A Comprehensive Library of Essential TRT Information
Starting your journey on testosterone replacement therapy can be a daunting one. Whilst the benefits of TRT can be huge, there is lots of information to take in before you get started.
We’ve compiled some of the most useful information here for you to read through, it is co-authored by our Medical Director and TRT Expert Dr Chris Airey.
If you can’t find what you are looking for here, please make your way over to the TRT MANUAL to read more articles on the topic.
If you have any further questions regarding TRT then please click here to contact one of our advisors who will be happy to help.
What is TRT?
TRT stands for Testosterone Replacement Therapy. This is the replacement of a man’s natural testosterone production when it is lower than it should be.
Replacement usually occurs through the use of testosterone medication (exogenous testosterone) that is provided through either injections, pellets, patches, or gel.
In TRT clinics there are usually several different options that you can choose from. Nowadays it is also common to have other medications such as HCG included in TRT to fully optimise the treatment by preserving your fertility and natural testosterone production.
Other hormones such as oestrogen may need to be managed further with the use of other medications. The medications required during treatment vary from individual to individual, and different men respond well to different options.
The use of other medications including HCG to maintain natural testosterone levels, has led some to rename the treatment Testosterone Optimisation Therapy, as natural production remains present and isn’t being replaced.
What does testosterone do in the body?
Testosterone is the male sex hormone responsible for male characteristics and health. It is important for various functions in the human body, in both men and women!
• Testosterone improves sexual function, mainly through changes to sexual drive (libido) which can also impact erectile function.
• Muscle growth is improved by increased testosterone levels, which also improves general strength. This occurs through ramping up of both protein synthesis, tendon strength and neurological changes that affect force production.
• Cognitive function, including memory, mood and mental agility, are all heavily influenced by testosterone. Men with low levels of testosterone often report reduced short term memory and ‘brain fog’ which makes thinking difficult. Men will comment that mental arithmetic is harder than usual.
• Fertility is controlled by various factors including the testosterone level inside the testicles. If testosterone is very low (usually due to genetic or pituitary issues) then men may have reduced sperm count and quality.
• Testosterone is also involved in lesser-known roles such as ensuring normal bone density, producing body hair and increasing the cardiac output of the heart. It occurs naturally to a lesser extent in females.
It is extremely important for good health and general well-being in all men but is often ostracised in the media and by some doctors for its connections to violence, aggression as well as certain health issues.
If used safely, TRT under the supervision of one of our specialist doctors can be a very effective and safe treatment. For a more in-depth explanation, click here to read our ‘What is Testosterone’ article.
Why do some men need TRT?
Testosterone levels can become low for many reasons, some of which are still not fully understood. We know that the modern man’s testosterone levels are on average 20% less than they were 20 years ago. This may be due to one, or a combination of several factors:
• Environmental factors – such as plastics and fertilisers leaching chemicals into the water supply/food
• Hormones – the contraceptive pill contains hormones which can disrupt the male hormonal system
• Anabolic steroid use – often a full recovery of the HPTA does not occur after the shutdown of natural production
• Soy consumption – phytoestrogens from some foods such as soy and mint can reduce T levels
• Stress – chronically increased cortisol production may reduce T levels
• Congenital disposition – genetic conditions can lead to low levels
• Age-related decline/andropause – testosterone levels may decrease with age
• Pesticide exposure – pesticides and other chemicals can reduce hormone production
• Obesity – increased body fat can lead to higher conversion of testosterone into oestrogen which reduces levels and suppresses testosterone production
Many of these factors are at play in the men of today. These can lead to suppressed hormone function and symptoms of low testosterone. If you notice these factors in your life then it may be time to get a test, or talk to one of our advisors today, who can help you to further identify any symptoms of low testosterone.
What is the best type of TRT treatment?
The most popular (and arguably most effective) form of TRT is via injection. However, we understand that some men don’t get on with this type of treatment. There are several options for the administration of TRT, some of which have either reduced injection frequency or none at all:
• Testosterone gels – these can have absorption issues.
• Monthly or Quarterly testosterone injections, e.g. Nebido.
• Weekly testosterone injections, typically Testosterone Enanthate or Cypionate. Testosterone Enanthate and Cypionate are the preferred treatment options for most men.
• Pellets which are inserted every 6 months.
You can read more about the best TRT protocol here.
Can TRT help to build Muscle?
