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Testosterone Injections
An effective and economical replacement option



Men's Health


Testosterone Replacement Therapy


Testosterone Injections

Testosterone Injections
An effective and economical replacement option
Testosterone Replacement Therapy Defy Medical 04
Testosterone Injections: an affordable, convenient, and effective option

Testosterone injection therapy is one of the most commonly used and effective testosterone delivery systems. Testosterone injections allow for careful control of hormone levels and fast response to physician-guided adjustments.

Testosterone is administered by injection using a small needle designed to deliver testosterone under the skin or in the muscle. Testosterone is time-released, depending on the type of injection used, and releases slowly from the injection site over a period of 2-14 days. Injections are usually given weekly and are easy to self-administer.

When you become a Defy patient, you'll work with expert providers who are up-to-date in the latest testosterone injection therapy protocols. Defy patients also receive access to our online patient portal, which offers a full catalog of injectable options and supportive medications shipped directly to your door.

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All options are available in grapeseed oil (GSO)

*only available for in-office injections. Undecanoate is not available in GSO

Which type of injection is the right one?

Your physician will discuss all options, including what ester(s) might be most effective for you. You may change or alternate different injections based on your response to treatment.

Testosterone Cypionate, Propionate, and Enanthate: Similarities and Differences

Testosterone cypionate and enanthate are the most common esters prescribed in the US. Both esters became available for use during the 1950s and have been the most popular options for injection therapy since. Both are similar in release and require a minimum of one injection per week to maintain serum testosterone levels.

Cypionate and enanthate can be administered in more frequent subcutaneous injections (2-3 injections per week) which is preferred by some patients who want more stable levels with fewer peaks.

Testosterone cypionate releases testosterone over 8 days with small amounts remaining for up to two weeks. Injections are usually administered every 3-4 days or every 7 days.

Testosterone enanthate releases testosterone over 4.5 to 8.5 days with small amounts remaining for up to two weeks. Injections are usually administered every 3 days or every 5-7 days.

Testosterone propionate is a faster acting ester which can peak in the blood within hours and be fully metabolized over 2 to 4.5 days. Injections are commonly administered every 2-3 days to maintain serum T levels and prevent rapid decline of hormone.

Since it metabolizes so quickly and needs to be administered frequently, it is easy to stabilize levels and optimizes blood-testosterone-levels quickly. However, frequent injections make propionate impractical for many patients who want to avoid more injections.


Single-dose pharmacokinetics of testosterone propionate in seven hypogonadal patients. Closed circles, mean± SEM of testosterone serum concentrations actually measured; curve, best-fitted pharmacokinetic profile.



Cypionate and enanthate

Comparative pharmacokinetics of 194mg of testosterone enanthate and 200mg of testosterone cypionate after intramuscular injection to 6 normal volunteers. Closed circles, mean ± SEM of testosterone enanthate kinetics; open circles, mean ± SEM of testosterone cypionate kinetics.



Undecanoate (injection)

Serum concentrations (mean ± SEM) of testosterone after single-dose intramuscular injections of 1000mg testosterone undecanoate in tea seed oil in 7 hypogonadal men (squares) or castor oil in 14 hypogonadal men (circles). Broken lines indicate normal range of testosterone (adapted from Behre et al. 1999a, reproduced by permission of the European Journal of Endocrinology


Different Types of Injections Esters

The most common testosterone replacement used worldwide is testosterone injection. It’s also the oldest and most economical way to increase blood levels of testosterone. Testosterone for injection is available in a variety of strengths and combinations.

What is Esterified Testosterone?

Esterified testosterone is used in injectables to create a timed release from the injection site.

An 'ester' is a chain composed of hydrogen, carbon, and oxygen atoms. This chain is attached to the testosterone molecule and must be broken down, which creates a timed release in the body once injected.

Even though the testosterone molecule remains the same no matter the ester, each one can produce different effects by the way they are metabolized in the body.

Some esters like propionate have a faster onset of action, stronger peak, and are metabolized over a shorter time. Other esters, like cypionate, have a slightly longer duration while other esters, like undecanoate, release over even longer periods of time (more than 30 days).

The most common injectable testosterone esters prescribed in the US include:
• Cypionate
• Propionate
• Enanthate
• Undecanoate
• Compounded formulation containing two or three different esters


Benefits of compounded testosterone injections

Defy Medical uses an FDA registered outsourcing facility and 503b compounding pharmacy that manufactures sterile testosterone products in a variety of strengths and combinations while following usp 797, 800, and cGMP standards. Every batch of injectable testosterone is independently tested for sterility, potency, and endotoxins before becoming available for dispensing.

Access to the right compounding pharmacy has additional benefits:

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Access to a variety of testosterone esters not available at retail pharmacies

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Access to compounded ester combinations (ex. Cypionate + propionate)

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Use of less viscous Grapeseed oil which is better for subcutaneous injections and reportedly causes less irritation than commercial cottonseed oil

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Custom strengths and concentrations make it easier to use in off-label therapies including replacement therapy in women

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Access to additional androgen therapies including nandrolone decanoate

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By using a 503a/503b outsourcing facility that follows USP and cGMP quality control standards, we can guarantee the highest level of quality assurance

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Medications can be shipped anywhere in the US directly to the patient, delivering true concierge service for convenient managed care

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Access to robust selection of support medications like HCG, FSH, anastrozol, PDE5 inhibitors, and Trimix

Injection Support

Patients prescribed testosterone will have access to everything needed to administer a testosterone injection.

