Steroids and Protein Synthesis

Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.


In this article, we'll briefly review the relationship between steroids and protein synthesis.

The main principle behind the connection is that a hormone (or steroid) called testosterone binds to the androgen receptor in the cytoplasm and causes gene transcription, which directs protein synthesis.

Anabolic steroids mimic the effects of male sex hormones

While athletes have traditionally used anabolic steroids for strength and performance, the use of these drugs has been restricted in many countries.

In 1976, the International Olympic Committee banned anabolic steroids and the World Anti-Doping Agency added them to its list of banned substances.

However, abuse of these drugs continues to grow in the general public and in fitness and athletic centers, mostly for aesthetic purposes. As a result, the misuse of anabolic steroids has been labeled a public health concern.

Anabolic steroids, also called anabolic-androgenic steroids (AAS), are powerful drugs with numerous adverse effects.

They are often abused by athletes and adolescents and can cause a variety of cardiovascular and liver problems. Their anabolic effects increase protein synthesis and increase muscle and bone mass.

Anabolic steroids can be injected, taken orally, or applied externally in the form of creams and gels.

Their abuse can lead to severe side effects and are classified as Schedule III Controlled Substances in the U.S. because abusers may abuse them at up to 100 times the dosage prescribed for medical conditions. 

Anabolic steroids mimic the effects of male hormones on protein synthesis and can be used by athletes to increase their strength and muscle mass.

However, they should not be used for an extended period of time due to their risks of causing severe side effects. In extreme cases, testosterone replacement therapy may be necessary.

AAS abuse can lead to psychological problems including depression and anxiety. It is essential for healthcare providers to educate patients about the consequences of prolonged AAS abuse and the effects on their cardiovascular health.

AAS abuse can also lead to changes in central nervous system function, which can affect hormone levels and negatively impact a person's mood. It can also affect their exercise motivation.

AAS mimic the effects of testosterone by altering gene expression by binding to the androgen receptor in the cytoplasm.

This, in turn, interferes with testosterone biosynthesis by inhibiting the conversion of cholesterol to progesterone to androstenedione through CYP17A1.

Additionally, AAS interferes with the conversion of cholesterol to testosterone through the CYP11A1 enzyme. It also lowers the production of endogenous testosterone.

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They can increase muscle strength

In the case of steroids, they can increase protein synthesis by inhibiting protein breakdown in the muscle cells.

Despite the potential risks, anabolic steroids have been found to increase the strength and mass of a person's muscles. In the 2008 Beijing Olympics, 22 of 37 athletes were disqualified for using anabolic steroids.

Protein synthesis is an essential part of bodybuilding or even to prevent muscular dystrophy among surgery patients or those recoverying from diseases. Proteins synthesized by muscles are called amino acids.

A high synthesis rate means more protein can be made in the same amount of time. Protein synthesis is measured in %/h.

For example, a fractional synthetic rate of 0.04 %/h indicates that about 0.04% of total muscle protein is synthesized per hour. That's equivalent to building a new muscle every three months.

They can increase protein synthesis

Steroids increase protein synthesis in the body by encouraging the production of amino acids.

This process helps the body create muscle tissue. It also increases metabolism, enabling a person to burn more calories per day. If used in conjunction with an exercise regimen, steroids can also improve recovery time.

When recovery times are reduced it means the person can train for longer periods and at a higher frequncy. More training and better recovery means more muscle development.

These steroids are commonly used by athletes who compete in sports requiring explosive movements. For example, a sprinter might use anabolic steroids to boost his explosiveness out of the blocks during a race.

Steroids may also have an indirect impact on the central nervous system (CNS), which is responsible for increased aggression and competitiveness. 

However, there are still adverse effects associated with anabolic steroids. Some of these drugs can decrease the effectiveness of the reproductive system and affect the cardiovascular system.

Some steroids may cause increased protein synthesis but may also lead to liver problems, particularly those steroids which are taken orally. The effects of anabolic steroids may last for long after discontinuing use.


Testosterone administration improves lean body mass and increases muscle protein synthesis.

In addition, testosterone administration improves the transport and reutilization of amino acids. It also increases the ratio of protein breakdown to protein synthesis.

Although this is an important benefit, there are some risks associated with testosterone use.

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