The clinic that sells you four things is usually selling one that works and three that have never been tested.
Testosterone and peptides get bundled together, and they sit in quite different evidential positions. Testosterone has real randomised trials behind it. What gets sold alongside it mostly has nothing.
So what did those trials find? Something narrower than the advertising, and more interesting than the dismissal.
Does testosterone therapy actually work?
The Testosterone Trials are the best evidence that exists. Seven coordinated placebo-controlled studies, 790 men aged 65 and over, all with measured testosterone below 275 ng/dL and symptoms. Treatment raised them into the mid-normal range for young men.[^1]
Sexual function improved, significantly and consistently. Sexual activity, libido and erectile function all moved.
Vitality and physical function did not move at all.
That split matters, because the marketing sells energy and strength and the trial found neither. Our guide on peptides after 65 documents the same shape in a different compound: a marker moved and the thing people wanted did not.
A second large trial, T4DM, ran two years in 1,007 men aged 50 to 74 with a larger waist and low-normal testosterone. It found a real reduction in type 2 diabetes risk, which is a genuine result, and no effect on depression.[^2]
Will you notice a difference?
The T4DM sexual function analysis reported something rarely quoted.
Across the group, all five measured domains improved. But clinically significant improvement in erectile function occurred in 3% of men, and in sexual desire in 10%.[^2]
Statistical significance across a thousand men and a noticeable difference to you are different claims. The trials support the first. The second happened to roughly one man in ten for desire, and one in thirty for erections.
Nobody selling this quotes those two figures, and they are the ones that answer the question a man in his forties is actually asking, which is whether he would notice.
Why the evidence and the prescriptions do not match
Testosterone prescribing grew from around $100 million in 2000 to nearly $2.7 billion by 2013, and the majority of prescriptions are written for men aged 40 to 64.[^3]
The trials were mostly conducted in men 65 and older with unequivocally low levels.
So the evidence base and the prescription base do not overlap well. That does not mean treatment in a 45-year-old is wrong. It means the confident claims being made about it are extrapolated from a different population, and the man being treated is usually not told that.
There is also a diagnostic question underneath. Somewhere between 20 and 30% of men over 50 fall below common reference ranges, and only around 6 to 12% have symptomatic deficiency.[^7]
The guidelines are firm about what follows. The American Urological Association grades the two-measurement rule as a strong recommendation at its highest evidence level. Two tests, separate days, both early morning.[^7]
One number explains why. Around 30% of men whose first reading falls in the hypogonadal range are normal when it is repeated.[^8]
There is a second reason, and it is stranger. When 1,133 laboratories using fourteen different assays measured the same quality control sample from a single hypogonadal man, the results ranged from 45 to 365 ng/dL.[^8]
So a single number from a single lab is weaker evidence than it looks. A clinic that treats one reading as a diagnosis is skipping the step the guidelines are firmest about.
Do the peptides sold with testosterone work?
Nobody knows, because almost none of them has been tested in people. It is worth being specific about which.
CJC-1295, ipamorelin, tesamorelin, sermorelin and MK-677 are the compounds usually offered alongside testosterone in this market. Our growth hormone roundup sets out what each has behind it, which for most of them is animal work and mechanism.[^8]
Where human trials exist, they mostly found what the testosterone trials found. Body composition moved. Function did not. That pattern is consistent enough across this whole category to be worth expecting.
BPC-157 appears in these bundles too, usually for joints, with no completed human trial of any kind. Our guide on BPC-157 and TB-500 covers what is behind that one.
None of that makes them useless. It makes them unproven, which is a different claim, and it means the confidence in the sales conversation is not coming from the evidence.
Is testosterone bad for your heart?
Most men arrive with this concern, and the answer changed recently in a way the headlines got half right.
TRAVERSE, published in 2023, enrolled 5,246 men aged 45 to 80 with symptoms of hypogonadism and two morning testosterone measurements below 300 ng/dL. Everybody in it either had cardiovascular disease or was at elevated risk, which makes it a deliberately hard test.
Major adverse cardiovascular events occurred in 7.0% of men on testosterone and 7.3% on placebo.[^4]
Three qualifications sit around that result, and the last is the one that matters most here.
It was a non-inferiority trial. It was built to show testosterone is no worse than placebo, which is a different claim from showing it helps your heart, and the second was never put to the test.
