What is hyaluronic acid?
Hyaluronic acid is one of the main components of the extracellular matrix. It binds with chondroitin and keratan sulphate, and forms crosslinks with collagen fibres. It is a glycosaminoglycan made in the synoviocytes, fibroblasts and chondrocytes, and plays an important role in the biomechanical properties of connective tissue. It has excellent viscoelastic properties and a high capacity for water retention, enabling it to lubricate, absorb shock, maintain the water balance, and stabilise the structure of joints. 1
The importance of taking oral hyaluronic acid
The concentration of hyaluronic acid in our bodies decreases with age. Hyaluronic acid has been safely used in a number of treatments in dogs, horses, and humans. When taken orally, it is very well absorbed in the intestines. One study showed that it was found in all tissues from 15 minutes after ingestion and remained for 48 hours, especially concentrated in the joints, vertebrae, and salivary gland tissue.3
There are several types of hyaluronic acid, distinguished by their molecular weight (size). Some studies have showed that the types with a higher molecular weight (found naturally in our bodies) had a greater impact, due in particular to their superior moisture retention and stronger anti-inflammatory effect,4 but other studies show a powerful effect regardless of molecular weight.5,6
Antioxidant, anti-inflammatory, and pain-killing properties
Chronic inflammation and uncontrolled oxidative stress can have harmful effects on your health and speed up tissue degeneration. These phenomena can disrupt the functioning of mitochondria, which produce energy for cells. They will also increase the production of proteolytic enzymes (protein-splitting enzymes like MMPs, which break down collagen). This causes molecules in the extracellular matrix to deteriorate and leads to the death of certain tissue cells (chondrocytes, for example).
Hyaluronic acid protects against inflammation and oxidative stress. Taking it reduces the production of nitric oxide and free radicals, thereby reducing oxidative stress.7 The presence of hyaluronic acid also helps to increase antioxidant synthesis.1 It also reduces the production of pro-inflammatory mediators, such as cytokines, bradykinin and prostaglandin, helping to minimise inflammation. 1
As it interacts with nerve endings (which become less sensitive and therefore transmit less pain), hyaluronic acid also has analgesic properties.2
The structural functions of hyaluronic acid in our tissue
As hyaluronic acid is an essential molecule for the structure of our connective tissue, its presence helps to keep this tissue in good working order. For example, it increases the synthesis of glycosaminoglycans and collagen, strengthening the tissue’s structure. It will also inhibit the production of catabolic enzymes (such as MMPs, which break down collagen).
Hyaluronic acid will also interact with various cells and molecules in the extracellular matrix, and can regulate cell behaviour (proliferation, cell survival, inflammation, anabolism, etc.). In particular, its presence will restore the metabolism, proliferation and functioning of fibroblasts, which produce various molecules that support the tissue.
The benefits of taking hyaluronic acid for the joints
The benefits of hyaluronic acid have generally been observed in the joints. It increases joint mobility and function, and reduces stiffness and pain. In addition, it increases the body’s own synthesis of proteoglycans, collagen and hyaluronic acid by the synoviocytes and chondrocytes, boosting the regeneration of cartilage. It also inhibits osteoclasts, which reabsorb the sub-chondral bone and weaken the joints. It will also increase the density and vitality of chondrocytes, which produce the molecules needed for healthy, functional cartilage.
In the case of osteoarthritis, levels of inflammation and oxidation are elevated, which promotes cellular death and damages the cartilage, bones and synovial fluid. Taking hyaluronic acid helps restore the properties of synovial fluid and joint cell metabolism. Several studies have shown that increasing the quantity of hyaluronic acid in joints leads to improved joint function, and reduced pain and stiffness. This can be seen in lowered VAS, WOMAC and Lesquesne scores, which signify an improvement and slowing down of disease progression.1,6,8, 9
Hyaluronic acid, a major asset in wound healing
Healing a wound involves a series of complex remodelling processes in the extracellular matrix. Hyaluronic acid will therefore regulate the coordination of the various stages involved. By acting on the tissue’s micro-environment and binding to cell receptors, it can influence the behaviour and functions of cells, and also gene expression.1,10–12 In the skin and mucous membranes, hyaluronic acid will help to encourage tissue revascularisation, granulation and re-epithelialisation. The proliferation of fibroblasts and keratinocytes, and the synthesis of collagen fibres will also be increased. It will also regulate localised inflammation. Its properties are therefore very important in wound healing.
