Testosterone optimization or replacement is usually done by injection, pellets, topical creams/gels, and in rare cases, nasal sprays. These forms of administration can be used in both male and female patients.
Testosterone injections deliver testosterone into the muscle. The testosterone is then absorbed directly into the bloodstream over time. The absorption period depends on the type of testosterone injected. Injections usually take place in the thighs, glutes, or deltoid muscles.
Four Most Common Types of Injectable Testosterone
The most common forms of injectable testosterone for testosterone replacement therapy (TRT) include:
- testosterone enanthate (TE)
- testosterone cypionate (TC)
- testosterone propionate (TP)
- testosterone undecanoate (TU)
Testosterone enanthate and testosterone cypionate are modified forms of testosterone. Specifically, a carboxylic acid ester has been added to the 17-beta-hydroxyl group. This attachment makes TE and TC less polar than free T. As a result, they have longer half-lives and are absorbed more slowly from the injection area. Once in the bloodstream, the ester is removed to yield free (active) T. Due to their long half-lives, both TE and TC provide a sustained release of testosterone into the bloodstream for one to two weeks. As a result, testosterone injections of TE or TC need only be administered every week or every other week.
Half-Lives of Testosterone
Half-life is the time it takes the body to metabolize and clear half the concentration of testosterone. It can depend on a person’s rate of metabolism, so it may vary. Testosterone enanthate and testosterone cypionate both have a similar half-life of roughly 5-8 days. As a result, users need only inject every week or every 10 days.
Testosterone Propionate is faster acting. It typically peaks in the blood within hours and can be fully metabolized in three days. Its half-life is around 2-3 days, so injections are typically administered every 2-3 days to maintain consistent levels. Since it metabolizes quickly and needs to be administered frequently, it’s useful for stabilizing and optimizing blood Testosterone levels in a short time.
Testosterone Undecanoate is available as brand name AVEED®. This ester is one of the longest-acting, with studies showing that Testosterone levels remained elevated for roughly three months post-injection. Injections are typically every 90 days, and protocols vary based on the patient’s response. There are some compounding pharmacies that do make this type of testosterone.
Testosterone creams/gels have half-lives ranging from 9-20 hours, which is why they are administered daily.
Dosing Regimens for TRT
Weekly injections are preferred because more frequent injections lower fluctuations in serum testosterone. About 30% of men treated for low testosterone use testosterone injections.
The recommended dosing regimen of testosterone enanthate or testosterone cypionate for testosterone therapy is 100 to 200 mg every week or 150 to 400 mg every other week.
Testosterone propionate is dosed every 2-3 days, and testosterone undecanoate is dosed approximately every 90 days.
Creams/gels are dosed daily, and pellets insertions are usually done every 3-4 months.
Pros of Testosterone Injections
- Injectable testosterone can be self-administered. The two most common forms (testosterone enanthate and testosterone cypionate) are both brand-name and generic medications in the United States. They both can also be compounded at a compounding pharmacy.
- Dosages can be changed with each injection, if necessary, to achieve optimal concentrations. Often testosterone injections can be given twice a week in a split dose to reach optimal blood levels without too much fluctuation between injections.
- Testosterone enanthate and testosterone cypionate only need to be injected every week or every other week. Also, a longer-lasting version, testosterone undecanoate, is now available in the US. The FDA approved injectable testosterone undecanoate in 2014. It will extend the period between injections to ten weeks after an initial ramp-up period.
T levels can fluctuate between doses. Fluctuations in testosterone are not fun and sometimes need to be worked out with your doctor. These fluctuations can affect mood, emotional stability, and sexual activity. Shortening the interval between injections and lowering the dosage proportionally can minimize this cyclical nature of highs and lows. The longer-lasting version of injectable testosterone, testosterone undecanoate, maintains T levels in normal ranges.
Following injections of testosterone enanthate or testosterone cypionate, T levels can exceed normal physiological levels for the first two to three days. Levels then steadily decline to below normal before the next injection. Shortening the interval between testosterone injections and lowering the dose can minimize this cyclical nature of highs and lows. This is why weekly injections of 100 to 200 mg are preferred to every other week of 150 to 400 mg.
Of note, another testosterone ester, testosterone undecanoate, has been approved that maintains T levels in normal ranges. Testosterone injections are more likely to cause an increased red blood cell count than other forms. Men using injectable testosterone should be vigilant with their physician in monitoring for this particular problem. A simple measure of your red blood cell count can alert your physician of this problem, which can then be treated. Lowering the injectable dosage and shortening the time between injections may potentially reduce the possibility of this side effect. Injection site pain is relatively common in the beginning, although injection site pain rarely indicates a problem. You need to visit a physician for testosterone injections if you're unable to self-administer at home.
Transformyou's Approach to Testosterone Replacement Therapy
Our approach is simple. We only use commercial brand name testosterone. It’s reliable, FDA approved, it won’t expire, and you take it home with you. You never have to wonder where your testosterone comes from, and we show you how to give the shot to yourself. Some patients have used testosterone blends from compounding pharmacies, which offer some variety, and we can also accommodate that.
There will be follow-up labs 7-8 weeks after you start and maybe more until we fine-tune your dosage. After that, it’s every 6-12 months. If you feel great and the numbers look good, there is no need for additional labs unless you want them. We operate with a concierge-style approach; you only work with a physician, and we are always available for questions, follow-ups, or consults. It’s all included. If you factor in all the time and money you’ve spent going to those other clinics, our services are usually more affordable.
At Transformyou, we are dedicated to our patients' health and safety and work to avoid all negative side effects. We also only recommend and use bio-identical hormones for all our hormone replacement therapies.
The Controlled Substances Prescription Monitoring Program (CSPMP) is a program developed to promote public health and welfare by detecting diversion, abuse and misuse of prescription medications classified as controlled substances under the Arizona Uniform Controlled Substances Act. Every Physician who possesses a DEA registration must also possess a CSPMP registration issued by the Arizona Board of Pharmacy. At transformyou we adhere to Arizona's CSPMP policy before prescribing a controlled substance to any patient.
Call 480-839-4131 or fill out a consultation request form to schedule your initial consultation regarding testosterone replacement therapy. All patients always work directly with one of our licensed physicians to ensure patient safety and confidentiality.