Some non-cardiac signals went the other way. Atrial fibrillation ran higher on treatment, 3.1% against 2.4%, and pulmonary embolism was higher too. The trial authors and subsequent reviews treat these as warranting attention rather than contraindication.
The FDA's response on 28 February 2025 was narrower than reported. It recommended three things: adding the TRAVERSE results to all testosterone products, removing the boxed warning language about increased cardiovascular risk, and retaining the limitation of use language for age-related hypogonadism. Separately, from the blood pressure studies, it required a new warning about raised blood pressure.[^5]
One warning came out and another went in.
That retained limitation is easy to miss and hard to overstate. The label still says testosterone is not indicated for the thing the midlife market sells it for, and the trial that cleared its cardiac safety enrolled men with measured deficiency and symptoms rather than men who felt tired at 47.
Two footnotes to the headline. Topical gels still carry a boxed warning for secondary exposure to children, so these products did not stop carrying boxed warnings altogether, and testosterone remains a Schedule III controlled substance.
This part is currently moving
In mid 2026, the Department of Health and Human Services requested class-wide label updates that would remove the age-related limitation entirely. Its stated basis is that the evidence no longer supports that language.[^6]
That request has not been implemented at the time of writing. If it is, the sharpest point above changes: the label would stop saying what it currently says about age-related decline, and treatment in a 45-year-old would move from off-label to within the approved indication.
Worth watching, because the position set out above is a snapshot of a moving target.
What worked without the drug
Buried in the T4DM analysis is a finding worth more than the drug result it sits beside.
Independent of testosterone treatment, reductions in waist circumference were associated with improved erectile function. And reductions in depression scores correlated with better sexual function.[^2]
That is not a moralising point about diet and exercise. It is that in a trial designed to test a drug, the non-drug variables moved the same outcomes, in the same men, at the same time.
Weight, sleep and depression all suppress testosterone and all affect the symptoms attributed to low testosterone. Addressing them is unglamorous, has better evidence than most of what is sold in this space, and is usually not what the clinic leads with.
Could your symptoms be something other than low testosterone?
Fatigue, low mood, poor sleep, weight gain, low libido and thinning motivation at 45 are the symptom list for low testosterone. They are also the symptom list for several other things, most of which are more common and all of which are treatable.
Depression. Sleep apnoea, which is badly underdiagnosed in men and produces exactly this picture. Thyroid disease. Iron deficiency. Excess alcohol. Chronic sleep restriction from young children or shift work.
Two of those deserve particular attention because they also suppress testosterone directly. Sleep apnoea and obesity both lower it, which means a low reading can be the consequence of an untreated condition rather than the cause of how you feel.
A clinic that measures testosterone finds testosterone. That is not a criticism of anybody's competence, it is what happens when the panel is built around one answer, and it is the strongest argument for having this conversation somewhere that has no product attached.
How TRT clinics make money
Worth understanding, because it explains the shape of what you are offered.
A telehealth or wellness clinic assesses you, prescribes, and ships. Revenue comes from the prescription and the subscription. Our guide on telling your doctor covers why a prescriber who is also a seller is not a neutral source on whether you should be taking something.
The peptides are usually where the margin is. Testosterone is cheap and generic; the compounds around it are neither.
And the panel they run is often broad. A broad panel produces more numbers, more numbers produce more findings outside a reference range, and each of those supports another recommendation. Our bloodwork guide covers what is actually worth measuring and why a baseline matters more than a comprehensive panel.
None of which means these clinics are frauds. Plenty do competent work, and they reach men that primary care serves badly. It means the incentive runs one way and the conversation is shaped accordingly.
What to do with all of this
Get the diagnosis before the treatment
The standard is two early-morning total testosterone measurements plus symptoms, which a single afternoon reading falls well short of.
Ask about each item separately
Testosterone has an answer. The peptides mostly do not, and asking item by item makes that visible in a way asking generally does not.
Ask what happens to your own production
Exogenous testosterone suppresses it, fertility is affected, and coming off is harder than going on. That conversation should happen before the first injection.
Understand what coming off involves
Exogenous testosterone suppresses your own production by shutting down the signal from the brain that drives it. Suppression is how the drug works, not an unwanted extra that comes with it.
Recovery after stopping takes months, varies between individuals, and may not be complete. Longer use and higher doses both slow it further. Restart protocols exist and are a prescribing matter rather than something to improvise.