Our pharmacy will ship testosterone and all necessary supplies directly to the patient, anywhere in the US. Each package contains storage and injection instructions. Additional injection references including videos will be provided.

Every patient has access to dual support from a clinical pharmacist or medical provider. Our support team is always available to assist with patient injections or the storage of medications.

Local patients can also visit the Tampa-based Defy Medical clinic to receive injections by a medical provider. Testosterone will be supplied at the clinic.  It takes less than 5 minutes to receive an injection.

Learn more about how to inject testosterone. 

More information About Testosterone Injection Therapy

The primary goal of testosterone replacement therapy is to improve and maintain physiologic serum concentrations of the hormone and its active metabolites, without significant side effects or safety concerns.

There are different testosterone replacement options approved by the U.S. Food and Drug Administration (FDA). Some are sold under a brand name in retail pharmacies and others can be compounded in unique dosage forms by compounding pharmacies.

Subcutaneous Injections
Self-Administered Subcutaneous Injections

Testosterone injections are easy to administer and typically require less than 5 minutes.

Evidence shows that small subcutaneous (under the skin) testosterone injections may also be effective to increase testosterone in hypogonadal men.

For a long time, it was thought that oil-based testosterone medications could only be administered intramuscularly (IM) using a longer 1” to 1.5” needle. Over the years, physicians who specialize in prescribing testosterone therapies noticed that testosterone levels still increased when patients administered their testosterone under the skin using a smaller needle. Multiple studies support subcutaneous administration of testosterone.

Testosterone cypionate in grapeseed oil is commonly preferred for subcutaneous injections due to low viscosity of grapeseed oil compared to other common oils. Testosterone enanthate can also be administered subcutaneously.

In 2019, the FDA approved a new testosterone drug called Xyosted which is the first subcutaneous testosterone auto-injector pen for symptomatic patients with low testosterone levels. Xyosted contains testosterone enanthate in three strength options.

Testosterone propionate might be too irritating to the injection site due to the propionic acid. A 5/8” min needle is recommended for injections containing propionate.

Combination Therapy

Defy Medical offers a compounded injection that combines slow and fast metabolizing esters to provide unique pharmacokinetics, resulting in more options for our patients.

There are some patients who respond better to a combination of two or more esters, usually consisting of esters with different half-lives. This can result in an immediate increase in testosterone followed by a delayed release of a longer ester.

Injection frequency can be adjusted to further change the serum levels. The most prescribed combination products are testosterone cypionate/propionate and testosterone cypionate/enanthate/propionate in different strengths.

Testosterone can also be combined with less aromatizing androgenic hormones like nandrolone decanoate, creating a single injection product that allows for the convenient administration of two or more hormones.

What About Testosterone Undecanoate?

Although testosterone undecanoate was discovered during the 1970s, it was only recently FDA approved in the US as another option to treat hypogonadism.

As of 2019, testosterone undecanoate is under patent protection and only available as a commercial pharmaceutical product called AVEED®.

Without insurance coverage, AVEED® can be expensive and cost-prohibitive to maintain. When insurance does cover AVEED®, it often limits the dosage allowed which results in most patients being underdosed or having to pay out of pocket for the remaining dose.

Studies support testosterone levels remaining elevated for roughly 3 months post injection, however as with other esters once can assume not all patients will respond the same. Some may require more frequent injections of testosterone undecanoate to maintain serum levels including injections every 30 days.

Insurance limitations prevent patients from receiving personalized care when using testosterone undecanoate. Until there are alternative products available and/or the cost reduces significantly, testosterone undecanoate will probably not be a commonly used for men who need replacement therapy.

Testosterone Injection Therapy for Women

Testosterone therapy can be incredibly beneficial for women, as well. Women typically produce less testosterone than men, but the hormone still plays many important functions throughout the female body. Women of all ages can experience a testosterone deficiency, in the same way that men of all ages can experience hypogonadism. 

Compounded testosterone options include injectable testosterone in lower strengths (50mg/ml) for use in women who need replacement therapy. Testosterone cypionate can be injected once per week using a small subcutaneous needle. 

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Timeline highlights
  • Berthold noted that capons (castrated roosters) who were supplemented with testosterone behave liked normal roosters again “They crowed quite considerably and showed a normal inclination towards other hens.”
  • After its chemical isolation and synthesis, testosterone was introduced into clinical medicine and used to treat hypogonadism
  • 1935 -1954 produced the most commonly used timed release esters including propionate, cypionate, and enanthate.
  • 1938 — Pellet implants containing testosterone were first reported.
  • From the late 1950s to 1970s, interest in chemically modified androgen preparations was abandoned.
  • In various preparations, testosterone has been available for over 6 decades. It is one of the oldest drugs that remain in clinical use today.