TL;DR — Key Takeaways

• Yes, low testosterone can cause anemia.
• Testosterone drives red blood cell production, so low T can lower red-cell counts.
• It’s a recognized cause of “unexplained” anemia, especially in older men.
• The NIH Testosterone Trials showed testosterone treatment corrected anemia in men with low T.
• The exact mechanism isn’t fully understood, but the link is well established and treatable.

Yes, low testosterone can cause anemia. Testosterone drives red blood cell production, so when it’s low, red-cell counts can fall, causing anemia, often the “unexplained” kind in older men. The NIH Testosterone Trials showed testosterone treatment can correct anemia in men with low T. The mechanism isn’t fully understood, but the link is well established.

If your bloodwork shows anemia and low testosterone, the two may be connected. Here’s exactly how, backed by the research. (For the full symptom picture, see low testosterone symptoms; for the overview, our complete TRT guide.)

Can Low Testosterone Cause Anemia?

Yes. Testosterone is one of the hormones that stimulates red blood cell production, so low testosterone is a recognized, and often overlooked, cause of anemia (a low red blood cell count or low hemoglobin). It’s especially relevant in older men, where low T is linked to higher rates of “unexplained” anemia. The Endocrine Society lists unexplained anemia among the possible features of testosterone deficiency.

Key fact: Testosterone drives red blood cell production, so low testosterone is a recognized, treatable cause of unexplained anemia in men.

How Does Low Testosterone Cause Anemia?

Testosterone supports erythropoiesis (red blood cell production) through several mechanisms:

• Stimulates erythropoietin (EPO), the hormone that signals red-cell production (though research suggests this effect may be small and transient).
• Increases iron availability by suppressing hepcidin, freeing up iron for new red cells.
• Boosts bone-marrow progenitors and improves red cell survival.

So when testosterone is low, this support weakens and red-cell counts can drift down. Researchers note the exact mechanism is still incompletely understood, but the clinical link is consistent. This is the same red-cell system that runs in reverse on therapy — where TRT can push counts too high (see high hematocrit on TRT and hematocrit vs hemoglobin).

What the Research Shows

The evidence is solid for the connection:

• The NIH Testosterone Trials (Roy et al., JAMA Internal Medicine, 2017) found testosterone treatment corrected anemia in older men with both unexplained and iron-deficiency anemia, versus placebo.
• Testosterone therapy has shown hemoglobin-raising effects comparable to erythropoietin-stimulating agents in hypogonadal men.
• Caveat: there’s no large trial with anemia as the primary outcome, so it’s an associated/secondary benefit, not an approved anemia drug.

What Type of Anemia Does Low Testosterone Cause?

Typically a mild, normocytic anemia (normal-sized red cells, just fewer of them), the kind that often shows up as “unexplained anemia” when other causes (bleeding, B12, etc.) are ruled out. That’s why, in older men with unexplained anemia, checking testosterone can uncover a treatable cause. It overlaps with the fatigue and lightheadedness covered in does low testosterone cause dizziness — anemia is often the bridge between low T and those symptoms.

Does Treating Low Testosterone Fix Anemia?

Often, yes. When low testosterone is the cause. Restoring testosterone to a normal range can raise hemoglobin and correct the anemia, as the Testosterone Trials showed. But anemia has many causes, so TRT isn’t an anemia treatment in general, it helps when low T is the underlying driver. That’s why confirming your levels with the right testosterone test (vs normal ranges) and working out whether TRT is right for you matters — alongside a proper anemia workup.

The Bottom Line

Can low testosterone cause anemia? Yes, testosterone drives red blood cell production, and low T is a recognized cause of anemia, especially “unexplained” anemia in older men. Research, including the NIH Testosterone Trials, shows restoring testosterone can correct it when low T is the cause. If you have unexplained anemia, it’s worth checking your testosterone, but get a full anemia workup too, since the causes are many.

👉 If you have anemia and low-T symptoms, find the link, check your testosterone with an at-home test kit and review your full bloodwork with a licensed provider.

Frequently Asked Questions

Can low testosterone cause anemia?

Yes. Testosterone stimulates red blood cell production, so low testosterone can lower red-cell counts and cause anemia, often the “unexplained” type seen in older men. It’s a recognized, treatable cause, and the Endocrine Society lists unexplained anemia among features of testosterone deficiency.

How does low testosterone cause anemia?

Testosterone supports red blood cell production by stimulating erythropoietin, increasing iron availability (by suppressing hepcidin), boosting bone-marrow progenitors, and improving red cell survival. When testosterone is low, this support weakens and red-cell counts can fall, though the exact mechanism is still being studied.

Does TRT fix anemia?

Often, when low testosterone is the cause. The NIH Testosterone Trials showed testosterone treatment corrected anemia in older men with low T. But anemia has many causes, so TRT isn’t a general anemia treatment, it helps specifically when low testosterone is the underlying driver.

What type of anemia does low testosterone cause?

Usually a mild, normocytic anemia, normal-sized red blood cells but fewer of them. It often appears as “unexplained anemia” once other causes like bleeding or B12 deficiency are ruled out, which is when checking testosterone can reveal a treatable cause.

Can testosterone raise hemoglobin?

Yes. Testosterone raises hemoglobin and red blood cell counts, with effects comparable to erythropoietin-stimulating agents in men with low testosterone. This is also why too much testosterone on therapy can push hemoglobin and hematocrit too high, which is monitored on TRT.

Should you check testosterone if you have unexplained anemia?

It’s reasonable, especially for older men. Low testosterone is a recognized cause of unexplained anemia, so testing can uncover a treatable driver. It should be part of a full anemia workup that also rules out bleeding, iron, B12, and other causes.

Written by: TRT NYC Editorial Team, Last updated: June 2026 · Reviewed against: peer-reviewed research, Endocrine Society, and NHLBI guidance (see References).

Medical disclaimer: This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Anemia should be evaluated by a clinician with a full workup. trtnyc.com is an independent informational resource, not a medical provider.