Signs Your Testosterone Is Low: The Complete Symptoms Checklist
Feeling tired all the time? Lost interest in sex? Can't build muscle like you used to? These could be signs of low testosterone. Here's how to recognize the symptoms—and when to get tested.
The Numbers
40%
of men 45+ have low T
1%
decline per year after 30
<300
ng/dL is considered low
Primary Symptoms (Most Directly Linked to Low T)
These symptoms are the strongest indicators that low testosterone may be the cause:
🔻 Decreased Sex Drive
A significant drop in desire for sex—not just occasional disinterest, but a noticeable, sustained decline from your normal baseline. This is often the first symptom men notice.
🔻 Erectile Dysfunction
Difficulty achieving or maintaining erections, including fewer spontaneous erections (like morning erections). Note: About 35% of men with ED have low testosterone.
🔻 Reduced Testicular Size
Smaller-than-normal testicles. The testicles produce testosterone, and low T can cause them to shrink.
🔻 Loss of Morning Erections
Nocturnal and morning erections are driven by testosterone. If you used to wake up with erections and no longer do, this is significant.
🔻 Hot Flashes
Yes, men can get hot flashes. Sudden feelings of warmth, sweating, and flushing—similar to what women experience in menopause—can indicate very low T.
Secondary Symptoms (May Be Related to Low T)
These symptoms can be caused by low testosterone but also have other potential causes:
⚡ Fatigue & Low Energy
Persistent tiredness despite adequate sleep. Feeling drained, unmotivated, or like you're running on empty.
💪 Muscle Loss
Losing muscle mass even while maintaining your workout routine. Difficulty building new muscle despite training.
🔄 Increased Body Fat
Gaining fat, especially around the belly. Some men develop gynecomastia (enlarged breast tissue).
😔 Mood Changes
Depression, irritability, anxiety, or emotional changes that feel "out of character." Difficulty concentrating.
🦴 Weak Bones
Testosterone helps maintain bone density. Low T over time can lead to osteoporosis and increased fracture risk.
💤 Sleep Problems
Insomnia or disrupted sleep. Note: Sleep apnea can both cause and result from low testosterone.
🧔 Hair Loss
Reduced body, facial, or scalp hair. (Though ironically, too much testosterone-converted-to-DHT also causes hair loss.)
🧠 Brain Fog
Difficulty concentrating, memory problems, or feeling mentally "slow."
Quick Self-Assessment
Check how many apply to you. This isn't diagnostic—only a blood test can confirm low T—but it can help you decide if testing makes sense.
Result: If you checked 3+ of the first five symptoms, or 5+ total, consider getting your testosterone levels tested.
What Causes Low Testosterone?
Low T can result from:
Natural Causes
- • Aging — ~1% decline per year after 30
- • Obesity — 30% of overweight men have low T
- • Type 2 diabetes — 25% prevalence of low T
- • Sleep apnea — directly lowers testosterone
- • Chronic stress — cortisol suppresses T production
Medical Causes
- • Testicular injury or cancer
- • Pituitary gland problems
- • Chemotherapy/radiation
- • Certain medications (opioids, steroids)
- • Genetic conditions (Klinefelter syndrome)
How Is Low Testosterone Diagnosed?
A blood test is the only way to confirm low testosterone. Here's what to know:
The Testing Process
- 1. Blood draw in the morning — T levels are highest before 10am
- 2. Two tests required — one abnormal result isn't enough for diagnosis
- 3. Normal range: 300-1000 ng/dL (most labs)
- 4. Low T threshold: Below 300 ng/dL
- 5. Additional tests: LH, FSH, prolactin may be checked to find the cause
💡 Important Context
Some men have symptoms even with testosterone in the "normal" range. The optimal level varies by individual. Many experts suggest 400-600 ng/dL is the healthiest range for most men. Symptoms + blood work together guide treatment decisions.
Get Your Testosterone Tested
At-home testing kits or online clinic consultations. Results in days.
When Should You See a Doctor?
Consider getting tested if:
- •You have multiple symptoms from the list above
- •Symptoms are affecting your quality of life or relationships
- •You're over 40 and noticing changes
- •You have diabetes, obesity, or other risk factors
- •You have ED that doesn't respond to ED medications
Don't self-diagnose or try to treat with supplements. Low T symptoms overlap with many other conditions (thyroid problems, depression, diabetes). A proper diagnosis ensures you get the right treatment.
Treatment Options for Low Testosterone
If testing confirms low T, treatment options include:
Testosterone Replacement Therapy (TRT)
- • Injections: Weekly or bi-weekly (most common)
- • Gels/creams: Applied daily to skin
- • Patches: Applied daily
- • Pellets: Implanted every 3-6 months
- • Oral: Newer options available
TRT can improve energy, libido, muscle mass, mood, and bone density. However, it has risks (increased red blood cells, potential heart effects, fertility suppression) and requires ongoing monitoring.
Key Takeaways
- 1. Primary symptoms: Low libido, ED, loss of morning erections, reduced testicle size
- 2. Secondary symptoms: Fatigue, muscle loss, mood changes, weight gain, brain fog
- 3. Testing is essential: Only a blood test can confirm low T
- 4. Normal range: 300-1000 ng/dL; below 300 is considered low
- 5. Common causes: Aging, obesity, diabetes, sleep apnea, certain medications
- 6. Treatment exists: TRT can help if you're truly low
- 7. Don't guess: Get tested before trying testosterone boosters or TRT
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. The symptom checklist is not a diagnostic tool. Low testosterone can only be diagnosed through blood testing by a qualified healthcare provider. Many conditions share symptoms with low T. Consult a doctor before starting any treatment.