One Cycle of Steroids Won't Hurt - True or False?
Updated: Sep 30
“Steroid use” has long been present within bodybuilding and professional fitness communities. However, in recent years it has gained popularity even among younger beginners, largely due to social media, fitness influencers, and unrealistic portrayals of the “ideal muscular body.”
When we talk about “steroid use,” the term can refer to several different things. Steroids are a class of organic compounds with a four-carbon ring structure, involved in numerous biological processes such as hormone production, inflammation control, and metabolic regulation. This means steroid use could cover topics as different as corticosteroids (used as immunosuppressants or for medical treatment), testosterone replacement therapy (TRT) for hormone deficiencies, and anabolic-androgenic steroids (AAS) used to enhance muscle mass.
In this article, however, we will focus specifically on anabolic-androgenic steroids (AAS), which are commonly misused in bodybuilding and fitness to accelerate muscle growth.
Anabolic-Androgenic Steroids (AAS)
Anabolic-androgenic steroids are natural or synthetic hormones based on testosterone. Because of their ability to significantly increase muscle mass and strength when taken in high doses, they are prone to misuse.
Anabolic effects: promote muscle growth and development.
Androgenic effects: support and maintain male characteristics such as facial hair, voice deepening, and testicular development.
Testosterone itself is the primary anabolic-androgenic steroid produced naturally in the human body.
AAS are typically administered through intramuscular injections or taken orally. Once in the bloodstream, they reach target tissues and enter cells by passive diffusion across the cell membrane. Inside the cell, AAS can bind to androgen receptors and move into the nucleus to stimulate protein synthesis. However, they can also be converted into estrogen or dihydrotestosterone (DHT) before reaching the nucleus, potentially leading to gynecomastia, acne, and hair loss.
Mechanism of Action
AAS bind to androgen receptors and enhance the activation of genes involved in protein synthesis, muscle fiber growth, and cellular adaptation. They:
Suppress myostatin, a protein that limits muscle growth.
Activate Akt/mTOR pathways to increase protein synthesis.
Stimulate IGF-1 production, promoting cell proliferation and differentiation.
Influence Notch signaling, which aids in muscle fiber repair and regeneration 【Baig et al., 2022】.
Effects on Body Composition
AAS increase muscle mass by:
Boosting protein synthesis.
Reducing protein breakdown mediated by glucocorticoids.
For example, one study found that 600 mg testosterone injections led to greater lean mass gains in non-training individuals compared to those who trained but did not receive injections.
Most studies on different types of AAS report gains of 2–5 kg of muscle mass within 10 weeks of use. Long-term use (up to two years) has been associated with gains as high as 12.7 kg.
Regional muscle growth (neck, chest, shoulders, and arms) has also been consistently observed. However, maintaining these changes after discontinuation is difficult, as it requires extreme training and nutrition. Still, partial effects can remain for up to three months after stopping.
Effects on Strength
Beyond muscle size, AAS use is also strongly linked to strength gains. Initially, it was believed that only trained athletes would see this benefit. However, research shows that even beginners can experience significant increases in 1-rep max performance when using steroids.
Results vary depending on the type and dose of steroid. For instance, metandienone (methandrostenolone) has been widely studied: most studies confirm strength increases, though a few found no effect. Generally, doses above 10 mg per day are associated with strength gains.
Side Effects of AAS Use
Surveys reveal that the majority of AAS users report unwanted side effects during and after use.
Common Side Effects
Increased libido or reduced libido (depends on hormonal balance).
Acne and hair growth.
Aggressive behavior.
Systemic problems: high blood pressure, appetite changes, psychological effects, hair loss, gynecomastia.
Initially, external testosterone can raise libido, but long-term use suppresses natural testosterone production and disrupts estrogen balance, often leading to reduced sexual desire.
Liver
AAS are metabolized by the liver, so toxicity depends on frequency, dosage, and method of use. Reported effects include:
Elevated liver enzymes.
Cholestatic syndrome (impaired bile flow).
Peliosis hepatis (blood-filled cysts).
Benign or malignant tumors.
Fatty liver disease.
Lipids
AAS use increases hepatic lipase activity, reducing HDL (“good” cholesterol) and raising LDL and triglycerides, thereby increasing cardiovascular risk. Even low doses have been shown to lower HDL by ~20%.