An excellent moisturiser
Thanks to its viscoelastic and water-retaining properties, hyaluronic acid is a very good moisturiser for all types of tissue.
Taking hyaluronic acid brings clear benefits for the health of your skin. A 6-week course has been shown to increase skin hydration by 8%, an effect that lasts for 2 weeks after the end of treatment.13
In terms of eye health, for example, taking hyaluronic acid can provide long-lasting rehydration for dry eyes and increase tear film, which reduces irritation and friction when blinking. It also improves healing of the eyes after surgery.1
Hyaluronic acid, an outstanding choice
Taking oral hyaluronic acid brings numerous benefits to our bodies. Its moisturising, antioxidant and anti-inflammatory powers make it an invaluable partner in the treatment of various conditions, especially for osteoarthritis and skin wounds.
- Gupta, R. C., Lall, R., Srivastava, A. & Sinha, A. Hyaluronic acid: Molecular mechanisms and therapeutic trajectory. Frontiers in Veterinary Science 6, (2019).
- Moreland, L. W. Intra-articular hyaluronan (hyaluronic acid) and hylans for the treatment of osteoarthritis: mechanisms of action. Arthritis Research & Therapy 5, 54 (2003).
- Balogh, L. et al. Absorption, uptake and tissue affinity of high-molecular-weight hyaluronan after oral administration in rats and dogs. Journal of Agricultural and Food Chemistry 56, 10582–10593 (2008).
- Migliore, A., Giovannangeli, F., Granata, M. & Laganà, B. Hylan G-F 20: Review of its safety and efficacy in the management of joint pain in osteoarthritis. Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders 3, 55–68 (2010).
- Ghosh, P. & Guidolin, D. Potential mechanism of action of intra-articular hyaluronan therapy in osteoarthritis: Are the effects molecular weight dependent? Seminars in Arthritis and Rheumatism 32, 10–37 (2002).
- Tikiz, C., Ünlü, Z., Şener, A., Efe, M. & Tüzün, Ç. Comparison of the efficacy of lower and higher molecular weight viscosupplementation in the treatment of hip osteoarthritis. Clinical Rheumatology 24, 244–250 (2005).
- Nelson, F. R. et al. The effects of an oral preparation containing hyaluronic acid (Oralvisc®) on obese knee osteoarthritis patients determined by pain, function, bradykinin, leptin, inflammatory cytokines, and heavy water analyses. Rheumatology International 35, 43–52 (2015).
- Gigis, I., Fotiadis, E., Nenopoulos, A., Tsitas, K. & Hatzokos, I. Comparison of two different molecular weight intra-articular injections of hyaluronic acid for the treatment of knee osteoarthritis. Hippokratia 20, 26–31 (2016).
- Tashiro, T. et al. Oral administration of polymer hyaluronic acid alleviates symptoms of knee osteoarthritis: A double-blind, placebo-controlled study over a 12-month period. The Scientific World Journal 2012, (2012).
- Oksala, O. et al. Expression of proteoglycans and hyaluronan during wound healing. Journal of Histochemistry & Cytochemistry 43, 125–135 (1995).
- CHEN, W. Y. J. & ABATANGELO, G. Functions of hyaluronan in wound repair. Wound Repair and Regeneration 7, 79–89 (1999).
- Olczyk, P., Komosińska-Vassev, K., Winsz-Szczotka, K., Kuźnik-Trocha, K. & Olczyk, K. [Hyaluronan: structure, metabolism, functions, and role in wound healing]. Postepy higieny i medycyny doswiadczalnej (Online) 62, 651–9 (2008).
- Kawada, C. et al. Ingested hyaluronan moisturizes dry skin. Nutrition Journal 13, 1–9 (2014).