What is glucosamine?

Glucosamine belongs to the class of amino sugars. Chemically it only differs from the glucose molecule by one amino group, which is not present in glucose.

In chemistry, an amino group is a functional group, which includes a nitrogen atom and two hydrogen atoms. An organic compound that contains an amino group is called an amine, as in glucosamine.

A large part of joint cartilage is composed of various glucosamine compounds. Glucosamine therefore plays a major part in the protection of joint cartilage. The effect of additional dietary glucosamine on arthritic changes in joints is intensively under examination.

In order to ensure the chemical stability of glucosamine and to improve its uptake in the body, it is frequently consumed in the chemical form of either glucosamine sulphate or glucosamine hydrochloride.

TIP 1: Glucosamine sulphate is preferable over glucosamine hydrochloride, because it provides the joint with more sulphur (sulphate).

Currently, glucosamine is one of the most promising natural substances in the support of healthy joints. It is also naturally made in the body, which is why very few, if any, side effects are expected as a result of taking glucosamine. In the human body, glucosamine plays an important role in the development of supporting and connective tissue, which includes the joint cartilage. Glucosamine also supports the production of mucous substances and secretions.

Glucosamine for pain relief and cartilage development

Glucosamine is thought to relieve pain and inflammation and help in the formation of new cartilage tissue. This has been confirmed by many orthopaedists in practice.

However, joint cartilage heals very slowly. While skin is regenerated in around seven days, even small amounts of damaged cartilage requires two to three months to recover. As a result, clinical studies tend to last a minimum of six to eighteen months. Several studies have shown positive effects on patients with osteoarthritis or arthritis. And in addition to this, there have been some very promising approaches in which glucosamine has been combined with other substances such as omega-3 fatty acids and chondroitin.

Although pain relief has often been observed in association with glucosamine, no studies have been able to conclusively prove the regeneration of joint cartilage through glucosamine.

This is likely due to two reasons:

1. The exact condition and thickness of the cartilage can only be measured using expensive procedures and
2. the actual regeneration takes several years. Since glucosamine is not a nutrient protected by patents, there is no economic incentive to produce evidence, which is likely very expensive.

We present here a number of clinical studies on glucosamine sulphate and its effects on pain and mobility in osteoarthritis.

Studies on glucosamine

Glucosamine: to be taken alone or in combination with anti-inflammatory drugs?

In 2012 Selvan and colleagues tested the influence of glucosamine sulphate and a combination of glucosamine sulphate with anti-inflammatory drugs. Their subjects suffered from mild to moderate osteoarthritis ¹. In total, 43 participants were given glucosamine sulphate, and a further 39 participants were treated with the combination therapy. All patients were treated for 30 days, and were subsequently assessed for a further three months.

Interestingly, mobility of the affected joints improved in both groups and in general the subjects reported that they felt less pain. As expected, the effect on the level of pain (reduction) felt was greater in the group given the combination therapy. Here the painkillers used specifically targeted and reduced the severe inflammation. This reduced the major swellings, which increased the mobility of the joints. If less inflammation occurs in a joint, the pain is naturally reduced.

As natural anti-inflammatories, omega-3 fatty acids, vitamin E, pine bark extract and willow extract are particularly effective. They complement glucosamine very well.

Glucosamine inhibits inflammation

If glucosamine is used at an early stage and over a long period of time, it can potentially reduce the need to take anti-inflammatory medication (NSAIDs). Importantly, this means that the side effects of pain killers are reduced. Ultimately, this improves the quality of life of those affected.

Interestingly, glucosamine itself seems to have a weak anti-inflammatory effect. As a consequence, it reduces inflammation and swelling. This could possibly contribute to joint damage progressing at a much slower rate.

Glucosamine and chondroitin are effective treatments in cases of severe osteoarthritis

A French study was conducted in 2006 involving more than 1,500 patients with osteoarthritis of the knee. This study investigated the impact of various osteoarthritis treatments on the different patient complaints²:

• Glucosamine sulphate
• Chondroitin sulphate
• A combination of glucosamine and chondroitin
• Painkiller (celecoxib)

In cases of mild osteoarthritis, the difference between glucosamine and placebo treatment was only small. However, patients with more severe osteoarthritis had statistically significant improvements compared to the placebo (the results were clearly measurable and did not occur by chance). 70% of patients that were given the combination preparation of glucosamine and chondroitin had less pain and better mobility.

