Boldenone undecylenate and the musculoskeletal system
In athletic circles, boldenone is credited with the ability to "lubricate the joints" and strengthen ligaments. At the same time, orthopedists regularly see tendon ruptures in young athletes who use anabolic steroids. The editorial team looked into what science says about the effect of androgens on bones, tendons and joints and how well-founded the popular notions are.
Androgens, estrogens and bone tissue
Bone is living tissue that is constantly renewed: osteoclasts destroy the old matrix, osteoblasts build a new one. Sex hormones regulate this balance. In men, androgens contribute to increasing the size and thickness of the cortical layer of bones, while estrogens, formed from testosterone, are critically important for preserving mineral density.
The role of estrogens in men was clearly shown by the work of Finkelstein and colleagues (2013) in the New England Journal of Medicine. When the production of sex hormones was pharmacologically suppressed in men and testosterone was administered with or without aromatase blockade, it was specifically the estrogen deficiency that was associated with increased bone resorption.
Boldenone aromatizes to a lesser degree than testosterone. For bones this has a twofold meaning: on the one hand, boldenone as an androgen acts on bone cells; on the other, if it suppresses one's own testosterone and at the same time provides less estrogen, the total estrogenic effect may decrease. There are no quantitative data in humans.
Especially risky, from the point of view of bones, is an artificial sharp reduction of estrogens, for example by self-administration of aromatase inhibitors. Low estradiol in men is associated with reduced bone density, joint pain and a worsening of the lipid profile.
Tendons: muscle strength versus collagen strength
The most documented orthopedic risk of anabolic steroids is tendon ruptures. In a cross-sectional cohort study by Kanayama and colleagues (2015) in the American Journal of Sports Medicine, tendon ruptures occurred more often among weightlifters who used anabolic steroids than among those who did not. This especially concerned the tendons of the upper limbs: the biceps, triceps, pectoral muscle.
The mechanism is explained by an imbalance of adaptation. Under the action of androgens, muscles grow and gain strength within weeks, while tendons, which consist mainly of collagen and have a slow turnover, adapt over months and years. The load increases faster than the strength of the "attachment."
Experimental animal studies also indicate that high doses of androgens can change the structure of collagen fibers, making tendons stiffer and less able to absorb energy. However, these data are contradictory and do not fully transfer to humans.
An additional factor is behavioral: the feeling of strength and quick recovery pushes one to work with maximal weights without sufficient adaptation. It is precisely at the moment of maximal effort, for example in the bench press, that a rupture often occurs.
The myth of "joint lubrication"
One of the most persistent legends around boldenone is the idea that it "moisturizes the joints" or improves the condition of the cartilage. The mechanism is usually explained by fluid retention or an effect on collagen synthesis. There are no clinical studies that would confirm an improvement in the condition of the joints in humans specifically under the action of boldenone.
A subjective reduction of joint pain against the background of steroids can be explained by other factors: the anti-inflammatory effect of some hormonal changes, an increase in the pain threshold, an improvement in mood and a feeling of energy. However, a reduction in pain does not mean tissue restoration and can mask an injury.
Articular cartilage has almost no blood vessels and recovers very slowly. Excessive loads, which become possible thanks to an increase in strength, can accelerate its wear. This especially concerns the knee, shoulder and elbow joints in strength sports.
On the contrary, joint pain is often associated with a sharp reduction of estrogens, for example after discontinuing drugs or against the background of self-administration of aromatase inhibitors. This effect is described in women who receive aromatase inhibitors for breast cancer and is a separate argument against self-treatment.
| Notion | What is known scientifically |
|---|---|
| Boldenone "lubricates the joints" | There are no studies that confirm it |
| Steroids strengthen tendons | Data indicate an increased risk of ruptures |
| Androgens are useful for bones | In physiological doses yes; estrogens play a significant role |
| Less pain means a healthier joint | Pain relief can mask damage |
Adolescents and growth plates
In adolescents, the length of bones increases due to the growth plates (epiphyseal cartilages). At the end of puberty, under the action of estrogens, these plates close, and growth in length stops. This also applies to boys: in men with mutations that impair the action of estrogens, the growth zones remain open.
Supraphysiological doses of androgens, part of which is converted into estrogens, can prematurely close the growth zones. The result is a lower final height than could have been. This effect is irreversible.
That is exactly why in medicine androgens are prescribed to adolescents only for clear indications, for example in delayed puberty, and with monitoring of bone age by an X-ray of the hand.
In addition to height, in adolescence peak bone mass is formed, which determines the risk of osteoporosis in the future. Any hormonal interventions during this period can have consequences decades later.
- Premature closure of the growth zones is irreversible.
- An effect on the formation of peak bone mass.
- An increased risk of tendon injuries against the background of an immature musculoskeletal system.
Signs of problems and examination
An alarming signal is pain at the site of tendon attachment that intensifies with load, especially in the area of the elbow, shoulder, knee or Achilles tendon. Chronic tendinopathy often precedes a rupture, so it should not be ignored.
An acute rupture is usually accompanied by a feeling of a "click," sharp pain, swelling and a change in the contour of the muscle, for example a "bunching up" of the biceps. Complete ruptures often require surgical treatment in the first weeks, so it is important not to postpone seeing an orthopedist.
To assess bones, densitometry (DXA) is used; for tendons and joints, ultrasound and MRI. A hormonal examination with determination of testosterone, estradiol, LH and FSH helps to understand whether the problems are related to a hormonal imbalance.
When seeing a doctor, it is important to report the use of steroids. This affects the choice of tactics, the assessment of the risk of repeat injuries and the prognosis after surgery.
Editorial conclusions
The popular idea of boldenone "lubricating the joints" has no scientific confirmation; a reduction in pain can mask damage.
The most documented risk is tendon ruptures due to the discrepancy between the rapid growth of muscle strength and the slow adaptation of collagen structures.
For bones, not only androgens but also estrogens are important; in adolescents, supraphysiological doses threaten irreversible premature closure of the growth zones.
We also recommend reading our materials on the estrogenic activity of boldenone, on a complete overview of the side effects of boldenone and on the myths about boldenone.
References
- 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.
- 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.
- Smith EP, Boyd J, Frank GR, et al. Estrogen resistance caused by a mutation in the estrogen-receptor gene in a man. N Engl J Med. 1994;331(16):1056–1061.
- 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.
- 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.
- Nieschlag E, Behre HM, Nieschlag S (eds). Testosterone: Action, Deficiency, Substitution. 4th ed. Cambridge University Press; 2012.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
