Yes, men can and do get Hashimoto’s thyroiditis. While it’s far more common in women, about 6% of adult men have the condition, and men make up roughly 27% of all Hashimoto’s cases. The perception that it’s a “women’s disease” often leads to delayed diagnosis in men, sometimes by years.
How Common Is Hashimoto’s in Men?
A large meta-analysis of global data found that Hashimoto’s affects about 6% of adult men, compared to 17.5% of adult women. That puts the female-to-male ratio at roughly 4 to 1. A separate study of over 92,000 Hashimoto’s patients confirmed a similar breakdown: 73% female, 27% male. So while women are disproportionately affected, men are far from immune. Prevalence in men ranges from about 1% to 8% depending on geographic region and socioeconomic factors.
These numbers also mean Hashimoto’s is not rare in men by any reasonable standard. For perspective, 6% is comparable to the prevalence of type 2 diabetes in many countries. The “women’s disease” label can give men, and sometimes their doctors, a false sense of security.
Why Men Get Diagnosed Later
One of the biggest problems men face with Hashimoto’s is delayed diagnosis. The symptoms are notoriously nonspecific: fatigue, weight gain, feeling cold, hair thinning, brain fog, and constipation. In one study, 20% of hypothyroid patients experienced a significant diagnostic delay simply because their doctors didn’t suspect a thyroid problem given how vague the symptoms were. Tiredness showed up in 79% of cases, weight gain in 67%, and hair loss in 46%.
For men, there’s an added layer. Because Hashimoto’s is so strongly associated with women, many men don’t think to mention thyroid-related symptoms, and some clinicians don’t think to test for them. A man showing up with fatigue, low mood, and weight gain might get screened for depression or low testosterone before anyone checks his thyroid. That means the underlying autoimmune process can quietly damage the thyroid for months or years before it’s caught.
Symptoms That Affect Men Specifically
Men with Hashimoto’s experience all the classic hypothyroid symptoms, but a few deserve special attention because they’re often attributed to other causes in men.
Erectile dysfunction is one of the most significant. Studies show that up to 52% of men with overt hypothyroidism experience ED. Even subclinical hypothyroidism, where thyroid levels are only mildly off, is linked to worse erectile function compared to men with normal thyroid levels. The mechanism involves both direct hormonal effects and elevated prolactin, a hormone that rises when the thyroid is underactive. High prolactin suppresses libido and contributes to ED. Because ED is so commonly blamed on stress, aging, or cardiovascular issues, the thyroid connection often goes unexplored. Screening for thyroid dysfunction in men presenting with ED is now recommended by researchers in the field.
Muscle weakness and reduced exercise tolerance also hit men hard, partly because hypothyroidism slows metabolism and impairs muscle recovery. Men who are physically active may notice declining performance or an inability to maintain muscle mass despite consistent training.
Effects on Male Fertility
Hashimoto’s can directly impair male fertility in several ways. Hypothyroidism reduces semen volume and progressive sperm motility, meaning sperm are fewer and move less effectively. Studies also show abnormal sperm shape in hypothyroid men. These changes happen because thyroid hormones play a role in the maturation of the cells that produce sperm. When thyroid function drops, the signaling hormones that stimulate sperm production (LH and FSH) also decline, leading to less mature sperm cells in the testes.
In prolonged or severe cases, testosterone levels can drop as well, compounding the fertility problem. Some men with untreated hypothyroidism develop enlarged testes, which sounds counterintuitive but reflects an increase in immature cells rather than healthy, functioning tissue. The good news is that these fertility effects are largely reversible once thyroid hormone levels are restored to normal.
What Causes Hashimoto’s in Men
Hashimoto’s results from a combination of genetic susceptibility and environmental triggers. Several gene families are involved, including the HLA complex, which helps the immune system distinguish the body’s own tissue from foreign invaders. When these genes carry certain variations, the immune system is more likely to mistakenly attack the thyroid gland.
Environmental triggers can activate the disease in genetically predisposed people. These include viral infections, excess iodine intake, exposure to ionizing radiation, and certain medications. The fact that women are affected more often is thought to relate at least partly to sex hormones, particularly estrogen, which influences immune function. But men with the right genetic background and environmental exposures are fully capable of developing the same autoimmune response.
Family history is a strong predictor. A large genealogical study found that having a close relative with Hashimoto’s significantly increases your own risk, regardless of sex. If autoimmune thyroid disease runs in your family, it’s worth paying attention to thyroid symptoms even as a man.
How Hashimoto’s Is Diagnosed
The diagnostic process is identical for men and women. It typically starts with a blood test measuring TSH (thyroid-stimulating hormone). When the thyroid is underperforming, your brain produces more TSH to try to compensate, so a high TSH level is the first red flag. From there, doctors check levels of the actual thyroid hormones T4 and T3, and test for TPO antibodies, which are present in most people with Hashimoto’s.
TPO antibodies are the key distinction between Hashimoto’s and other causes of hypothyroidism. They confirm that the immune system is attacking the thyroid. In some cases where antibodies don’t show up on a blood test, an ultrasound of the thyroid can reveal characteristic patterns of damage or enlargement. Ultrasound also helps rule out thyroid nodules or other structural issues.
There are no different TSH thresholds or diagnostic criteria for men. The same tests apply, and the same reference ranges are used.
Treatment and What to Expect
When Hashimoto’s progresses to hypothyroidism, treatment involves taking a daily synthetic thyroid hormone pill to replace what the thyroid can no longer produce on its own. The goal is to bring TSH levels back into the normal range of 0.4 to 4 mIU/L, which resolves symptoms for most people. Keeping TSH within this range is important: levels that drift too high or too low are associated with increased risk of heart disease, stroke, bone fractures, and premature death.
One notable difference for men is dosing. The amount of thyroid hormone you need is driven primarily by lean body mass, not total body weight. Because men generally carry more muscle than women, they often require higher doses. Research has shown a much stronger correlation between lean mass and the right dose (r = 0.667) than between fat mass and dose (r = 0.26). This means two men at the same weight could need very different doses if one is muscular and the other carries more body fat. Estimating lean mass early on can help your doctor find the right dose faster, especially if you have a high BMI.
Most men notice improvements in energy, mood, and weight within a few weeks of starting treatment, though it can take several months to fully optimize the dose. Sexual function and fertility typically improve as thyroid levels normalize, though recovery timelines vary. Regular blood work, usually every 6 to 12 months once stable, ensures the dose stays appropriate as your body and the disease evolve over time.