Low Testosterone or Depression? How to Tell - And What to Do Next

Low mood and libido plus fatigue could be depression or a serious hormone issue.

What the Numbers Say

• Men’s average testosterone declines about ~1% per year after age 30.  

• Obstructive sleep apnea strongly correlates with lower testosterone; treating apnea can help restore levels. 

• SSRIs/SNRIs like Prozac, Lexapro, Cymbalta used to treat depression frequently cause sexual dysfunction—commonly ~40–70% across studies. 

• The TRAVERSE trial (NEJM 2023) found TRT - Testosterone Replacement Therapy - did not cause an increase in adverse cardiovascular events in men with low testosterone and at high cardiovascular risk.  

• In the U.S., men’s suicide rate is ~4× women’s - so “I’m tired” can be code for “I’m not okay.”  

These numbers explain why men may be misdiagnosed and not treated appropriately.

Why Low Testosterone (Hypogonadism) Gets Missed

The challenge is that men with low testosterone may have similar symptoms to depression:

• Low mood

• Loss of motivation

• Low energy

 In addition, clinicians may neglect to ask about the three most common testosterone-sensitive symptoms:

• Sex drive

• Erection quality (especially morning erections)

• Ability to enjoy sex or feel aroused

Loss of morning/nocturnal erections is particularly suggestive of hypogonadism. NCBI+1

What Testosterone Actually Does

Testosterone influences:

• Motivation and reward

• Sleep quality

• Muscle–fat balance

• Energy and focus

• Sexual desire and erections

Levels decline gradually with age, but sleep apnea, obesity, chronic stress, opioids, glucocorticoids, and head injury can accelerate the drop. PMC+1

Depression vs. Low Testosterone: Side-by-Side

Symptom	Often in Depression	Often in Low T
Irritability or low mood	Yes	Yes
Loss of motivation or drive	Yes	Yes
Fatigue or low energy	Yes	Yes
Low libido or erectile issues	Sometimes	Common
Loss of morning erections	Rare	Very specific
Muscle loss or fat gain	Occasionally	Common
Guilt or hopelessness	Frequent	Uncommon
Suicidal thoughts	Possible	Rare

The most specific signal of low testosterone is the sexual symptom triad: low libido, weaker erections, and loss of morning erections. Fatigue and low mood alone aren’t enough. NCBI+1

When to Get Tested

Ask for labs if you’ve had weeks to months of:

• No morning erections

• Reduced libido or weaker erections

• Unexplained fat gain or muscle loss

• Exhaustion despite adequate sleep

• Known risks (sleep apnea, heavy alcohol use, opioids/steroids)

• Past testicular injury or concussion

These patterns warrant a thorough workup. 

How to Test the Right Way

Don’t rely on a single number. Use this protocol:

• Two early-morning total testosterone levels (7–10 a.m.)

• Repeat, 7–14 days apart

• Be well-rested and not acutely ill

If total Testosterone is borderline (~300–350 ng/dL), add:

• Free testosterone, SHBG

• LH, FSH, prolactin, TSH/thyroid

Diagnosis requires both symptoms and two low morning total testosterone values; symptoms or one low value alone aren’t enough. (The AUA uses <300 ng/dL as a diagnostic cut-off.) 

What TRT Can—and Can’t—Do

Testosterone Replacement Therapy (TRT) helps when testosterone is truly low and contributors (sleep apnea, alcohol, sedatives/SSRIs) are addressed. Expect benefits in sexual symptoms and energy. It’s not a shortcut to confidence or a cure for grief, trauma, or isolation. Endocrine Society

Safety and Fertility

When properly diagnosed and monitored, TRT appears heart-safe for most men, like those in TRAVERSE; the FDA updated the labels in 2025 to reflect the trial data (and added a blood-pressure warning on some formulations). Monitor:

• Hematocrit

• Serum testosterone 

• PSA 

• Blood pressure

  
  

  TRT can suppress sperm; discuss hCG or clomiphene/enclomiphene to raise testosterone while preserving spermatogenesis. ScienceDirect+4New England Journal of Medicine+4PubMed+4

The 3–6 Month Stop Rule

If sexual function, vitality, or quality of life hasn’t meaningfully improved after 3–6 months of well-run TRT (correct dose, adherence, comorbidity control), pause and reassess. Don’t stay on hormones indefinitely if they’re not helping. (This aligns with guideline-based, outcome-oriented practice.) Endocrine Society

SSRIs, Sexual Side Effects, and Timing

Antidepressants - especially SSRIs/SNRIs - often reduce libido, arousal, and orgasm and may slightly lower testosterone in some contexts. If sexual symptoms began after starting an antidepressant, consider:

• Dose timing

• Switching to a lower-risk agent (Bupropion/Wellbutrin, Vilazodone/Viibryd)

• Adjuncts (e.g., Bupropion; PDE5 inhibitors for ED like Viagra or Cialis)  

A Clear Path Forward

1) Ask the Right Questions

Have libido, erections, and morning erections changed? When did symptoms start - relative to meds, sleep, weight, or stress?

2) Test Properly

Two early-morning total testosterone levels from the same lab; add free T/SHBG/LH/FSH if borderline.

3) Fix What’s Fixable

Treat sleep apnea; reduce alcohol; review meds (SSRIs/SNRIs); strength-train twice weekly; sleep 7–8 hours.  

4) Treat Based on Data

• Low T + symptoms → Consider TRT with monitoring.  

• Normal T + depression signs → Treat depression (therapy, meds, lifestyle).

• Mixed picture → Change one variable at a time to see what helps.

Final Thoughts

Low testosterone and depression can look nearly identical - but they require different treatments. Testing early helps avoid misdiagnosis and the wrong treatment. TRT can restore drive and clarity when the biology fits, but it’s not a cure-all.  Asking the right questions, getting appropriate  labs, and doing the work hormones can’t do is key for best outcomes.

If this sounds familiar, ask your clinician for morning total and free testosterone tests - before assuming it’s “just in your head.”  

Further Reading

• TRAVERSE Trial — Cardiovascular Safety of Testosterone (NEJM, 2023). Non-inferior MACE vs placebo in high-risk men on TRT. New England Journal of Medicine

• Endocrine Society Guideline (JCEM, 2018): Diagnosis, indications, and monitoring for TRT. Endocrine Society

• American Urological Association Guideline (updated web resource, accessed 2025): Diagnostic threshold <300 ng/dL and testing protocol. American Urological Association  

• Frontiers Review (2023): OSA, obesity, and hypogonadism inter-relations. Frontiers

• Cureus/Reviews (2022–2024): Antidepressant-related sexual dysfunction prevalence and management strategies. Iji App+1

• CDC/NIMH (2024): Male–female suicide rate gap and implications for screening. CDC+1

Authorship

Frederic Kass, MD — Professor Emeritus of Psychiatry, Columbia University Medical Center; former Clinical Vice Chair, Department of Psychiatry Profile: Medical News Today

Erica Gettenberg, MD — Board-Certified in Adult, Child, and Adolescent Psychiatry; expertise in mood and anxiety disorders and ADHD. LinkedIn: Erica Gettenberg, MD

All vignettes are fictional and for educational purposes only. This is not a substitute for professional medical advice.