The most commonly prescribed form of testosterone replacement therapy in the United States. Here is what the internet says, what the clinical evidence actually shows, and what you should track if you are on it.
Testosterone cypionate is a synthetic form of testosterone attached to a cypionate ester. The ester slows the release of testosterone into your bloodstream after injection, giving it a half-life of approximately 8 days. This means you do not need daily injections -- most protocols call for once or twice per week.
It is the most commonly prescribed form of TRT in the United States, typically administered via intramuscular (IM) injection into the glute, quad, or deltoid, though subcutaneous (subQ) injection has been gaining traction in recent years.
Testosterone cypionate is FDA-approved for the treatment of male hypogonadism -- a clinical condition where the body does not produce enough testosterone on its own, confirmed by blood tests and symptoms. It is a Schedule III controlled substance in the US.
The claims you will encounter on Reddit, TikTok, and TRT clinic ads.
Based on the 2018 Endocrine Society guidelines, the TRAVERSE cardiovascular trial, and the Testosterone Trials (TTrials).
The Endocrine Society recommends testosterone therapy only for men with consistently low testosterone confirmed by morning blood tests AND clinically significant symptoms (fatigue, low libido, loss of muscle mass, depressed mood). Age-related decline alone is not sufficient for a diagnosis. The goal is to restore testosterone to the mid-normal range -- not to maximize it.
The typical range is 100-200mg per week, but optimal dosing depends on your SHBG levels, metabolic rate, aromatization rate, and target blood levels. Men with high SHBG may need higher doses; men who aromatize heavily may do better with lower, more frequent doses. Cookie-cutter 200mg/week protocols fail many patients. Bloodwork at 6-8 weeks, then ongoing, is the only way to dial in your dose.
TRT stimulates red blood cell production. Hematocrit can rise above safe levels (above 54%), increasing clot risk. This is the most common clinical concern and the reason hematocrit monitoring is mandatory.
Exogenous testosterone suppresses the HPT axis, drastically reducing sperm production. Men trying to conceive may need HCG to maintain testicular function, or may need to pause TRT entirely.
The TRAVERSE trial (Lincoff et al., 2023, NEJM, n=5,246) was specifically designed to answer this question. Result: testosterone therapy did NOT increase the rate of major adverse cardiovascular events (MACE) compared to placebo in men with established or high-risk cardiovascular disease. This was a landmark finding that significantly changed the risk conversation.
In genetically predisposed individuals, testosterone (via conversion to DHT) can accelerate male pattern baldness and cause acne. These are dose-dependent and individual.
Testosterone can worsen existing obstructive sleep apnea. The Endocrine Society recommends screening for sleep apnea before and during TRT.
Once-weekly injection creates a significant peak-and-trough cycle. Splitting the dose to twice per week (or every other day for some) flattens the curve, often reducing estrogen conversion, water retention, acne, and mood swings. More frequent dosing is a well-accepted clinical approach, not a "bro-science" invention.
Both subcutaneous and intramuscular injection routes deliver testosterone effectively. SubQ is gaining popularity because it uses smaller needles, is less painful, and some practitioners report lower estrogen conversion (anecdotally -- controlled data is limited). IM provides a more established absorption profile. Neither is categorically better; the choice is individual.
The Endocrine Society does NOT recommend routine aromatase inhibitor use with TRT. Many TRT clinics prescribe anastrozole by default, but this practice is not supported by guidelines. Estrogen plays important roles in bone health, cardiovascular protection, and brain function in men. Suppressing it aggressively can cause joint pain, low mood, and bone density loss. AIs should only be used when estrogen-related symptoms (gynecomastia, significant water retention) are confirmed by blood work and not manageable through dose or frequency adjustment.
Testosterone cypionate is legitimate, well-studied medicine for men with diagnosed hypogonadism. It is not a performance-enhancing shortcut, and it is not a one-size-fits-all protocol.
The TRAVERSE trial put the biggest cardiovascular fear to rest. The real, ongoing risks are hematocrit elevation, fertility suppression, and the need for lifetime monitoring once you start. The effects are real but take weeks to months -- not days.
Get bloodwork. Dial in YOUR dose. Track your markers, not someone else's protocol. That is the entire point of Dosi.
The definitive guideline for testosterone therapy in men with hypogonadism. Covers diagnosis criteria, treatment thresholds, monitoring protocols, and risk management. The standard of care that most TRT clinics should be following.
Randomized, double-blind, placebo-controlled trial in 5,246 men aged 45-80 with established cardiovascular disease or high risk. Testosterone therapy did not increase the incidence of major adverse cardiovascular events. The largest cardiovascular safety trial for testosterone ever conducted.
Seven coordinated trials in 788 men aged 65+ with low testosterone. Showed improvements in sexual function, walking distance, and mood. Effects on vitality and cognitive function were more modest. Established that benefits are real but domain-specific.
These are general ranges from clinical guidelines. Your provider should tailor dosing to your bloodwork.
100-200mg per week, split across injection days. Most clinicians start at the lower end (100-120mg/week) and titrate up based on bloodwork at 6-8 weeks. Starting high and adjusting down is more common in online clinics and more likely to cause side effects early.
Most common starting protocol. Simple but creates the largest peak-trough swing.
Increasingly standard. Cuts peak-trough variation roughly in half. Often reduces E2-related side effects.
Used by those sensitive to hormone fluctuations. Flattest blood level curve. Requires more discipline.
First labs at 6-8 weeks after starting or changing dose. Then quarterly for the first year, then at minimum every 6-12 months ongoing.
The data points that actually matter -- and what Dosi is built to help you log.
Track rotation to prevent scar tissue buildup and ensure consistent absorption.
Log every injection -- even if your protocol is stable. Dose changes over time are common.
Rate daily or weekly. Look for patterns relative to injection timing.
Total T, free T, E2, hematocrit, PSA, lipids. Compare trends across draws.
Weight, waist measurement, and visual progress. TRT shifts composition slowly over months.
Acne, hair changes, water retention, sleep quality, mood swings. Log severity and timing.
Log injections, track bloodwork, monitor symptoms, and watch your data reveal what actually works for your body. Not someone else's body -- yours.
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