Most men over 55 who walk into a clinic with complaints about energy, libido, or erections receive a single result: total testosterone. If it falls within the “normal” range, the doctor sends them home with a clean bill of health — despite still feeling like a shadow of their former selves.
The problem isn’t the testosterone. It’s the incomplete picture.
There are four specific blood markers that, when reviewed together, tell the full story of what’s happening with your hormonal health, your prostate, and your circulation. If your next blood panel doesn’t include all four, you could be optimising in the dark. This guide breaks down each one, why it matters, and how they interact — particularly for men working to improve erectile function, energy, and long-term vitality.
1. Testosterone: Total AND Free — Why Both Numbers Matter
Most blood tests check total testosterone, which measures the entire amount of the hormone circulating in your blood. But here’s the catch: proteins — primarily sex hormone-binding globulin (SHBG) — bind to a significant portion of that testosterone, locking it away so your body cannot actually use it.
Free testosterone is the unbound, active fraction your cells can work with directly. This is what drives libido, erection quality, energy levels, and muscle repair. When free testosterone is low, you feel it — even if your total testosterone looks fine on paper.
Research published in the Journal of Sexual Medicine found that men with normal total testosterone but low calculated free testosterone showed significantly worse scores on erectile function, sexual desire, and orgasmic function compared to men with normal levels of both — confirming that free testosterone is the more clinically relevant marker for sexual symptoms.
A separate PubMed study found that total testosterone alone misdiagnosed hypogonadism in more than 8% of men presenting with sexual symptoms, and that free testosterone provides a more accurate diagnosis of functional hypogonadism, particularly in men over 45 where SHBG naturally rises with age.
What this means for you: If you’ve been told your testosterone is “normal” but you’re still experiencing poor erections, fatigue, or low drive, ask specifically for free testosterone to be included. It’s the number that matters most for how you feel and function day to day.
At Shockwave Clinic, blood tests for erectile dysfunction are central to building an effective treatment plan. Free testosterone levels aren’t just assessed in isolation — they’re used to calibrate which interventions will deliver the best results. As the clinic notes, low testosterone can limit the effectiveness of any treatment, making it the essential starting point before anything else is considered.
2. Estradiol (E2) — The Hormone Men Forget About
Most men are surprised to learn they need to test estrogen. Estradiol (E2) is the predominant form of oestrogen, and while most people associate it with female physiology, it plays an essential and well-documented role in male sexual function.
Your body produces estradiol through a process called aromatisation — an enzyme called aromatase converts a portion of your testosterone into estrogen. This is completely normal and necessary. The problem arises when the balance shifts too far in either direction.
A comprehensive review published in Asian Journal of Andrology confirmed that estradiol in men is essential for modulating libido, erectile function, and spermatogenesis, with estrogen receptors found throughout the brain, penis, and testes. Crucially, the same research noted that both low testosterone and elevated estrogen increase the incidence of erectile dysfunction independently of one another — meaning either extreme causes problems.
Signs your E2 may be too low:
- Flat, low mood
- Joint discomfort
- Reduced libido
- Poor erection quality
Signs your E2 may be too high:
- Water retention
- Fatigue and emotional shifts
- Softer erections
- Reduced drive despite adequate testosterone
A meta-analysis in PLOS ONE confirmed that elevated estradiol levels are significantly associated with erectile dysfunction, supporting the clinical importance of monitoring this marker, particularly for men on testosterone therapy where aromatisation can increase.
The practical takeaway: erections depend on hormonal balance, not just testosterone levels in isolation. Estradiol is part of that balance, and it’s rarely included in a basic hormone panel. Ask for it by name.
3. PSA (Prostate-Specific Antigen) — A Marker You Should Track, Not Fear
PSA is a protein the prostate gland produces. Most people associate it with prostate cancer screening, but its clinical value extends well beyond that — it’s a useful general indicator of prostate health, including inflammation and benign enlargement (BPH).
For men over 55, and especially for those who are on or considering testosterone replacement therapy (TRT), PSA monitoring is non-negotiable. Testosterone can stimulate prostate tissue activity, which means that without appropriate oversight, it can amplify any pre-existing prostate changes.
What you’re looking for isn’t necessarily a low number — it’s a stable, non-rising number over time. Tracking PSA as a trend over months and years gives you far more insight than a single reading taken out of context. A sudden or steady rise warrants investigation — but it doesn’t automatically indicate cancer.
For men dealing with erectile dysfunction alongside prostate concerns, it’s worth noting that Shockwave Clinic offers a dedicated BPH and prostate treatment programme that combines ESWT, EMTT, and Carboxy CO₂ therapy — addressing prostate-related symptoms non-invasively.
If you’ve been exploring the relationship between TRT and ED treatment, the clinic’s in-depth guide on shockwave therapy vs TRT for erectile dysfunction is worth reading. It makes clear that prostate health monitoring is a shared responsibility between your prescribing doctor and any clinic supporting your sexual health outcomes.
