Yaar · 11 min
Testosterone, gym supplements, and the things people sell online
3 sections · 11 min read
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?
For your doctor
I would value a structured diagnostic workup for possible hypogonadism: two morning (08:00–11:00) total testosterone measurements at least a week apart, alongside LH, FSH, SHBG, prolactin, and a calculated free testosterone. I would like the results interpreted against age-banded reference ranges and my symptom picture before any treatment decision is made.
What this is for: making sure the diagnostic picture is built properly before TRT enters the conversation. One low test at the wrong time of day is not a diagnosis. This snippet asks for the standard two-morning protocol with the right surrounding bloods.
For your doctor
Before any TRT decision, I would like to discuss the impact on spermatogenesis given the 74-day sperm production cycle. Specifically, I would value a baseline semen analysis, a discussion of fertility preservation (sperm freezing) options if relevant to my plans, and the typical recovery window for endogenous sperm production after TRT cessation.
What this is for: keeping the 74-day sperm production window in the conversation before TRT starts, not after. If fathering a child is anywhere on your timeline, the order matters: baseline semen analysis and a fertility-preservation conversation come first.
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.
How did this land with you?
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Reviewed by clinicians
Authored and reviewed by clinicians from the founding team. Information only, not personalised medical advice.