Verbatim response from Perplexity
Yes — low testosterone could be one possible cause of being tired, having low motivation, and having low libido, because those are recognized symptoms of testosterone deficiency.[1][2][5][8]
That said, these symptoms are not specific to low testosterone. Cleveland Clinic and UCSF both note that fatigue, mood changes, poor concentration, and low libido can occur with low T, but the symptoms are general and other causes may be responsible even when testosterone is low.[1][8] Common alternatives include poor sleep or obstructive sleep apnea, obesity, chronic illness, depression, thyroid problems, medication side effects, and diabetes.[2][4][5]
What typically confirms low testosterone is a blood test, usually two morning total testosterone measurements, because levels fluctuate during the day and can be temporarily lowered by illness.[1][2] MedlinePlus and Cleveland Clinic also note that providers may check related hormones such as LH and prolactin to look for the cause.[1][5]
A practical next step is to see a primary care doctor, endocrinologist, or urologist for evaluation, especially if the low libido and low energy are persistent.[6][8] If you also have erectile dysfunction, fewer morning erections, decreased muscle mass, loss of body hair, enlarged breasts, or infertility, low T becomes more likely.[1][5][8]
If you want, I can help you make a short symptom checklist to take to your doctor and suggest what labs are usually ordered.