Hyaluronic Acid Serum mg

Hyaluronic acid serum: dosage and molecular weight

Hyaluronic acid (HA) is a glycosaminoglycan the human body makes on its own, and you'll find it in skin, joint cartilage, the eye's vitreous humor and synovial fluid. In serum form the cosmetic version usually sits at 1–2% (mass/volume) in aqueous solution. You've probably seen the big names: Hada Labo Tokyo Gokujyun Premium Lotion, The Ordinary Hyaluronic Acid 2% + B5, Vichy Minéral 89. As a humectant, each gram of HA can hold up to 1000 g of water, pulling moisture from the air and the dermis into the stratum corneum.

The detail that matters most is molecular weight (MW). High-MW HA (> 1.000 kDa) stays up on the surface, where it forms a smoothing film and plumps the skin right away. Low-MW HA (10–50 kDa) gets deeper into the epidermis and hydrates for longer, although some studies suggest very low MW can set off an inflammatory response. The better formulations blend several molecular weights for a “multi-depth” effect. On labels you'll mostly see sodium hyaluronate (the sodium salt), since it holds up better than free HA.

Applications

HA serums hydrate without that greasy feel, fill in fine dehydration lines, calm skin after procedures (laser, peels, microneedling) and suit every skin type, acne-prone included. Critical application rule: put it on damp skin (right after cleansing, while there's still water on the surface), then seal with moisturizer. On dry skin in low-humidity environments (< 40% RH, dry winter, air conditioning), HA can do the reverse and draw water from the deep dermis up to the surface, leaving skin tight and dehydrated. Beyond skincare, HA shows up in oral and intra-articular supplements for osteoarthritis and in cosmetic dermatology fillers (Restylane, Juvederm) given by intradermal injection.

FAQ

Hyaluronic acid or glycerin? They're both humectants. Glycerin is the smaller molecule and gets in more easily, while HA holds more water per molecule and gives that immediate “plump” look. Using both in the same routine works fine.

Can I use it daily? Yes, morning and night, always on damp skin and sealed with moisturizer. It plays nice with almost any active you throw at it (vitamin C, retinol, niacinamide, AHAs).

Does oral HA work? Recent meta-analyses (2021–2023) found a modest bump in skin hydration with oral doses of 120–240 mg/day over 8–12 weeks, well short of what topical application does. For joints, the evidence behind intra-articular injection is much stronger than the oral route.