Yes, if you have low testosterone levels then your muscle growth will be reduced as testosterone is an important compound for increasing protein synthesis and muscle growth.
When men go through puberty they develop more muscle mass. Testosterone is also used by bodybuilders to increase muscle mass. It is now a widely accepted fact that testosterone helps with muscle mass and therefore strength development.
In one study men who were on testosterone developed more muscle not training than men who trained but without testosterone.
This is especially important for older men who are more likely to suffer serious injuries or death from frailty. Frailty is one of the biggest indirect killers of men and women. Older men are much more likely to have low testosterone which in turn can reduce their muscle strength.
Muscle strength is indirectly correlated with the chance of falls and fractures in the elderly population.
Testosterone injections have been shown to be more effective at assisting muscle growth than gel forms of TRT.
Can TRT help with anti-ageing?
Yes, it can. New research from an Australian study of 2913 men shows that men with higher levels of oestradiol (which is produced from testosterone in men) had longer telomeres which can lead to an increased life span.
They also found that higher SHBG (sex hormone binding globulin) levels reduced telomere length. Testosterone reduces SHBG levels so it may also increase telomere length indirectly.
Anti-ageing is now big business with new compounds and treatments becoming available by the day. TRT is often used by Longevity or Anti-ageing companies in the US.
Testosterone is used alongside Human Growth Hormone (HGH) to improve general health and energy levels.
Many of our patients see improved energy, less stress, less anxiety and more vitality on TRT which can lead to better lifestyle choices and healthier living through exercise and improved mood.
Is TRT linked to prostate cancer or prostate issues?
Recent research suggests there is no link.
A recent study observing 1,500 patients concluded that higher testosterone levels may even reduce the risk of prostate cancer, and that low testosterone may increase your risk of prostate cancer.
You can read more about this on the Prostate Cancer UK website here. However, if you already have prostate cancer then starting TRT is not advised.
Men over 45 require a clear prostate exam and PSA blood test reviewed by our doctors before starting TRT in the UK as there is some evidence that higher testosterone levels can increase the growth of prostate cancers which are already there.
When men start TRT there is a phenomenon which may result in a raised PSA (prostate specific antigen) – this usually reduces within a few months of starting.
If the dose is too high and too much testosterone is converted into DHT, then some men may get Benign Prostatic Hypertrophy – growth of the prostate which isn’t linked to cancer. This can cause some issues with urination. It is usually treatable and improves with a reduced dose.
Low testosterone symptoms
• Low sex drive/libido and/or erectile dysfunction
Many men (but not all) with low testosterone suffer from erectile dysfunction. Others will notice that their sex drive has dropped. Sex drive is an important part of feeling healthy and keeping a healthy relationship. It can also improve your confidence and make you feel more energetic.
• Poor cognition/poor arithmetic/brain fog
Often one of the first benefits men who start Testosterone Replacement Therapy realise is improved clarity of thought and reduced brain fog.
TRT has been shown to improve the IQ and cognition of older men and allows many to think straight again. It provides clarity and makes decision-making more assertive and natural. This can lead to really positive changes in a man’s work environment, where men on TRT often find that they suddenly become more productive and competitive.
Many men find that TRT is the catalyst for them to start rising up the ranks at work.
Men with low testosterone often complain of low energy levels and feeling tired all the time. Falling asleep after dinner is another big indicator that you may have testosterone deficiency. TRT can have a rapid impact in improving this situation, giving you the energy of your younger self and allowing you to get more done!
• Loss of muscle mass/sports performance
Testosterone is a performance-enhancing drug. It is sometimes used illegally by athletes to get a competitive advantage over their peers. TRT is not allowed in most competitions in the UK or internationally. In sport and fitness, testosterone has many useful effects including muscle mass building, strength improvements, improving joint health and reducing body fat levels!
TRT will also improve your energy levels allowing you to work harder and see more improvements. You will be amazed at the effect TRT can have on your performance and physique.
Testosterone is always associated with competition, and for good reason! Men and women with more testosterone are more competitive, and tend to win more as a result. Without testosterone replacement therapy, competing and improving yourself can feel like a constant challenge.If you have low testosterone, starting TRT will increase your performance in sports, in competition and at work.