So this is a harder decision to reverse than to make. That asymmetry deserves to sit in the room before the first injection, not three years later.
Get a second opinion from someone who sells nothing
An endocrinologist or your own doctor is looking at the same numbers without a subscription attached.
Address the unglamorous variables in parallel
Not instead, in parallel. The trial evidence for waist circumference affecting these outcomes is as good as the trial evidence for the drug.
What to ask if you are already on TRT
Most of the above is written for somebody deciding. Plenty of men reading this are three years into a subscription with four vials in the fridge, and nothing here is an argument for stopping abruptly.
Do not stop abruptly on your own
The one firm instruction on this page. Suppression is real and unmanaged withdrawal leaves you with neither your own production nor the replacement, which is why stopping belongs in a prescriber conversation.
Separate the items
Ask which of the four things you are paying for has trial evidence. Testosterone has an answer. The rest mostly do not, and dropping the unproven ones is a different decision from stopping treatment.
Ask what your numbers are doing
Haematocrit, blood pressure and PSA are the standard monitoring, and the blood pressure one is newly emphasised on the label. Our bloodwork guide covers what a baseline is for.
Ask about what was never investigated
If sleep apnoea, thyroid, iron or depression were never assessed before you started, they are still worth assessing, since being on treatment closes off none of them.
Ask what the exit looks like
Before you need it, not at the point where you do.
Where this stops being useful
Whether you personally have low testosterone, which needs measurement and a clinician.
Whether treatment would help you, which depends on your numbers, your symptoms and your history.
What any particular clinic is offering, since the market varies enormously and the label on the door says little.
Common questions
Does testosterone therapy work?
For sexual function in men with measured deficiency and symptoms, yes, with good trial evidence. For energy and physical function, the largest trial found no improvement. The advertising reverses that emphasis.
Will I notice a difference?
The right question, and the answer is a coin flip weighted against you. In the T4DM trial, clinically significant improvement occurred in 10% of men for sexual desire and 3% for erectile function, despite the group averages moving.
Do I have low testosterone?
Between 20 and 30% of men over 50 fall below common reference ranges and only 6 to 12% have symptomatic deficiency. Two early-morning measurements plus symptoms is the standard. One number on its own diagnoses nothing.
What about the peptides my clinic offers?
Ask about each separately. Testosterone has randomised trials. CJC-1295, ipamorelin, sermorelin and MK-677 mostly have animal work and mechanism, and our growth hormone roundup sets out what each has.
Is my clinic ripping me off?
Not necessarily, and the incentive is worth seeing clearly. Testosterone is cheap and generic; the peptides carry the margin. A prescriber who is also a seller is not neutral on whether you should be taking something.
Will testosterone affect my fertility?
Yes. Exogenous testosterone suppresses your own production and affects sperm production. If fertility matters to you now or later, raise it before starting, not after.
Is testosterone bad for your heart?
TRAVERSE, 5,246 men at elevated cardiovascular risk, found major adverse cardiac events in 7.0% on testosterone against 7.3% on placebo. The FDA removed the boxed cardiovascular warning in February 2025. It also added a blood pressure warning and kept the statement that these products are not indicated for age-related low testosterone.
Could my symptoms be something else?
Very possibly. Fatigue, low mood, poor sleep and low libido also describe depression, sleep apnoea, thyroid disease, iron deficiency and excess alcohol. Sleep apnoea and obesity also lower testosterone directly. A low reading is sometimes a consequence.
How hard is it to come off?
Harder than starting. Your own production is suppressed while you are on it, recovery takes months, and it is not guaranteed to be complete. Longer use makes it slower, and restart protocols are a prescribing matter.
I am already on it. What should I ask?
Which of the items you pay for has trial evidence, what your haematocrit, blood pressure and PSA are doing, whether the alternative causes were ever investigated, and what stopping would involve. Whatever you decide, do it with the prescriber rather than alone.
What has the best evidence in this whole area?
Losing weight, treating depression and sleeping properly. In the drug trial itself, those variables moved the same outcomes independently of treatment.
Can I just try it and see?
Coming off is harder than going on, because suppression takes time to recover and is not always complete. That makes a trial-and-see approach more consequential than it sounds.