Cardiovascular Risks
AAS are associated with:
Cardiomyopathy (enlarged heart chambers, impaired pumping).
Heart attacks and arrhythmias, sometimes leading to sudden death.
Thrombosis (blood clots) and blocked vessels.
Kidneys
Direct effects include acute kidney injury or chronic kidney failure. Indirect effects arise from hypertension and cardiovascular complications.
Sexual Function
AAS suppress natural testosterone production and the hypothalamic-pituitary axis, leading to:
Erectile dysfunction.
Reduced libido.
Testicular shrinkage.
Infertility.
Short-term users (<1 year) may see testosterone return to normal without intervention after stopping. Long-term users often require post-cycle therapy (PCT) to restore function.
Psychological Effects
AAS can alter brain chemistry and behavior:
Mimic addictive drugs by affecting dopamine pathways.
Increase aggression.
Long-term use linked to prefrontal cortex thinning and emotional regulation disorders.
“One Cycle Won’t Hurt” – True or False?
The claim that a single steroid cycle is harmless ignores how quickly anabolic-androgenic steroids (AAS) disturb the body’s physiology. Even short-term exposure initiates changes that can persist long after discontinuation.
1. Endocrine Suppression Happens Immediately
Exogenous testosterone suppresses the hypothalamic-pituitary-gonadal (HPG) axis within days. Natural testosterone production is reduced, sperm development slows, and testicular volume decreases. While some men regain baseline levels, others never fully recover, leaving them with chronically low testosterone or fertility issues after only one cycle.
2. Early Cardiovascular Remodeling
Studies show lipid imbalances (↓HDL, ↑LDL and triglycerides) appear in the first weeks of steroid use. This accelerates arterial plaque formation and endothelial dysfunction — processes that do not simply “reset” after stopping. Even if blood values normalize, vascular damage and increased long-term cardiovascular risk may remain.
3. Irreversible Tissue Changes Can Start Quickly
Short-term steroid use can trigger androgen-to-estrogen conversion, leading to gynecomastia, or conversion to DHT, accelerating male-pattern hair loss in predisposed individuals. Both conditions can appear in the first cycle and may be permanent.
4. Neurochemical Alterations
Steroids act on dopamine and serotonin pathways, similar to addictive substances. Even brief exposure can sensitize these systems, increasing the risk of dependency and long-term mood instability.
5. The Illusion of “Safe Gains”
Although muscle and strength gains appear rapidly, they rely on suppressed natural physiology. Once the cycle ends, the body faces a rebound phase of low testosterone, high estrogen, and unstable cortisol. This post-cycle state often brings fatigue, depression, and muscle loss, making the user more likely to repeat cycles — creating the very dependence they hoped to avoid.
Conclusion
Anabolic-androgenic steroids (AAS) are clinically proven to increase muscle mass and strength. However, whether used short-term or long-term, they carry serious health risks across multiple organ systems. Use should only ever occur under strict medical supervision — and recreational, unsupervised use carries significant dangers.
References
Bond P, Smit DL, de Ronde W. Anabolic-androgenic steroids: How do they work and what are the risks? Front Endocrinol (Lausanne). 2022 Dec 19;13:1059473. doi: 10.3389/fendo.2022.1059473. PMID: 36644692; PMCID: PMC9837614.
Wenbo Z, Yan Z. The Uses of Anabolic Androgenic Steroids Among Athletes; Its Positive and Negative Aspects – A Literature Review. J Multidiscip Healthc. 2023 Dec 29;16:4293-4305. doi: 10.2147/JMDH.S439384. PMID: 38170017; PMCID: PMC10759908.
Baig MH, Ahmad K, Moon JS, Park SY, Ho Lim J, Chun HJ, Qadri AF, Hwang YC, Jan AT, Ahmad SS, Ali S, Shaikh S, Lee EJ, Choi I. Myostatin and its Regulation: A Comprehensive Review of Myostatin Inhibiting Strategies. Front Physiol. 2022 Jun 23;13:876078. doi: 10.3389/fphys.2022.876078. PMID: 35812316; PMCID: PMC9259834.
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