Hyaluronic acid is now widely available as the miracle ingredient in serums, creams and injectable fillers. But what is it, where did its reputation as the answer to youthful skin come from, and does it really live up to the hype? In this post we look at the science behind hyaluronic acid and the story that made it famous. We also ask what the evidence actually shows about turning back the clock.
What is Hyaluronic Acid?
Hyaluronic acid is a naturally occurring molecule called a glycosaminoglycan, found in the middle layer of our skin. It has an important structural role, essentially filling the space between cells and giving skin its volume and firmness. Research shows that hyaluronic acid helps maintain skin elasticity, has antibacterial and anti-inflammatory functions, supports collagen production and works as an antioxidant. Most of its appeal comes down to one remarkable property. A single hyaluronic acid molecule can hold up to 1,000 times its own weight in water. This is what makes it such an effective moisturiser.
Where Did the “Secret to Youth” Idea Come From?
The reputation of hyaluronic acid as a youth ingredient took off in the early 2000s. This was after a reporter visited the Japanese village of Yuzurihara and wrote about the longevity and youthful appearance of its elderly residents. Many villagers in their 80s and 90s had smooth skin, thick hair and flexible joints, and remained very active. The town’s doctor, Dr Toyosuke Komori, had a theory. He suggested their low-iron, vegetable-based diet (rich in soya and tofu) promoted hyaluronic acid levels in the body. It’s a charming story, though the link between everyday diet and the skin’s own hyaluronic acid is largely anecdotal rather than proven.
What is clear is that, as we age, the body produces less hyaluronic acid. This contributes to a loss of volume and firmness, leading to sagging skin, thinner lips and wrinkles. It is estimated that by our mid-40s, our hyaluronic acid synthesis is roughly half of what the body needs.
Can Your Diet or Supplements Boost Hyaluronic Acid?
The supposed source of hyaluronic acid in Yuzurihara is the local diet. This is low in iron and based on vegetables like satoimo (a sticky potato) and imoji (a potato root), along with tofu and soya. Outside Japan, foods such as leafy greens, root vegetables and soy products may be easier to find. Homemade soups and broths made from animal bones, connective tissue and skin are another popular source. Getting meaningful amounts from food alone is far from certain, though, and rests mainly on observation rather than controlled studies.
Oral hyaluronic acid supplements are a different matter, and the evidence here is more encouraging than many people expect. A 2025 meta-analysis of seven randomised controlled trials found that daily oral hyaluronic acid significantly improved skin hydration, elasticity and wrinkle depth. Individual trials point the same way. One study of 129 people reported better hydration within 2 to 8 weeks in both younger and older participants. It’s worth keeping some perspective, though. These trials tend to be small and short. Oral hyaluronic acid is also broken down in the gut rather than absorbed whole, so it most likely works indirectly. Even so, the supplement evidence is stronger than the case for diet alone.
Does Topical Hyaluronic Acid Actually Work?
Applying hyaluronic acid topically is the most accessible route, and there is good evidence that it improves the skin’s surface. A 2011 study found that 0.1% hyaluronic acid creams significantly improved skin hydration and elasticity after 60 days. The low-molecular-weight version also reduced wrinkle depth.
That last point comes down to molecule size, which is where a lot of marketing claims fall apart. Molecular weight determines how far hyaluronic acid travels. Low-molecular-weight hyaluronic acid (roughly 20 to 300 kDa) can pass through the outer layer of the skin. By contrast, high-molecular-weight hyaluronic acid largely sits on the surface. The surface effect still hydrates and plumps by drawing in water, but only the smaller forms penetrate more deeply. For a full guide on choosing and layering products, see our post on the benefits of hyaluronic acid for skin.
What About Fillers & Skin Boosters?
Placing hyaluronic acid directly into the skin gives the most immediate and visible results, which is why injectable treatments dominate the youth-restoring conversation. Injectable dermal fillers plump thin lips and smooth facial wrinkles, folds and hollows, including marionette lines and smile lines. Skin boosters (such as Profhilo) are a related treatment. They use injected hyaluronic acid to hydrate and improve skin quality across a whole area, rather than add volume to one spot. Small clinical trials of intradermal hyaluronic acid have shown improvements in skin hydration, which supports the idea behind these treatments.
Because hyaluronic acid occurs naturally in the body, injected fillers integrate well into tissue. Their effects are also reversible with an enzyme called hyaluronidase. The results are temporary and typically last 6 to 12 months as the filler gradually breaks down. Both fillers and skin boosters are in-clinic procedures performed by a trained practitioner, rather than something you can do at home.
So is hyaluronic acid really the secret to youth? Not on its own. No single ingredient can stop ageing, which is a complex process driven by many factors. Hyaluronic acid is a brilliant hydrator that can make skin look smoother, plumper and more radiant. However, it works best as one part of a wider routine alongside sun protection, a good diet and other proven actives like retinoids. Look after your skin, wear an SPF over 30 and avoid smoking, and treat hyaluronic acid as a valuable tool rather than a magic bullet.
At City Skin Clinic, we are passionate about personalised skincare. Our online clinic offers safe and effective treatments using ingredients like tretinoin and hydroquinone where appropriate. Our doctors treat skin conditions like acne, hyperpigmentation, melasma and skin ageing. To start your personalised plan, book a virtual video consultation or use our online consultation form. The journey towards great skin and hair starts here.
This article is intended for general informational purposes only and is not a substitute for medical advice, diagnosis or treatment. Always consult a qualified medical professional with any concerns about your skin or treatment options.