Sources
[^1]: Snyder PJ, et al. Effects of Testosterone Treatment in Older Men. New England Journal of Medicine 2016;374:611-624. Peer-reviewed randomised placebo-controlled trials, abstract and discussion read at source. Seven coordinated trials in 790 men aged 65 or older with two morning fasting testosterone measurements averaging below 275 ng/dL plus one or more associated conditions. Testosterone gel raised serum concentrations into the mid-normal range for young men over one year. Treatment significantly increased sexual activity, libido and erectile function, p<0.001. There was no improvement in vitality or physical function. The authors note the intentional limitation that results apply only to men 65 or older with unequivocally low testosterone.
[^2]: T4DM (Testosterone for Diabetes Mellitus) trial and its secondary sexual function analysis. Peer-reviewed randomised controlled trial, abstract read at source. 1,007 men aged 50 to 74 with waist circumference 95 cm or greater and baseline testosterone 14 nmol/L or below, treated for two years. The primary trial found testosterone reduced type 2 diabetes risk. The secondary analysis of 792 participants with complete International Index of Erectile Function-15 data found testosterone improved all five domain scores, with no impact on depression. Clinically significant improvement occurred in 3% of men for erectile function and 10% for sexual desire. Independent of treatment, reductions in waist circumference were associated with improved erectile function, and reductions in depression scores correlated with better sexual function.
[^3]: Bhasin S, et al. Testosterone replacement in aging men: an evidence-based patient-centric perspective. Journal of Clinical Investigation, 2021. Peer-reviewed review, read at source. Records that testosterone prescription sales grew from approximately $100 million in 2000 to nearly $2.7 billion in 2013, and that a majority of prescriptions are written for men aged 40 to 64. Concludes that because of the lack of evidence of long-term safety and limited evidence of long-term efficacy, testosterone treatment of all older men with low testosterone levels is not justified.
[^4]: Lincoff AM, Bhasin S, Flevaris P, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. New England Journal of Medicine 2023;389(2):107-117. Peer-reviewed randomised placebo-controlled non-inferiority trial. 5,246 men aged 45 to 80 with symptoms of hypogonadism and two separate fasting morning testosterone measurements below 300 ng/dL, all with existing cardiovascular disease or elevated cardiovascular risk. Major adverse cardiovascular events occurred in 7.0% on testosterone against 7.3% on placebo, hazard ratio 0.96, 95% CI 0.78 to 1.17, p<0.001 for non-inferiority. Non-MACE signals included atrial fibrillation at 3.1% against 2.4% and higher pulmonary embolism, which subsequent position statements describe as warranting vigilance rather than contraindication. The trial was designed to test non-inferiority and not superiority.
[^5]: FDA. FDA issues class-wide labeling changes for testosterone products, 28 February 2025. Regulatory announcement, read at source. Following review of the TRAVERSE trial and required postmarket ambulatory blood pressure monitoring studies, the FDA recommended adding the trial results to all testosterone products, retaining "Limitation of Use" language for age-related hypogonadism, and removing language from the Boxed Warning related to an increased risk of adverse cardiovascular outcomes. Led by the ABPM results, it additionally required a new blood pressure warning. Topical gels retain a separate boxed warning for secondary exposure, and testosterone remains a Schedule III controlled substance.
[^6]: HHS request for class-wide testosterone labeling updates, 2026. Reported in the clinical trade press. The Department of Health and Human Services has requested class-wide prescribing information updates for testosterone products, including removal of the longstanding limitation of use for age-related hypogonadism, on the stated basis that the agency's review found the limitation no longer supported by available evidence. Not implemented at the time of writing; checked at each review, because implementation would change the central argument of this page.
[^7]: Prevalence of testosterone deficiency and symptomatic hypogonadism. Reported across the reviews cited above and in the European Male Ageing Study literature. Between 20% and 30% of men aged 50 and above present serum testosterone below commonly applied reference ranges, while symptomatic testosterone deficiency is reported in the range of 6% to 12%. Guideline thresholds vary between approximately 280 and 350 ng/dL.
[^8]: Evidence base for the peptides offered alongside testosterone. See our growth hormone roundup, which carries the primary citations for CJC-1295, ipamorelin, tesamorelin, sermorelin and MK-677, and our guide to BPC-157 and TB-500. No completed human trial exists for BPC-157. Where human trials exist for the growth hormone secretagogues, the pattern of body composition changing without functional improvement is documented in the trials cited on our peptides after 65 guide.