Do Men with Diabetes Have Healthy Sperm? Doctors Explain the Link Between Blood Sugar and Fertility

Diabetes is a widespread condition affecting millions worldwide. For men, diabetes doesn’t just impact blood sugar levels; it also plays a significant role in sexual health and fertility. High blood sugar is known to harm the heart, kidneys, eyes, and nerves, but the connection between diabetes and fertility often goes unnoticed. Many men deal with issues like low libido, erectile dysfunction, or changes in sperm quality without realising their blood sugar may be playing a role. So, can men with diabetes have healthy sperm? And what should couples who are trying to conceive know?

To understand this better, we spoke to two experts, Dr Shyam Varma, Consultant, Urologist and Renal Transplant Surgeon, Kokilaben Dhirubhai Ambani Hospital, Mumbai, and Dr Rashi Agrawal, Consultant, Endocrinology, Kokilaben Dhirubhai Ambani Hospital, Navi Mumbai. They explain what the science says and what men should do.

How Does Diabetes Affect Sperm Health?

Dr Shyam Varma explains, “Uncontrolled diabetes often damages sperm health. High blood sugar is a silent stressor that causes damage to sperm DNA, making its genetic blueprint faulty.” This damage can reduce sperm count and impair motility, meaning sperm move slowly or weakly. He further adds, “Diabetes can lower testosterone levels, cause erectile dysfunction, or retrograde ejaculation, all of which affect fertility.”

Dr Rashi Agrawal points out that chronic high blood sugar increases oxidative stress, damaging sperm DNA and reducing sperm quality. She states, “Insulin resistance common in type 2 diabetes disrupts the hormones controlling sperm production, resulting in lower testosterone levels and reduced libido.”

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What Happens to Sperm Quality and Hormones?

High blood sugar causes oxidative stress, which breaks DNA strands inside sperm, leading to:

• Low sperm count
• Poor motility (slow movement)
• Abnormal morphology (shape defects)
• Higher DNA fragmentation
• Besides sperm quality, hyperglycemia affects the epididymis, the tube where sperm mature, compromising their fertilising ability.
• Insulin resistance worsens this by causing hormonal imbalances:
• Lower testosterone
• Higher estrogen
• Altered luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which control sperm production

Men with diabetes often experience increased erectile dysfunction, reduced libido, and higher scrotal temperature due to obesity, all of which reduce fertility.

Differences Between Type 1 and Type 2 Diabetes Effects on Fertility

Dr Varma explains that both types affect fertility but through different mechanisms:

• Type 1 Diabetes: Mainly autoimmune with long-term high blood sugars, oxidative stress, nerve damage affecting ejaculation, and altered hormones.
• Type 2 Diabetes: Strongly linked to obesity and metabolic syndrome with more pronounced effects on testosterone, sperm quality, and erectile function.

Both can reduce sperm parameters and cause sexual dysfunction if blood sugar control is poor.

Diabetes and Erectile Dysfunction or Low Testosterone

Erectile dysfunction (ED) is common in diabetic men. “Damaged blood vessels and nerves reduce the ability to have or maintain erections,” Dr Varma says. Men with diabetes have 3 to 5 times higher ED risk.

Low testosterone results from poor glycemic control, suppressing hormone functions, leading to decreased libido, fatigue, and impaired sperm production.

Are Diabetes Medications Safe for Men Trying to Conceive?

Dr Agrawal reassures, “Most diabetes medications are safe and do not harm fertility.” For example:

• Metformin may actually improve sperm quality by reducing insulin resistance.
• Insulin therapy is safe.
• SGLT2 inhibitors and GLP-1 agonists show no evidence of harm to male fertility.
• Pioglitazone may lower testosterone—use with caution.
• Always consult a doctor before stopping or changing any medication.

How to Assess Male Fertility with Diabetes

According to the experts, the assessment includes several tests:

• Semen analysis: counts, motility, shape, DNA fragmentation
• Hormonal profile: testosterone, LH, FSH, prolactin, SHBG
• Blood sugar tests: HbA1c and fasting glucose
• Scrotal ultrasound: detect varicocele or testicular issues
• Penile Doppler: if ED is suspected

Preventive Measures to Support Fertility

Good diabetes management can improve fertility prospects. Important steps include:

• Maintaining HbA1c below 7%
• Regular exercise
• Reducing abdominal fat
• Balanced, low-glycemic diet
• Avoid smoking and excess alcohol
• Early treatment of ED
• Correcting low testosterone if medically indicated
• Adequate sleep and stress management
• Taking antioxidants like Vitamins C, E, zinc, and CoQ10 if advised
• Regular follow-ups with diabetologists and urologists

A study published in BioMed Research International found that diabetes damages sperm motility, DNA integrity, and hormone balance, all crucial for fertility. It highlighted that diabetic men show poor sperm function, but aggressive glycemic control can help improve outcomes.

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Conclusion

Diabetes does not automatically mean infertility, but uncontrolled blood sugar can affect sperm quality, hormones, and sexual health. The good news is that most of these effects improve with proper diabetes management, lifestyle changes, and timely medical care. With expert guidance and consistent control of blood sugar, many men with diabetes are able to conceive without difficulty.