Glucosamine and Chondroitin During a Bulk: Is There a Point

A mass-gaining phase is associated with heavy working weights, frequent compound exercises and an increase in one's own body weight. The logical question: shouldn't the joints be "insured" with glucosamine and chondroitin? The editors assessed how well this idea aligns with study data and where the real risks to the joints lie during a bulking phase.

What happens to the joints during a bulk

A bulking phase usually means a progression of working weights in compound movements: squats, presses, deadlifts. The load on the knee, hip and shoulder joints increases not only because of the barbell weight but also because of the growth in the athlete's body mass. For cartilage, which has no blood supply of its own and is nourished by diffusion from the synovial fluid, moderate cyclic loading is beneficial, whereas excessive and monotonous loading is not.

Tendons and ligaments adapt to strength training more slowly than muscles. Muscle strength can increase within a few weeks, whereas the remodeling of collagen structures takes months. Because of this gap in pace, an athlete on a bulk sometimes "outruns" their own connective tissue: the muscles are already ready for more weight, but the tendons are not yet.

Typical complaints during this period are elbow pain from close-grip bench presses and curls, discomfort in the front of the shoulder, pain under the kneecap after deep squats. These are mostly overload tendinopathies, not cartilage problems, so chondroprotectors here aim at the wrong target.

Also, on a bulk people more often train with fewer repetitions and closer to failure. This is effective for strength but requires impeccable technique and thoughtful planning, otherwise the risk of microtrauma accumulates.

Do the supplements affect muscle growth

Neither glucosamine nor chondroitin is an anabolic substance. They do not stimulate muscle protein synthesis, do not affect hormone levels and do not increase strength. In the IOC consensus on dietary supplements for athletes (Maughan et al., 2018) they are not among the agents with a proven effect on performance.

Sometimes sellers argue like this: "healthy joints - more training - more muscle." The logic is formally correct, but it works only if the supplement actually preserves the joints, and there is no direct evidence of this for healthy athletes who train with weights.

By comparison, within a bulk a clear evidence base belongs to entirely different things: sufficient protein, a calorie surplus, progressive loading, creatine monohydrate. A meta-analysis by Morton and colleagues (2018) showed that additional protein enhances the gain in lean mass against a background of strength training - that is where the real "lever" lies.

So, if we consider supplements from the standpoint of their effect on bulking results, glucosamine and chondroitin end up at the very bottom of the priority list.

What is known about cartilage protection

The only field where glucosamine and chondroitin have been studied thoroughly is osteoarthritis. The GAIT study (Clegg et al., 2006) found no overall advantage over placebo for knee pain, and the network meta-analysis by Wandel and colleagues (2010) concluded there was no clinically meaningful effect.

On the other hand, the MOVES study (Hochberg et al., 2016) showed that the combination of pharmaceutical chondroitin sulfate and glucosamine hydrochloride was not inferior to celecoxib in its effect on knee osteoarthritis pain after six months. Authors assessing data quality stress that the results depend heavily on the specific product.

None of these studies examined young strength athletes without joint disease, so extending the conclusions to "prevention" during a bulk is extrapolation. Healthy cartilage gets everything it needs from the diet and does not require "building material" in the form of capsules.

Where older athletes with already existing joint changes are concerned, the conversation is different. For them, the decision to take chondroprotectors should be made by a doctor, taking into account the diagnosis and guidelines.

Costs and priorities: where the bulking budget goes

A bulk is an expensive period: the amount of food increases, and people often buy protein, gainer, creatine. Quality glucosamine and chondroitin products with verified active-substance content are also not cheap, and to assess their effect they must be taken for months.

Given the evidence base, the editors consider it reasonable to allocate resources by priority. First, a diet with sufficient protein and energy, then proven supplements, and only when there are specific indications, agents for the joints.

1. Meet the protein requirement, roughly 1.6 g per kilogram of body weight per day and above according to ISSN recommendations (Jäger et al., 2017).
2. Ensure a moderate calorie surplus without excessive fat gain.
3. Consider creatine monohydrate as the supplement with the best evidence base for strength.
4. Joint agents - only when there is a diagnosis or a doctor's recommendation.

This approach does not mean that chondroprotectors are "harmful." They are generally well tolerated; among side effects, mild gastrointestinal discomfort is most commonly described. But safety does not equal efficacy.

Separately, it is worth mentioning people who get subjective relief from such supplements. The placebo effect in joint pain is well documented in osteoarthritis studies, and it is quite real for how one feels, but it does not indicate cartilage protection.

Practical recommendations for joints during a bulk

The most effective joint protection during a bulk is sensible programming. The progression of weights should be gradual, and the volume of heavy sets controlled. Periodization with lighter and heavier weeks gives connective tissue time to adapt.

A warm-up before heavy sets is not a formality. A few warm-up sets with a gradual increase in weight raise tissue temperature and prepare the joints for the load.

• Alternate exercise variations: different grip, bench angle, type of bar - this distributes the load.
• Do not neglect full-range-of-motion exercises, but with a controlled weight.
• Watch your body weight gain: excessive fat gain adds load on the knees without benefit to the muscles.
• If pain does not go away within 2-3 weeks, see a sports physician.

Sleep and nutrition also work in favor of the joints. The restoration of collagen structures happens mostly during rest, and chronic sleep deprivation negates part of the benefits of even an ideal program.

If an athlete has diagnosed osteoarthritis or an old joint injury, the choice of product should be made with a doctor, giving preference to pharmaceutical forms with standardized content.

Editorial conclusions

Glucosamine and chondroitin do not speed up muscle mass gain and have no proven preventive effect for healthy joints in strength athletes.

The most common problems during a bulk are tendon overload from rapid weight progression, and they are solved by training planning, not by chondroprotectors.

For people with osteoarthritis the evidence picture is mixed, so intake should be discussed with a doctor and, where possible, based on pharmaceutical products.

We also recommend reading our articles on glucosamine and chondroitin during a cut, on the side effects of these supplements and on how to correctly choose the dosage form.

References

1. Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006;354(8):795–808.
2. Wandel S, Jüni P, Tendal B, et al. Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis. BMJ. 2010;341:c4675.
3. Hochberg MC, Martel-Pelletier J, Monfort J, et al. Combined chondroitin sulfate and glucosamine for painful knee osteoarthritis: a multicentre, randomised, double-blind, non-inferiority trial versus celecoxib. Ann Rheum Dis. 2016;75(1):37–44.
4. Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.
5. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
6. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
7. Bannuru RR, Osani MC, Vaysbrot EE, et al. OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage. 2019;27(11):1578–1589.