Sustanon 250 and the bone-and-joint system

When people talk about testosterone and the musculoskeletal system, they usually mention only muscles. But androgens and their metabolite estradiol affect bones, tendons and joint cartilage too. Some of these effects are beneficial, others create specific injury risks. The editorial team broke down what is known about the effect of Sustanon 250 on the bone-and-joint system.

Testosterone, estradiol and bone tissue

Bone is a living tissue that is constantly renewed: osteoclasts break down the old matrix, osteoblasts build a new one. The balance between these processes determines the mineral density and strength of the skeleton. Sex hormones are among the main regulators of this balance in both sexes.

In men, testosterone affects bone in two ways. The first is directly through androgen receptors, which stimulates periosteal growth, that is, an increase in bone diameter. That is why men’s bones are on average larger and stronger than women’s.

The second way is through estradiol, which is formed from testosterone under the action of aromatase. It turned out that it is estrogen that is the key brake on bone breakdown in men too. Men with rare mutations of aromatase or the estrogen receptor have low bone density and unclosed growth zones, despite normal or high testosterone.

The study by Finkelstein and colleagues (2013) in the New England Journal of Medicine demonstrated this experimentally: when men had their own hormones suppressed and were given testosterone together with an aromatase inhibitor, markers of bone breakdown increased. That is, for bones not only testosterone is important, but also a sufficient level of its estrogenic metabolite.

Bone mineral density: study data

For people with testosterone deficiency, replacement therapy has a proven positive effect on bones. In a study from the TTrials program (Snyder et al., 2017), older men with low testosterone received testosterone gel for a year, and their volumetric mineral density and estimated bone strength increased compared with placebo, especially in the spine.

The instructions for Sustanon 250 mention, among the indications for replacement therapy, in particular the prevention of osteoporosis associated with hypogonadism. However, in this case it is about returning the hormone to normal in people who had a deficiency.

For healthy men with normal testosterone levels, supraphysiological doses do not provide a proportional “strengthening” of bones. Moreover, with non-medical use, aromatase inhibitors are often used to reduce estrogenic side effects. As studies show, this can reduce the protective effect of estradiol on bone.

The period most sensitive to hormonal fluctuations is after stopping the use of androgens. Suppression of one’s own testosterone production can last for months, and during this time the bone is in a state of hormonal deficiency. For a one-time episode the consequences are usually insignificant, but repeated cycles with prolonged “dips” are theoretically unfavorable.

Tendons: the risk of ruptures

The most discussed problem of the musculoskeletal system with androgen use is tendon ruptures. Many clinical cases of ruptures of the biceps tendon of the arm, the pectoralis major muscle and the quadriceps muscle of the thigh in athletes who used steroids are known.

More systematic data were provided by the study by Kanayama and colleagues (2015) in the American Journal of Sports Medicine. Comparing experienced weightlifters who used anabolic steroids with those who did not, the authors found a significantly higher frequency of tendon ruptures in the first group, especially of the tendons of the upper body.

The main explanation is a mismatch in adaptation rates. Androgens quickly increase muscle strength, while tendons, which have a slower collagen metabolism, do not have time to adapt to the new loads. As a result, during maximal effort it is precisely the tendon that becomes the weak link.

Experimental studies in animals also point to possible changes in collagen structure and a decrease in tendon elasticity under the action of high doses of androgens, although transferring these data to humans requires caution.

A tendon rupture is a serious injury that often requires surgical treatment and long rehabilitation, and sometimes leaves a permanent reduction in strength or function. For an athlete this can mean the end of a career.

Joints, growth zones and myths

In the sports community there is a widespread belief that some steroids “lubricate the joints.” Usually it is associated with nandrolone, which is not part of Sustanon 250. There is no evidence that testosterone or its esters treat or protect joint cartilage in healthy people.

A subjective reduction in joint pain on androgens is partly explained by fluid retention, an anti-inflammatory effect and a change in pain perception. However, the feeling of comfort may mask overload, which increases the risk of injury.

A separate topic is adolescents. During the growth period, androgens through estradiol accelerate the closure of the epiphyseal growth zones. Using testosterone in adolescence without medical indications can lead to a premature end of growth and a reduction in final height. That is why such drugs in pediatrics are used exclusively under the supervision of an endocrinologist.

Another common myth is that “stronger muscles protect the joints.” This is partly true, but only when strength increases gradually along with the adaptation of ligaments and tendons. A sharp increase in strength without corresponding preparation of the connective tissue gives the opposite effect.

Prevention and examination

For people who have hypogonadism and receive testosterone as prescribed by a doctor, assessment of bone condition is a standard part of the examination. To determine mineral density, densitometry (DXA) is used, especially in the case of prolonged hormone deficiency or a history of fractures.

The general principles of protecting the musculoskeletal system are relevant for everyone who trains:

• a gradual increase in loads, especially in pressing and pulling exercises with maximum weight;
• a full warm-up and control of technique;
• sufficient intake of calcium, vitamin D and protein;
• attention to pain in the area of tendon attachment — this is a signal of overload, not “normal” fatigue;
• timely visits to a sports doctor or orthopedist for injuries.

Pain in the tendon area, a feeling of “clicking” or sudden weakness during an exercise are reasons to immediately stop the load. If a rupture is suspected, time matters: some tendon repair operations are more effective if performed in the first weeks after the injury.

It is important to openly inform the doctor about the use of androgens: this affects the assessment of injury risk, the healing prognosis, and the rehabilitation plan.

Editorial conclusions

Testosterone and its metabolite estradiol are important for bone health. With a hormone deficiency, replacement therapy improves mineral density, but supraphysiological doses do not provide healthy people with a proportional “strengthening” of the skeleton.

The greatest practical risk for the musculoskeletal system is tendon ruptures due to a mismatch in the rates of strength growth and connective tissue adaptation. For adolescents, an additional risk is premature closure of growth zones.

The notion of “lubricating the joints” has no evidence base, and a reduction in pain may conceal overload.

We also recommend reading our articles about the body’s recovery after using Sustanon 250, about its metabolites and conversion to estradiol, and about the drug’s legal status.

References

1. Finkelstein JS, Lee H, Burnett-Bowie SA, et al. Gonadal steroids and body composition, strength, and sexual function in men. N Engl J Med. 2013;369(11):1011–1022.
2. Snyder PJ, Kopperdahl DL, Stephens-Shields AJ, et al. Effect of testosterone treatment on volumetric bone density and strength in older men with low testosterone: a controlled clinical trial. JAMA Intern Med. 2017;177(4):471–479.
3. Kanayama G, DeLuca J, Meehan WP 3rd, et al. Ruptured tendons in anabolic-androgenic steroid users: a cross-sectional cohort study. Am J Sports Med. 2015;43(11):2638–2644.
4. Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–375.
5. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.
6. Sustanon 250 mg/ml solution for injection. Summary of Product Characteristics (SmPC).