4. Hematocrit — The Blood Thickness Number Nobody Talks About
Hematocrit measures the proportion of red blood cells in your blood. The higher the hematocrit, the thicker your blood. And while this might sound like a minor detail, it has direct implications for circulation, blood pressure, and — yes — erectile function.
Testosterone stimulates red blood cell production. This is one of the reasons TRT can be effective for energy and endurance. But without monitoring, it can quietly push your hematocrit too high over time, creating a paradox: the very hormone you’re optimising for sexual performance can begin to impair circulation if blood thickness goes unchecked.
High hematocrit increases the risk of clotting, raises blood pressure, and can reduce the free-flowing circulation that healthy erections depend on. Men on TRT should check hematocrit at baseline and regularly thereafter — most guidelines recommend monitoring every three to six months.
This marker is especially important if you’ve noticed that treatments or supplementation aren’t delivering the results you expected. Poor circulation is one of the most common root causes of erectile dysfunction, and it’s one of the primary targets of non-invasive shockwave therapy for ED at Shockwave Clinic. Addressing blood thickness is part of ensuring that restored circulation actually works efficiently.
Why All Four Markers Must Be Reviewed Together
Each of these four markers tells part of the story. But the real insight comes from reading them as a system.
Think of it like four components of an engine. Testosterone drives the core performance. Estradiol calibrates the balance. PSA tells you the prostate is safe to accelerate. Hematocrit determines whether the fuel is flowing cleanly.
If testosterone is high but estradiol is elevated, erection quality suffers. Creeping hematocrit will compromise circulation even when testosterone sits at an optimal level. Rising PSA without a management plan makes any aggressive optimisation strategy riskier. Missing even one marker means treating one part of a four-part system — and getting incomplete results.
This systems-based approach is exactly why Shockwave Clinic incorporates blood work into its men’s health programme for over 40s. The clinic never evaluates testosterone in isolation — clinicians always assess it alongside vascular health and prostate markers to build a full clinical picture before establishing any treatment plan.
Frequently Asked Questions
What blood tests should a 55-year-old man get for sexual health?
At minimum, a men’s health blood panel at 55 should include total testosterone, free testosterone, estradiol (E2), PSA, and hematocrit. These four markers work together to reveal hormonal balance, prostate health, and circulation — the three pillars that determine sexual performance and energy. A basic testosterone test alone won’t give you the full picture.
What’s the difference between total and free testosterone?
Total testosterone measures all testosterone in your blood, including the portion bound to proteins like SHBG. Free testosterone is the small, unbound fraction your cells can actually use. You can have normal total testosterone but low free testosterone — and still experience symptoms like erectile dysfunction, fatigue, and low libido. Free testosterone is generally the more clinically relevant marker.
Why do men need to test estradiol (estrogen)?
Estradiol is a form of estrogen that men produce naturally through the conversion of testosterone. It’s essential for libido, bone density, mood, and erectile function. Both too little and too much estradiol can impair erections and drive. It’s particularly important to monitor estradiol if you’re on testosterone therapy, as elevated aromatase activity can push levels too high.
How does hematocrit affect erectile dysfunction?
Hematocrit measures blood thickness. When testosterone stimulates excessive red blood cell production — which can happen on TRT — blood becomes thicker, increasing pressure and reducing the quality of circulation to the penile tissue. This can worsen erections even when testosterone levels are well-optimised. Routine monitoring helps prevent this and supports the vascular function that healthy erections rely on.
Should I have a PSA test even if I have no prostate symptoms?
Yes. Doctors widely recommend PSA screening from age 55 (or earlier with a family history) as a baseline for prostate health monitoring. The goal isn’t to find a “low” number — it’s to establish your personal baseline so that any future rise can be detected early and investigated appropriately. This is particularly important if you’re considering testosterone optimisation, as testosterone can stimulate prostate tissue.
Can these blood markers be improved without medication?
In many cases, yes — at least partially. Lifestyle factors including resistance training, quality sleep, reducing alcohol intake, managing body fat, and reducing chronic stress all have meaningful impacts on testosterone, estradiol balance, and hematocrit. However, significant hormonal imbalances typically require clinical guidance. Shockwave therapy can also support the vascular side of the equation by improving blood flow to erectile tissue, complementing hormonal optimisation without replacing it.
Take the Next Step Toward Real Answers
If you’re approaching or past 55 and still relying on a single testosterone number to gauge your hormonal health, you’re working with incomplete information. Testosterone, estradiol, PSA, and hematocrit together give you — and your doctor — the full picture.
At Shockwave Clinic in Cape Town, the team treats blood work as a foundation, not an afterthought. Whether you’re exploring non-invasive ED treatment, considering the role of hormones in your recovery, or simply want to understand what’s driving your symptoms, the right markers make the difference between chasing numbers and actually solving the problem.
Book a private consultation to discuss what your blood panel should include — and what the results mean for your treatment options.
