Here is the exact moment where the hyaluronic acid story to treat skin wrinkles looks like it comes crashing down. A ground-breaking 2023 study radioactively labeled the hyaluronic acid in supplements to see if it's 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 you about hyaluronic acid? Not so fast, particularly when we factor 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 our 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 as 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. For instance, there were 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. For instance, a 2021 trial found wrinkles decreased by 18.8% with hyaluronic acid supplements. This compared to a non-significant reduction of 2.6% in the placebo group [5].
Finally, a larger 2023 study of 129 people again demonstrated skin improvements from hyaluronic acid supplements in multiple areas. Oral administration of HA 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].
But 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 we might see in other populations [2].
Sometimes studies have lacked a detailed statistical analysis, making it hard to critically evaluate the findings. Many of the key studies are published only in Japanese, which means accessibility and evaluation is an issue [2].
And there are also important metrics related to skin quality that earlier studies haven't checked. These include the extent of water loss through the skin, what's happening with oil production, and changes in skin coloration [2].
Finally, there's the issue of dosing. Most studies have used relatively high doses of hyaluronic acid. There's emerging evidence, though, that substantially lower doses might be effective [2].
The Absorption Question
On top of these limitations, there have also been concerns about absorption. To see skin improvements, we want to target the rejuvenation of hyaluronic acid in the layers of the skin. So how do we make sure hyaluronic acid reaches this target?
We can take a very direct route. Hyaluronic acid can be injected directly into the skin. It's a popular cosmetic treatment, and the evidence suggests it probably works. One recent meta-analysis examined 13 studies on the procedure. The authors found injecting hyaluronic acid causes a significant improvement in facial skin quality [7].
But we're interested in oral supplements since it's a lot more accessible for many of us. So the question is whether the hyaluronic acid we swallow can make it to the skin where it's needed.
Initially, there was a big reason to think the answer would be "no." To see why, we need to talk about molecular weight. A molecule is a collection of atoms bonded together in a certain way. The weight is about how big this collection is. 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 thought high molecular weight forms of hyaluronic acid would be best for oral supplements. The idea was that they'd be more stable and less likely to be immediately broken down through digestion. Plus, they may have an anti-inflammatory effect. The hope was that more would be able to make it intact to sites like the skin where it would be useful.
But there's a catch-22 here. Those high molecular weight forms of hyaluronic acid had big molecules. Maybe too big to pass through the intestinal wall. And if that proved to be the case, the fear was that the supplement would just pass through the digestive system without providing any benefits.
We just didn't know for sure what would happen until we did some research.
Early experiments were encouraging. A groundbreaking study was published in 2009. It involved oral hyaluronic acid supplementation in rats and dogs. Researchers used a high molecular weight form. They tagged hyaluronic acid with a radioactive substance so they could see where it went. They found evidence it made its way directly to connective tissue throughout the bodies of the animals [8]. It seemed to stay intact and make it through the gut barrier.
Another study, citing human experiments, agreed with this conclusion. Hyaluronic acid in an oral supplement looks like it is absorbed whole and distributed to the skin [9].
But this brings us back to that 2023 study I mentioned at the outset. It revealed our assumptions about how hyaluronic acid worked as a supplement were all wrong.
First, high molecular weight hyaluronic acid isn't absorbed at all [1].
That doesn't mean nothing gets absorbed. But the story is more complex. The high molecular weight hyaluronic acid first has to be broken down. This happens in the stomach, as those long chains get chopped into shorter lengths.
But here's where it gets interesting. These shorter lengths, called middle-weight hyaluronic acid, aren't absorbed, either. For this study, researchers used two kinds of mice. One group had normal gut bacteria, and another group had no gut bacteria. In the no bacteria group, no hyaluronic acid was absorbed. It was broken down in the stomach and then just passed through.
In the group with normal bacteria, however, things went differently. Here the medium-weight hyaluronic acid got broken down even further by gut bacteria. And this finally gets us to a form that can be absorbed [1].
So it turns out absorbing hyaluronic acid is like pulling apart a LEGO structure. The digestive system breaks down the long chains of high-molecular-weight hyaluronic acid into smaller pieces. It's just like you 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 is still very low — around just 0.2% [1].
The 2025 Study: A New Chapter
So there's a bit of a puzzle. We have some studies showing effectiveness. But it's easy to have doubts. Because we also have studies showing hyaluronic acid isn't directly absorbed, so it isn't clear how it is driving benefits. And, as we've seen above, there are some limitations with existing studies.
So that's where the new study enters the picture. They set out to make a decisive new contribution to the literature. It's a double-blind randomized controlled trial. It included 150 participants, used a broad set of objective measures of skin parameters, and lasted 12 weeks. And we're getting data from a different population — in central Europe [2].
They analyzed the impact of hyaluronic acid supplements at 2 different doses by looking at an impressive number of metrics. They checked facial hydration, water loss through the skin, oil levels, elasticity, wrinkle depth, skin gloss, coloration, thickness, density, red patches, and pore size at baseline and every 2 weeks during the study [2].
The primary outcome was skin hydration on the cheek after 3 months of supplements. It was boosted by 11.5% compared to placebo in the group taking the higher dose of 120 mg/day of sodium hyaluronate. At the lower dose, the moisture increase was 9.1% [2].
Improvements showed up in other areas, too. There were significant reductions in water loss, oil production, and the depth of wrinkles around the eye. They 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 weren't affected [2].
Across the board, the impact of the lower dose of hyaluronic acid, at 60 mg, was similar to the higher dose but more modest [2].
So a big takeaway from this study is that the results of earlier studies are confirmed. Hyaluronic acid supplements drive measurable improvements in parameters of skin quality.
How Does It Actually Work?
But the study also gives us a bit more insight into the crucial question of how hyaluronic acid is able to improve the skin. It was this same team of researchers whose earlier study showed that at most a negligible amount of the broken down pieces of hyaluronic acid make it to the skin. Its mechanism of action appears to be indirect, rather than direct [2].
How exactly does it work? The authors propose 3 potential pathways.
One possibility is that hyaluronic acid supplements work by impacting 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 impact the skin through anti-inflammatory effects, promoting healthy skin cell development, and enhancing the skin's barrier function [2].
Another possibility is that hyaluronic acid or its components bind to receptors in the gut that help promote systemic anti-inflammatory effects [2].
Finally, experiments with mice have shown hyaluronic acid supplements can turn up the production of collagen and hyaluronic acid in the skin [2].
Though we're still uncertain about the details, it seems hyaluronic acid may be acting through these and possibly other pathways to produce the very real benefits for the skin studies consistently find.
Important Caveats
Some important caveats. The research was funded by a company that makes hyaluronic acid, and several authors are employees [2]. That doesn't automatically make the findings suspect, but it's good to keep in mind.
Also, the absolute effect sizes with hyaluronic acid are modest. But that's what we should expect; a supplement like this is only ever going to be one part of a more comprehensive approach to skin health.
The Bottom Line
Questions remain about ideal dosing, long-term benefits, and the mechanisms involved. For now, though, hyaluronic acid has an excellent safety profile and encouraging study evidence of benefit that just got stronger. That's why I include it in MicroVitamin and MicroVitamin+ Powder.
And there's something worth noticing, by the way. The evidence we have to this point suggests there's no benefit with expensive high molecular weight hyaluronic acid. It just gets broken down anyway and the effects it produces are indirect, as we've seen. I use low molecular weight sodium hyaluronate.
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/