There are many other symptoms that you might have noticed, which may not be directly associated with low testosterone – you may have increased body fat around your waist, excessive sweating and/or night sweats (often caused by oestrogen levels), reduced or absent body and facial hair, increased breast tissue (gynaecomastia), insulin resistance, and particularly in older men: loss of bone mass (osteoporosis) and reduced circulation (cold hands and feet!)
Types of Low Testosterone
Primary hypogonadism (the testicles don’t produce enough testosterone)
In primary hypogonadism the gonads (testicles in men) don’t respond to the hormones released by the pituitary (in the brain), LH and FSH. In this instance, the testicles can’t produce enough testosterone. Often LH and FSH are raised as the body produces more to try to stimulate the testes to produce testosterone.
• Damage to the testicles/trauma
• Radiation / Chemotherapy used when treating cancer (usually of the testicles)
• Castration (removal of the testicles, often due to cancer of other issues)
• Klinefelter syndrome (a genetic issue that means a man does not have the same chromosomes as other men)
Secondary hypogonadism (also called hypogonadotropic hypogonadism)
In secondary hypogonadism, the gonads (testes) are working but the release of LH and FSH is affected. The brain isn’t telling the testes to produce enough testosterone.
• Pituitary tumours or disease (prolactinomas – this is why your doctor should test prolactin)
• Traumatic brain injury – damage to the pituitary can affect the production of hormones
• Damage or trauma to the testicles
• Radiation / Chemotherapy used when treating cancer
• Other chronic diseases like liver or kidney disease
• Obesity (raises oestrogen which tells the brain to stop producing LH and FSH)
• Nutritional deficiencies
Often there does not appear to be a reason for men having low testosterone. Many people think that it is caused by certain environmental factors in modern-day life, such as hormones in the water and the widespread use of plastic containers for storing food and drinks.
A qualified and experienced Testosterone Replacement Therapy doctor will be able to tell you which type of testosterone deficiency you most likely have and possibly even why.
LH and FSH are important to help with this diagnosis. Our doctors specialise in TRT throughout the UK, and can help with your diagnosis and treatment.
Which blood tests do I need before TRT?
Before starting TRT you need to have certain blood tests to ensure that you are safe to start this treatment as well as to show that testosterone levels are low on two occasions. These are the guidelines in most countries.
You need to have two results showing low total testosterone and/or free testosterone.
Alongside this, your doctor should make sure that you have the following values tested to ensure your safe treatment:
• Sex Hormone Binding Globulin (SHBG) – This protein binds to your total testosterone making it less available to the body. If you have a raised SHBG level, you could suffer from the symptoms of low testosterone despite good total testosterone levels.
NHS GPs rarely test for this and therefore cannot accurately tell if low testosterone is causing your symptoms. This value is also used to calculate your free testosterone level.
• Oestradiol (Oestrogen) – Oestradiol is the main active part of oestrogen. It is produced in the male body from testosterone when it is converted by aromatase (an enzyme).
If Oestradiol is too high, or too low, it can affect male libido, erection quality, emotions, fat accumulation and growth of breast tissue (which can lead to gynaecomastia, or ‘man boobs’!) This is extremely important to test before and during treatment for low testosterone!
• Follicle Stimulating Hormone (FSH) – A hormone produced by the pituitary gland that stimulates the testes to produce sperm and testosterone.
• Luteinising Hormone (LH) – A hormone produced by the pituitary gland that stimulates production of testosterone in the testicles. Luteinising Hormone and FSH are important for understanding why you have low testosterone.
• Prolactin – If your levels are high it can affect your mood and sexual health. High levels can reduce testosterone production. If your Prolactin level is very high, it may be associated with a prolactinoma, a tumour in the pituitary gland that can lower your testosterone levels. If over a certain range then the doctor may recommend that you have an MRI scan before starting treatment.
• Prostate-Specific Antigen (PSA) – This can indicate prostate health. The most recent research suggests that TRT does not increase the risk of Prostate Cancer, but it can increase Lower Urinary Tract Symptoms and potentially make prostate cancer worse if you already have it.
If this value comes back high, you may need further tests before starting TRT, including a physical examination by a doctor.
This is required for all men over the age of 45.
• Full Blood Count – TRT increases the production of red blood cells. This can increase the thickness of the blood and the chances of clotting.
If this is high or increases during TRT you may need to have some blood let to reduce your levels.
• Lipids – Certain medications can make your cholesterol, LDLs and HDLs worse. If these are particularly bad before treatment then you may need to talk to your GP before starting.
