Body & Exercise · 11 min
Testosterone, gym supplements, and the things people sell online
Top things to know
Most 'test booster' supplements have weak evidence, and some, like tribulus, have negative evidence.
External testosterone, from TRT or steroids, shuts down your own sperm production; recovery can take months.
Sleep, strength training, body composition, and less alcohol are the best-evidenced ways to raise your own testosterone.
Proper testing means two morning blood samples with LH, FSH, and SHBG, read with your fertility plans.
What is the honest picture on testosterone products and gym supplements?
A whole industry sells products aimed at 'boosting' , ashwagandha, tribulus, fenugreek, ZMA, D-aspartic acid, 'test boosters' with proprietary blends. The marketing is confident. The evidence for most is weak, and for some (like tribulus) is actively negative.
Your testosterone is yours to plan around, TRT and natural optimisation are different tools with different costs to your timeline.
Real reversible causes of low , bad sleep, alcohol, obesity, low vitamin D, stress, respond to fixing the cause, not supplementing on top.
What is TRT really, and what does it cost your fertility?
Replacement Therapy (TRT) is a prescribed, monitored treatment for clinically-diagnosed hypogonadism (consistently low with symptoms, confirmed on two separate morning blood tests). It has a legitimate medical place.
Myth
A common belief is that TRT only affects you while you're on it, stop the dose, normal service resumes.
Evidence
Sperm production is suppressed during TRT and recovery after stopping is variable, months for many men, longer for some. The hypothalamic–pituitary–testicular axis takes time to restart. If your timeline includes wanting children at any point, this recovery window matters before the first injection, not after.
Crosnoe LE et al., Transl Androl Urol 2013; Society for Endocrinology UK guidelines on male hypogonadism 2018.
Quick check
Have you been considering TRT or thinking about going to a private clinic for testosterone?
If you ever decide to raise it
Putting it into words
No words guarantee how an appointment goes. Precise words just make sure what you live with gets described, not rounded down.
Keep it, edit it, or just remember it. Stays on your phone.
If you ever decide to raise it
Putting it into words
No words guarantee how an appointment goes. Precise words just make sure what you live with gets described, not rounded down.
Keep it, edit it, or just remember it. Stays on your phone.
What should you know before considering testosterone supplementation?
Myth
More testosterone = better fertility
Evidence
Exogenous testosterone (from supplements, injections, or TRT) signals the hypothalamus to stop the hormonal cascade that drives your own testosterone and sperm production. The result is typically azoospermia (zero sperm). Recovery after stopping is variable, months for many men, sometimes longer. Natural optimisation (sleep, resistance training, body composition, alcohol reduction) raises endogenous testosterone without suppressing the system.
Crosnoe LE et al. Exogenous testosterone: a preventable cause of male infertility. Transl Androl Urol. 2013;2(2):106–113.
Exercise types and their fertility impact
Resistance training (strength work)
3–4 sessions of compound resistance training per week (squats, deadlifts, bench press) is consistently associated with higher testosterone and better sperm parameters. The effect is pronounced in men who were previously sedentary. More sessions per week beyond 5 may begin to reduce the benefit.
Endurance training
Moderate aerobic activity (running 30–45 minutes, 3–4 days/week) improves cardiovascular function and is broadly positive for fertility. Extreme-volume endurance training (marathon-level weekly mileage consistently) can suppress testosterone through elevated cortisol and energy deficit. The threshold where benefit becomes risk varies between individuals.
HIIT (High Intensity Interval Training)
Short HIIT sessions (20–30 minutes, 2–3 times per week) show positive effects on testosterone in several studies, comparable to resistance training. The key is recovery, back-to-back HIIT sessions without adequate rest can push cortisol up and begin to negate the testosterone benefit.
Yoga and low-intensity movement
Yoga and mindfulness-based movement reduce cortisol and improve sleep quality, both of which protect testosterone. Hot yoga is an exception: core body temperature elevation can raise scrotal temperature and has some evidence for reduced sperm parameters during sustained practice.
Which of these sound familiar?
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Reviewed by clinicians
Authored and reviewed by clinicians from the founding team. Information only, not personalised medical advice.
From the team behind Her Holistic Health, founded by Dr Divpreet Sacha, NHS-trained GP.