Medically reviewed by Anand Thakkar, MD, MSCP. Last updated: September 29, 2026.
Low testosterone and erectile dysfunction often show up together. But the link is not as simple as “low T causes ED.” Testosterone mainly drives desire. Blood flow, nerves and other hormones also shape erections.
If you’re weighing a PRP penile injection, often called the P-Shot or Priapus Shot, see our P Shot Chicago page.
In This Article
How Hormones Affect Erections
An erection starts with desire in the brain, then relies on nerves and blood vessels. Hormones play a part at each step:
- Desire: mainly testosterone, with a role for estrogen
- Energy and mood: thyroid, cortisol and testosterone
- Blood vessel health: insulin and other metabolic hormones, plus thyroid
Low Testosterone and Erectile Dysfunction: Mostly About Desire
Low testosterone often causes low sex drive, fewer morning erections and fatigue. See low testosterone symptoms.
- TRAVERSE study: In 1,161 men with low testosterone and low libido, testosterone gel improved desire and sexual activity. It did not improve erectile function compared with placebo.1
- The Testosterone Trials: In older men with low testosterone, treatment led to modest gains in erectile function.2
What this means: Treating truly low testosterone may improve desire. It is often not enough on its own when blood vessel changes are the main cause.
Low T, Blood Flow or Both? Common Patterns
Low testosterone and erectile dysfunction often overlap. This table shows patterns we look for. It’s a guide for your visit, not a diagnosis.
| What you notice | More likely factor | Tests that help |
|---|---|---|
| Low desire, fatigue, fewer morning erections | Low testosterone | Two morning testosterone tests, LH, FSH |
| Strong desire, but erections fade or won’t hold | Blood flow or venous leak | Heart and metabolic labs; ultrasound when needed |
| ED only with a partner, normal morning erections | Stress or performance anxiety | Medical review, mental health support |
| Low desire plus weight gain, poor sleep, snoring | Low testosterone linked to weight or sleep apnea | Testosterone, A1c, sleep study |
| Gradual ED with diabetes, smoking or high blood pressure | Blood vessel changes | A1c, lipids, blood pressure, heart risk review |
Many men have more than one factor, which is why we test hormones and blood flow together. The Endocrine Society guideline also calls for repeat morning testing before diagnosing low testosterone.
Thyroid, Cortisol and Estrogen
- Thyroid. Both an underactive and an overactive thyroid are linked to ED. In one study, ED often improved once thyroid levels returned to normal.3
- Cortisol. Chronic stress and poor sleep can lower desire and make erections harder to keep.
- Estrogen. Men need some estradiol for desire and erectile function.4 Too much can also cause problems.
- DHEA and growth hormone. Evidence for these as ED treatments is limited.
Why Bliss MD
- Board-certified internist since 2011, plus A4M/ABAARM board certified
- Full hormone testing and ED care beyond hormones
- Clinics in Lincoln Park and our Schaumburg-area clinic in Hanover Park
What a Full Hormone Evaluation Includes
The Endocrine Society recommends confirming low testosterone with at least two early-morning blood tests.5 Our panel may include:
- Total and free testosterone, SHBG, LH, FSH and estradiol
- Thyroid, cortisol, DHEA-S and IGF-1
- A1c, lipids, blood count and PSA
Want to know if hormones are part of your ED?
Treatment: Hormones Plus a Wider Plan
Before you start testosterone: testosterone therapy can lower sperm production, sometimes to zero. If you may want children, tell us first, because other treatments may suit you better. Testosterone also needs regular checks of hematocrit and PSA, per the Endocrine Society.5
When blood flow or tissue changes are also involved, we may add treatments our Priapus Shot Chicago patients often ask about:- PRP (a men’s P Shot). Platelet rich plasma (PRP) comes from your own blood. We apply numbing cream, then inject with ultrasound. It typically costs $1,000 to $2,500 per treatment. See P Shot benefits and P Shot cost.
- Other options. See regenerative ED treatment, P-Shot vs shockwave vs ED medication and PT-141.
- Lifestyle. Weight loss, less alcohol and better sleep support hormones and blood flow.
Your First Men's Health Visit at Bliss MD
Here’s what to expect when you come in for low testosterone or ED:
- Discovery call. A free 15-minute call to decide if a visit makes sense.
- Labs. We draw labs at both clinics any time during clinic hours. Testosterone is highest early, so morning draws are preferred when possible, as the Endocrine Society explains.
- Physician visit. Dr. Thakkar reviews your labs, heart health, medications, sleep, alcohol and stress.
- Your plan. That may include hormones, ED medication, PRP or lifestyle changes, often in combination.
We see men at our Lincoln Park clinic on Halsted and our Schaumburg-area clinic in Hanover Park.
Frequently Asked Questions About Low Testosterone and Erectile Dysfunction
Can low testosterone cause ED?
It can add to it, mostly by lowering desire. Blood vessel health is often the bigger factor.
Do I need a morning blood test?
Yes. Testosterone is highest in the morning, and one low result is not enough.
I searched "P Shot near me." Should I check hormones first?
Yes. Whether you searched for a P Shot for men near me or a Priapus Shot near me, a hormone panel shows whether PRP alone makes sense. Our cost guide covers “P Shot cost near me.”
Can thyroid problems cause erectile dysfunction?
Yes. Both underactive and overactive thyroid are linked to ED. In one study, ED often improved once thyroid levels were back to normal.3
Will testosterone therapy fix my ED?
Not always. Testosterone mainly improves desire. If blood flow is the main cause, you may also need ED medication or other treatment.
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References
- Pencina KM, et al. J Clin Endocrinol Metab. 2024. https://pubmed.ncbi.nlm.nih.gov/37589949/
- Snyder PJ, et al. N Engl J Med. 2016. https://pubmed.ncbi.nlm.nih.gov/26886521/
- Krassas GE, et al. J Clin Endocrinol Metab. 2008. https://pubmed.ncbi.nlm.nih.gov/18270255/
- Finkelstein JS, et al. N Engl J Med. 2013. https://pubmed.ncbi.nlm.nih.gov/24024838/
- Bhasin S, et al. Endocrine Society guideline. 2018. https://academic.oup.com/jcem/article/103/5/1715/4939465
For educational purposes only. Please consult a licensed physician before starting or changing hormone or ED treatment.