These are also reviewed whilst on treatment to ensure you are healthy.
Things we may also look at:
• Thyroid hormones – some thyroid problems present with the same symptoms as testosterone deficiency. Your doctor should check these to ensure you are not suffering from thyroid issues before starting TRT.
• Cortisol – this can indicate whether there are other issues with your pituitary gland.
• Liver function tests – Certain medications can make these worse, they can also indicate other issues.
• Renal (kidney) function – Certain medications can make these worse, they can also indicate other issues.
• Iron studies – These can indicate certain issues such as haemochromatosis, which may need further investigation before starting testosterone replacement therapy.
All of these Blood tests serve certain purposes and may be requested before starting treatment, depending on your medical and medication history.
If your doctor or pharmacy is trying to provide treatment based on just one testosterone result, then it may be worth looking for a different clinic with more thorough testing and your health as its priority.
We provide blood tests for all your needs here.
Will TRT make my testicles shrink/atrophy?
Increasing the amount of testosterone in the body from outside sources, for example through Testosterone Replacement Therapy, can cause the testicles to shrink in size by up to 75%.
Luckily, medications like HCG (Human Chorionic Gonadotropin) can be used to effectively improve testicle size back to normal whilst stimulating further production of your natural testosterone levels.
Many men also notice improvements in mood when starting HCG as it maintains a downstream of other hormones such as pregnenolone which is important for wellbeing and libido.
Will TRT make me infertile?
The addition of exogenous (not from the body’s natural production) testosterone can reduce sperm production in men.
Traditionally this meant that TRT could only be used by men who weren’t interested in fertility, or who were suffering so much that they had no choice but to be infertile for life. Luckily our clinic has access to TRT programs which are designed to include medications to stimulate the natural production of sperm by the testes.
The medication which our doctors recommend to maintain the fertility of our patients is called HCG, and has been shown to improve fertility in men. HCG is used in women to improve their fertility when undergoing IVF to increase their chances of pregnancy.
It is used in smaller, more frequent doses in men to improve their testicular function. The byproduct of this is that the testicles remain a normal size and continue to produce testosterone in most men.
This can add to the testosterone levels from TRT and also allows the production of other hormones which are usually ‘knocked out’ by exogenous testosterone use.
You can read more on TRT and fertility here. HCG should be used by almost all men on TRT.
Our medical director Dr Chris Airey encourages all men to use this medication alongside TRT as it improves fertility, maintains testicular function and stimulates other hormonal pathways important for well-being in men.
If you are concerned about your fertility levels you can get an at-home, WHO validated test from our site here.
Is TRT for life?
In most cases, men will take TRT for life. This is because it has great benefits to symptom relief, longevity, vitality and health.
Occasionally men may develop another condition which means that TRT should be stopped either temporarily or permanently. Others may not be able to get rid of certain side effects and decide not to continue treatment. Often these same men will return as they realise the low testosterone symptoms were worse than the side effect they had.
By taking TRT with HCG alongside it, men are more able to stop TRT if they have health or other issues which force it.
This means that natural testosterone production remains and men aren’t left with no ability to produce testosterone after stopping treatment.
Can I 'Cycle' on and off TRT?
No, it isn’t advisable.
Testosterone replacement therapy is meant to replace your low natural production so that you have high normal levels to relieve your symptoms.
It isn’t effective if you stop and start TRT. If you ‘cycle off’ (a term used by AAS users to describe the way they take steroids on and off for short ‘cycles’ of a few weeks) TRT then your levels will drop down to below what they were whilst they recover back to pre-TRT levels.
This leaves men with low testosterone and a return of symptoms. Levels do not stay at the same point whilst off TRT and you do not keep the symptomatic relief.
Unlike ‘cycles’ of AAS which are used to increase muscle mass and allow the body to recover its natural levels, TRT is meant to be used longterm to reduce symptoms by bringing testosterone levels into the top of the normal range and avoid side effects.
If you think you have low testosterone then contact us today and see what we can do to help you get back to normal again! We can provide advice and guidance on how to get NHS treatment, the best tests for you as well as options for TRT treatment in the UK.
Our highly experienced medical team will be happy to work with you if you are just starting your TRT journey, if you already have blood test results or even if you are unhappy with your current TRT provider and want to transfer to a more professional service.
