Sex-hormone binding globulin binds to over half of testosterone molecules within a male’s plasma and renders them inactive

Elderly individuals (over the age of 65) tend to exhibit altered concentrations of plasma proteins such as albumin and sex-hormone binding globulin (SHBG) compared to younger adults

Two individuals could simultaneously administer an intramuscular injection of testosterone cypionate, yet one individual will likely eliminate it sooner from his system than the other. Though the elimination times may differ significantly, they will likely differ based on a variety of interindividual factors. These factors include things like a person’s age, body mass, plasma proteins, and renal function.

Age: An individual’s age likely plays a role in how long exogenously administered testosterone stays in their system. As a result, it would be expected that the pharmacokinetics of testosterone would be altered among those considered elderly to younger adults.

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Body mass: A person’s body mass is often influenced by the amount of testosterone circulating throughout the body. Individuals with higher testosterone have greater propensity to build muscle and burn fat stores. Additionally, body mass index (BMI) may also affect how long testosterone esters remain in a user’s system after discontinuation. That said, it is unclear exactly how BMI or body fat percentage may affect the half-life of a specific testosterone ester.

Dietary intake: It is understood that a testosterone user’s age can affect sex-hormone binding globulin (SHBG) levels, which in turn can influence how long testosterone stays in their system. In addition to age, dietary intake can also influence whether an individual exhibits high or low SHBG concentrations. The more protein you consume, the lower your SHBG levels are likely to be, whereas the more fiber you consume, the greater your SHBG concentrations are likely to be.

The greater your levels of SHBG, the less free testosterone you’re likely to have circulating throughout your system. The lower your SHBG levels, the greater your concentration of free testosterone is likely to be. Therefore it could be surmised that eating a high-fiber diet may result in faster elimination of testosterone esters than a diet high in protein. On a side note, you may be interested to read about “Foods That Increase Testosterone Levels” via boosting endogenous production.

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Hepatic function: Individuals with compromised hepatic function may metabolize testosterone at a slower rate, ultimately retaining it for a longer duration than those with normative liver health. Within the liver, testosterone is metabolized by hepatic mixed function oxidases to convert testosterone to androstenedione (via oxidation of the 17-OH group). It is possible that 17-OH oxidation is poorer as a result of hepatic impairment, leading to a longer term of testosterone elimination.

Metabolic rate: It may be necessary to consider your BMR (basal metabolic rate) when contemplating how long testosterone is likely to stay in your system. Though testosterone can speed up your BMR, your baseline (pre-treatment) BMR may affect how long testosterone esters stay in your system after your final injection. Individuals with a high BMR are burning more energy at rest and tend to eliminate drugs quicker than those with a low BMR.

It is possible that the higher your BMR, the quicker you should expect to eliminate a particular testosterone ester post-ingestion. The degree to which BMR affects testosterone ester elimination isn’t fully understood, but is likely to play a minor role.

An individual with a high BMI may exhibit a different elimination half-life of testosterone esters compared to a low BMI user

Plasma proteins: Concentrations of plasma proteins such as SHBG (sex-hormone binding globulin) and albumin may determine the pharmacokinetics of testosterone esters. As SHBG concentrations increase, unbound testosterone is known to decrease.