Here is the exact moment where the hyaluronic acid story looks like it comes crashing down. A ground-breaking 2023 study radioactively labeled the hyaluronic acid in supplements to see if it is absorbed. The study concluded that hyaluronic acid is broken down and is not absorbed in its intact form [1].
So are supplement companies lying to consumers about hyaluronic acid? Not so fast — particularly when factoring in a new human randomized controlled trial published in the journal Scientific Reports in December 2025 [2].
Table of Contents
- What Is Hyaluronic Acid?
- Early Studies on HA Supplements
- Limitations of Previous Research
- The Absorption Question
- The 2025 Study: A New Chapter
- How Does It Actually Work?
- Important Caveats
- The Bottom Line
- References
What Is Hyaluronic Acid?
Hyaluronic acid is a natural compound found especially in the skin, joints, and eyes. It provides crucial structural support in the skin, keeping it plump, hydrated, and smooth.
Unfortunately, levels of hyaluronic acid in the skin slowly decrease with age. Someone at 75 years of age has only a quarter of the hyaluronic acid in their skin compared with someone who is 19 [3].
Early Studies on HA Supplements
There have been some encouraging studies showing that supplementing with hyaluronic acid may help combat this decline. Several smaller studies in Japan focused on whether hyaluronic supplements could improve dry skin. They consistently showed that hyaluronic acid supplements improved skin moisture [4].
Then there is the effect on wrinkles. A small initial study published in 2007 found that hyaluronic supplements taken for 8 weeks reduced wrinkles around the eyes [3].
Several later studies have backed up this finding. A 2021 trial found wrinkles decreased by 18.8% with hyaluronic acid supplements, compared to a non-significant reduction of 2.6% in the placebo group [5].
A larger 2023 study of 129 people again demonstrated skin improvements from hyaluronic acid supplements across multiple areas. Oral administration of hyaluronic acid significantly promoted skin hydration after 2–8 weeks among both young and elderly groups. Skin tone improvement was observed after 4–8 weeks, while an increase in epidermal thickness was noted after 12 weeks [6].
Even though all these results are encouraging, there have been some significant drawbacks with existing studies that introduce some uncertainty.
Limitations of Previous Research
Sample sizes have usually been small, which decreases confidence in the results [2].
Participants have had specific skin conditions — like dry, aged skin — and most have been from countries in Asia. These factors can make it unclear what kind of results might appear in other populations [2].
Some studies have lacked detailed statistical analysis, making it hard to critically evaluate the findings. Many of the key studies are published only in Japanese, which raises accessibility and evaluation issues [2].
There are also important metrics related to skin quality that earlier studies did not measure. These include the extent of water loss through the skin, what is happening with oil production, and changes in skin coloration [2].
Finally, there is the issue of dosing. Most studies have used relatively high doses of hyaluronic acid. There is emerging evidence, however, that substantially lower doses may be effective [2].
The Absorption Question
On top of these limitations, there have also been concerns about absorption. To achieve skin improvements, the goal is to target the rejuvenation of hyaluronic acid in the layers of the skin. So how does hyaluronic acid reach this target?
One very direct route exists. Hyaluronic acid can be injected directly into the skin — a popular cosmetic treatment with reasonably strong evidence behind it. A recent meta-analysis examined 13 studies on the procedure and found that injecting hyaluronic acid causes a significant improvement in facial skin quality [7].
For many people, though, oral supplements are far more accessible. The question is whether hyaluronic acid taken orally can make it to the skin where it is needed.
Initially, there was a strong reason to think the answer would be "no." To understand why, it helps to consider molecular weight. Structurally, hyaluronic acid is like a chain built from simple links — and just like a chain, molecules of hyaluronic acid can be of different lengths. Long ones are heavy; they have a high molecular weight. Short ones have a low molecular weight.
Scientists originally believed high molecular weight forms of hyaluronic acid would be best for oral supplements. The idea was that they would be more stable and less likely to be immediately broken down through digestion. These longer chains were also thought to have an anti-inflammatory effect, with the hope that more would be able to make it intact to sites like the skin where it would be useful.
But there is a catch-22 here. Those high molecular weight forms have big molecules — potentially too big to pass through the intestinal wall. If so, the supplement would simply pass through the digestive system without providing any benefit.
Early experiments were encouraging. A groundbreaking study published in 2009 involved oral hyaluronic acid supplementation in rats and dogs, using a high molecular weight form tagged with a radioactive substance so researchers could trace where it went. They found evidence that it made its way directly to connective tissue throughout the bodies of the animals [8]. It appeared to stay intact and pass through the gut barrier.
Another study, citing human experiments, agreed with this conclusion — that hyaluronic acid in an oral supplement can be absorbed whole and distributed to the skin [9].
Then came the 2023 study that challenged these assumptions. It revealed that the earlier understanding of how hyaluronic acid worked as a supplement was, in important respects, incorrect.
First, high molecular weight hyaluronic acid is not absorbed at all [1].
That does not mean nothing gets absorbed. The story is more complex. High molecular weight hyaluronic acid first has to be broken down in the stomach, where those long chains are chopped into shorter lengths.
