contact dermatitis.
Full Profiles
Hyaluronic Acid →
The most popular hydrating ingredient in skincare. Hyaluronic acid (HA) is a glycosaminoglycan naturally produced by the body that can hold up to 1,000x its weight in water. In skincare, different molecular weights serve different functions: high molecular weight HA sits on the skin surface forming a moisture barrier, while low molecular weight HA penetrates deeper layers for plumping hydration.
Vitamin K →
A fat-soluble vitamin that supports blood clotting and blood vessel integrity. In skincare, vitamin K is primarily used for dark circles under the eyes (caused by visible blood vessels), bruising, spider veins, and post-procedure redness. It strengthens capillary walls and supports the reabsorption of blood that has leaked from damaged vessels. Often combined with retinol and vitamin C in eye creams.