- Wenker EP, Dupree JM, Langille GM, Kovac J, Ramasamy R, Lamb D, Mills JN, Lipshultz LI. The Use of HCG-Based Combination Therapy for Recovery of Spermatogenesis after Testosterone Use. J Sex Med. 2015 Jun;12(6):1334-7. doi: 10.1111/jsm.12890. Epub 2015 Apr 22. PMID: 25904023.
- Croes K, Den Hond E, Bruckers L, Govarts E, Schoeters G, Covaci A, Loots I, Morrens B, Nelen V, Sioen I, Van Larebeke N, Baeyens W. (2015) Endocrine actions of pesticides measured in the Flemish environment and health studies (FLEHS I and II). Environ Sci Pollut Res Int. 22(19)
- Søeborg T, Frederiksen H, Mouritsen A, Johannsen TH, Main KM, Jørgensen N, Petersen JH, Andersson AM, Juul A. (2014) Sex, age, pubertal development and use of oral contraceptives in relation to serum concentrations of DHEA, DHEAS, 17α-hydroxyprogesterone, Δ4-androstenedione, testosterone and their ratios in children, adolescents and young adults. Clin Chim Acta. 1;437:6-13.
- Rasmussen JJ, Selmer C, Østergren PB, Pedersen KB, Schou M, et al. (2016) Former Abusers of Anabolic Androgenic Steroids Exhibit Decreased Testosterone Levels and Hypogonadal Symptoms Years after Cessation: A Case-Control Study. PLOS ONE 11(8): e0161208.
- Nagata C, Inaba S, Kawakami N, Kakizoe T, Shimizu H. (2000) Inverse association of soy product intake with serum androgen and estrogen concentrations in Japanese men. Nutr Cancer. 36(1):14-8. doi: 10.1207/S15327914NC3601_3. PMID: 10798211.
- Smith,G., Ben-Shlomo, Y., et al. (2005) Cortisol, Testosterone, and Coronary Heart Disease Prospective Evidence From the Caerphilly Study Circulation. 112:332-340
- Wang Y, Gong C, Qin M, Liu Y, Tian Y.(2017) Clinical and genetic features of 64 young male paediatric patients with congenital hypogonadotropic hypogonadism. Clin Endocrinol (Oxf). 87(6):757-766. doi: 10.1111/cen.13451. Epub 2017 Sep 13. PMID: 28833369.
- Liu CC, Wu WJ, Lee YC, Wang CJ, Ke HL, Li WM, Hsiao HL, Yeh HC, Li CC, Chou YH, Huang CH, Huang SP. (2009) The prevalence of and risk factors for androgen deficiency in aging Taiwanese men. J Sex Med. 6(4):936-946. doi: 10.1111/j.1743-6109.2008.01171.
- Croes K, Den Hond E, Bruckers L, Govarts E, Schoeters G, Covaci A, Loots I, Morrens B, Nelen V, Sioen I, Van Larebeke N, Baeyens W. (2015) Endocrine actions of pesticides measured in the Flemish environment and health studies (FLEHS I and II). Environ Sci Pollut Res Int. 22(19):14589-99. doi: 10.1007/s11356-014-3437.
- Eriksson J, Haring R, Grarup N, Vandenput L, Wallaschofski H, Lorentzen E, Hansen T, Mellström D, Pedersen O, Nauck M, Lorentzon M, Nystrup Husemoen LL, Völzke H, Karlsson M, Baumeister SE, Linneberg A, Ohlsson C. (2017) Causal relationship between obesity and serum testosterone status in men: A bi-directional mendelian randomization analysis. PLoS One. 27;12(4):e0176277. doi: 10.1371/journal.pone.0176277.
- Yeap, B.B., Hui, J., Knuiman, M.W., Flicker, L., Divitini, M.L., Arscott, G.M. et al. (2020) U-Shaped Relationship of Leukocyte Telomere Length With All-Cause and Cancer-Related Mortality in Older Men, The Journals of Gerontology: Series A, 10.1093/gerona/glaa190
- García-Cruz E, Piqueras M, Huguet J, Peri L, Izquierdo L, Musquera M, Franco A, Alvarez-Vijande R, Ribal MJ, Alcaraz A. (2012) Low testosterone levels are related to poor prognosis factors in men with prostate cancer prior to treatment. BJU Int. 2012 Dec;110(11 Pt B):E541-6. doi: 10.1111/j.1464-410X.2012.11232.x. PMID: 22584031.