Oral Hyaluronic Acid Shows 8.7% Hydration Gain in 150-Person RCT
Hyaluronic acid is well-established as a topical skincare ingredient. The case for taking it orally is newer and, until recently, less backed by large-scale evidence. A study published in Scientific Reports in December 2025 adds meaningful weight to that case, with a 150-person randomized trial measuring skin hydration, barrier function, and elasticity over 12 weeks.
Study Design at a Glance
Researchers recruited 150 healthy Caucasian adults and assigned them to one of three groups: SH60 (60mg sodium hyaluronate per day), SH120 (120mg per day), or placebo. The sodium hyaluronate used was high molecular weight at 1.8 MDa (megadaltons), a size commonly associated with barrier-supporting and moisture-retaining activity in the dermis, the deeper structural layer of skin.
The trial was registered as NCT07065110 and ran for 12 weeks, with subjective skin evaluations collected every two weeks alongside objective measurements. The scope of what was measured was notably broad: facial hydration, TEWL (trans-epidermal water loss, a proxy for barrier integrity), sebum production, elasticity, wrinkle depth, skin gloss, epidermal thickness, dermal density, and pore size. Researchers also analyzed NMF (natural moisturizing factor, the collection of amino acids and organic acids that skin produces to keep itself hydrated) from forearm skin samples using LC-MS/MS, a precision technique that separates compounds by molecular mass.
The Numbers
At the three-month mark, both supplemented groups showed statistically significant improvements versus placebo in forehead hydration: +8.7% for the 60mg group and +7.2% for the 120mg group. The slightly higher figure in the lower-dose group reflects normal statistical distribution across individuals rather than a dose-response reversal.
The elasticity data was equally notable. The viscous component of skin elasticity (R6, a measure of how well skin recovers after being compressed or stretched) was significantly higher in both supplemented groups compared to placebo at 12 weeks. This suggests that the benefit goes beyond surface hydration, pointing to changes in the structural quality of skin.
Why Oral Delivery Works Differently Than Topical
Topical hyaluronic acid sits on or just below the skin surface, drawing ambient moisture into the upper layers. Oral hyaluronic acid takes a different route entirely. Because it breaks down during digestion, it doesn’t reach the dermis intact. Instead, the fragments produced during digestion are thought to work through two pathways: stimulating fibroblasts (the cells responsible for producing hyaluronic acid and collagen in the dermis) to increase their own output, and supporting the gut-skin axis, the bidirectional relationship between intestinal health and skin condition.
The NMF measurement in this trial addresses the second pathway more directly. NMF is produced by the uppermost skin layer as dead cells break down, releasing compounds that keep the surface hydrated. Changes in NMF composition suggest that oral supplementation may be influencing skin biochemistry from within, not just adding moisture to an existing structure.
Context and Caveats
A 150-person randomized double-blind trial is a high bar for skin supplement research, where studies with 30 to 50 participants are common. The design gives the findings more credibility than most in this category.
The limitation to note is that all participants were Caucasian adults. Skin hydration baselines, melanin distribution, and gut microbiome composition vary across populations, which means these specific percentages may not translate directly to Asian or other demographic groups. Expanded trials including diverse populations would strengthen the generalizability of these results.
For now, the evidence points to 60mg daily as an effective starting dose, with 12 weeks as the timeframe needed to see measurable changes in both hydration and skin structure.