Effectiveness of glucosamine sulphate in combination with other substances

Glucosamine sulphate affects the pain in the joints and also down the progression of arthritis. Very frequently, however, results differ between experiments in cell cultures and studies in people.

The direct comparison between the quality individual papers is further complicated by the use of different glucosamine dosages and different measurement systems.

Very generally it can be said that glucosamine offers pain relief particularly in cases of mild pain ³.

Combination with Omega-3 and vitamins is recommended

The combination of glucosamine with other substances frequently leads to an altered effect. For example, when glucosamine sulphate is administered in combination with omega-3 fatty acids or vitamins, its effect seems to be stronger ⁴. Similarly, the same effect has also been described for glucosamine sulphate and chondroitin.

The nutrient combination is therefore consistently more effective than the individual substance ⁵.

ALSO CRITICS OF GLUCOSAMINE PRESENT NO ALTERNATIVES

There are also some clinical studies, which could not show any evidence of the effectiveness of glucosamine. A review paper by Burdett and McNeil in 2012 takes a critical view of the previous studies investigating the effects of glucosamine sulphate in patients with osteoarthritis ⁶.

The authors specifically point out that there are clearly promising in-vitro (laboratory) experiments, but the effectiveness in humans (in-vivo) is very different.

Very often, a modified study design means that the work cannot be directly compared with other investigations. Perhaps most importantly, the actual mechanism of how glucosamine works in the cartilage continues to remain unknown.

The two scientists concluded that glucosamine sulphate may at best cause a mild improvement in pain. However, they do not offer an alternative form of medication instead. The bottom line remains: a product that is consistently able to stop and reverse arthritis has not been found, and on the basis of risk-benefit analyses, glucosamine sulphate remains a recommended basic therapy.

Glucosamine can reduce the side effects of pain killers

In addition to this, it has been demonstrated that a glucosamine protects against stomach damage, which occurs when the painkiller indomethacin is prescribed. Similarly, the use of multi-nutrient combination therapy has shown a considerable reduction in the symptoms of arthritis in mice.

The authors finally highlight that the combination of painkillers and glucosamine could offer a way of saving on painkillers for patients with arthritis in the future. This provides a way of reducing the possible side effects of the medication in the gastrointestinal tract.

Glucosamine in osteoarthritis in horses

An interesting question asked was whether glucosamine, when taken orally, arrives in the cartilage of joints at all? To determine this a few studies were conducted with animals, which had been given glucosamine sulphate or glucosamine hydrochloride.

Subsequently the blood and synovial fluid of the animals was tested in order to determine the concentration of glucosamine. In this way, Meulyzer and colleagues investigated the levels of the nutrient in horses, which were given 20mg glucosamine per kilogram of body weight orally or intravenously (equivalent to a human dose of 1500 mg in a person weighing 75kg)⁷.

After 5 to 720 minutes blood samples were taken from the animals at regular intervals. A sample of synovial fluid was taken 48 hours before the experiment, in addition to being taken 1, 6 and 12 hours after glucosamine was consumed.

In the case of oral administration of glucosamine, the concentration of glucosamine rose to 1 µg/ml. The concentration in the synovia was significantly higher after 1 and 6 hours than the initial value.

Additionally, glucosamine sulphate had a significantly higher level of bioavailability than glucosamine hydrochloride. However the authors could not comment upon the effect of glucosamine on the joint cartilage. In other studies which involve the use of human test subjects, more questions could be answered

Glucosamine can reduce the need for painkillers

In their study, scientists in South Korea have reported the possibility of using glucosamine hydrochloride to reduce the prescription of painkillers for patients dependent upon their individual circumstances ⁸.

The researchers wanted to clarify whether glucosamine could help reduce dosage of painkillers in the case of arthritis. A mouse model was used for this purpose. The animals received indomethacin as a painkiller, or a combination of indomethacin and glucosamine hydrochloride. Less inflammatory mediators were formed when mice were given the combination with glucosamine hydrochloride. Furthermore, painkillers could be significantly reduced.