These shorter lengths — called middle-weight hyaluronic acid — are not absorbed either. In this study, researchers used two groups of mice: one with normal gut bacteria and one with no gut bacteria. In the bacteria-free group, no hyaluronic acid was absorbed at all; it was broken down in the stomach and passed through.
In the group with normal bacteria, things went differently. The medium-weight hyaluronic acid was broken down even further by gut bacteria — and this final breakdown step yields a form that can be absorbed [1].
So absorbing hyaluronic acid is a bit like pulling apart a LEGO structure. The digestive system breaks down the long chains of high-molecular-weight hyaluronic acid into smaller pieces — just as one might break down a LEGO castle into individual bricks before building something else. These smaller pieces can then be absorbed and used by the body.
However, even after this process, the bioavailability of hyaluronic acid remains very low — around just 0.2% [1].
The 2025 Study: A New Chapter
A puzzle emerges from the existing research. Some studies show effectiveness. But doubts are easy to hold — because other studies show hyaluronic acid is not directly absorbed, leaving the mechanism unclear. And, as described above, existing studies have meaningful limitations.
That is where the new 2025 study enters the picture. The researchers set out to make a decisive contribution to the literature. It is a double-blind randomized controlled trial that included 150 participants, used a broad set of objective measures of skin parameters, and ran for 12 weeks. Crucially, the data comes from a central European population — a different demographic from most earlier studies [2].
The trial analyzed the impact of hyaluronic acid supplements at two different doses across a comprehensive set of metrics: facial hydration, water loss through the skin, oil levels, elasticity, wrinkle depth, skin gloss, coloration, thickness, density, red patches, and pore size — all assessed at baseline and every two weeks during the study [2].
The primary outcome was skin hydration on the cheek after three months of supplements. In the group taking the higher dose of 120 mg/day of sodium hyaluronate, hydration was boosted by 11.5% compared to placebo. At the lower dose of 60 mg/day, the moisture increase was 9.1% [2].
Improvements appeared in other areas too. There were significant reductions in water loss through the skin, oil production, and the depth of wrinkles around the eye. The researchers also found increases in skin thickness, density, and the presence of moisture-boosting molecules in the upper layer of the skin [2].
Coloration, pore size, and skin gloss were not significantly affected [2].
Across the board, the impact of the lower dose (60 mg) was similar in direction to the higher dose, but more modest in magnitude [2].
A key takeaway: the results of earlier studies are confirmed. Oral hyaluronic acid supplements drive measurable improvements in objective skin quality parameters, even in a rigorously designed trial in a new population.
How Does It Actually Work?
The 2025 study also provides insight into the crucial question of mechanism. This same research team had previously shown that at most a negligible amount of the broken-down fragments of hyaluronic acid actually reach the skin. Its mechanism of action therefore appears to be indirect rather than direct [2].
The authors propose three potential pathways.
One possibility is that hyaluronic acid supplements work by influencing the gut microbiome. Hyaluronic acid has been shown to promote the growth of bacteria that produce short-chain fatty acids. These fatty acids, in turn, can influence the skin through anti-inflammatory effects, promoting healthy skin cell development, and enhancing the skin's barrier function [2].
A second possibility is that hyaluronic acid or its components bind to receptors in the gut that promote systemic anti-inflammatory effects throughout the body [2].
A third pathway, seen in mouse experiments, is that hyaluronic acid supplements can upregulate the production of both collagen and hyaluronic acid within the skin itself [2].
Though the precise details remain uncertain, the evidence suggests that hyaluronic acid may act through some combination of these — and possibly other — indirect pathways to produce the consistent skin benefits seen across multiple studies.
Important Caveats
Some important caveats are worth noting. The 2025 research was funded by a company that manufactures hyaluronic acid, and several of the authors are employees [2]. That does not automatically make the findings suspect — industry-funded trials can be rigorously designed — but it is a factor worth keeping in mind when interpreting the results.
Also, the absolute effect sizes with hyaluronic acid are modest. That is what one would expect from a single supplement; it is only ever going to be one part of a more comprehensive approach to skin health. Longer-term trials — beyond the 12 weeks studied — will be important for understanding whether benefits persist and whether there are any effects on skin parameters not yet measured.
The Bottom Line
Questions remain about ideal dosing, long-term benefits, and the exact mechanisms involved. For now, though, hyaluronic acid has an excellent safety profile and a body of study evidence that just got stronger — including a well-designed, 150-person double-blind RCT showing meaningful improvements in skin hydration, wrinkle depth, and skin thickness.
One key practical note from the research: the evidence to date suggests there is no additional benefit from expensive high molecular weight hyaluronic acid. It gets broken down regardless, and the benefits it produces are indirect. Low molecular weight sodium hyaluronate — the form used at effective doses in the research — is what the studies support.
From the MicroVitamin range
MicroVitamin+ Powder includes 200 mg of low molecular weight sodium hyaluronate — the same form studied in the clinical research — alongside collagen, creatine, and 24 other evidence-based nutrients. MicroVitamin+ Powder.
References
1. https://www.sciencedirect.com/science/article/abs/pii/S0144861723003454
2. https://www.nature.com/articles/s41598-025-32758-5
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5522662/
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC4110621/
5. https://pubmed.ncbi.nlm.nih.gov/34933842/
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10661223/
7. https://pmc.ncbi.nlm.nih.gov/articles/PMC10082573/
