The term “muscle enhancer” covers a wide array of substances used to increase muscle mass, strength, and athletic performance. This category ranges from common dietary supplements to highly regulated drugs, all sought after for their ability to accelerate muscle repair and growth. These compounds have significant differences in their legal status, biological actions, and potential health consequences.
Regulated and Prohibited Substances
Anabolic-Androgenic Steroids (AAS) are synthetic variations of the male sex hormone, testosterone. These substances are tightly controlled due to their potency and adverse effects. In the United States, they are Schedule III controlled substances, making possession without a valid prescription illegal. While prescribed for conditions like delayed puberty or muscle wasting, illicit use often involves much higher doses.
Selective Androgen Receptor Modulators (SARMs) are investigational drugs designed to target androgen receptors in specific tissues like muscle and bone. This targeted action is intended to produce muscle-building effects with fewer side effects than steroids. However, no SARMs are approved for human consumption and are illegally marketed as “research chemicals” online, posing risks due to a lack of regulation and safety data.
Prohormones are precursors to anabolic hormones, converted into hormones like testosterone within the body. Once sold as dietary supplements, legislative changes reclassified many prohormones as controlled substances. This made them illegal to sell and possess, as they can produce similar muscle-building effects and health risks as traditional anabolic steroids.
Widely Available Performance Supplements
In contrast to regulated drugs, several performance supplements are legally and widely available. Creatine is one of the most studied supplements, known for its role in cellular energy production. It increases the body’s stores of phosphocreatine, which helps regenerate adenosine triphosphate (ATP), the cell’s primary energy source. This allows for improved performance in short, intense efforts, translating to greater strength and muscle gains over time.
Protein powders offer a convenient way to increase daily protein intake. Protein is necessary for repairing the muscle damage that occurs during resistance training, a process that leads to muscle growth. Whey and casein, derived from milk, are popular choices, alongside plant-based options like soy or pea protein, providing the components for muscle recovery.
Beta-alanine is an amino acid that helps buffer acidity in muscles during intense exercise. As hydrogen ions accumulate, they cause a drop in pH and muscular fatigue. By increasing carnosine concentrations, beta-alanine delays fatigue, allowing athletes to increase their total training volume, which stimulates muscle growth.
The Role of Hormones and Precursors
The body’s natural capacity for muscle growth is governed by hormones, with testosterone being a primary regulator of this process. Endogenous testosterone promotes muscle growth by binding to androgen receptors located on the surface of muscle cells. This binding event initiates a cascade of signals within the cell that increases the rate of muscle protein synthesis. This process tips the balance toward an anabolic, or tissue-building, state, which is the fundamental pathway for muscle hypertrophy.
Health Implications and Side Effects
The use of regulated and prohibited substances carries well-documented health risks. Anabolic steroids place considerable strain on the cardiovascular system and can damage the liver, especially oral formulations. Long-term use also disrupts the body’s natural hormone production, leading to issues such as:
- High blood pressure
- Problematic changes in cholesterol levels
- An increased risk of heart attack and stroke
- Potential infertility in men
- Testicular atrophy in men
Conversely, side effects from widely available supplements are considered mild for most healthy individuals. Creatine can cause water retention, leading to a slight increase in body weight, and some users may experience digestive upset. These effects are temporary and often resolve on their own, but individuals with pre-existing kidney conditions should consult a healthcare provider before use.
The health implications of SARMs are less understood due to a lack of long-term clinical trials in humans. Because they are often sourced from unregulated manufacturers, there is a risk of contamination with other harmful substances. The potential for side effects similar to those of traditional steroids, including hormone suppression and liver toxicity, remains a concern for medical professionals.