This informational guide, part of POPSUGAR's Condition Center [1], lays out the realities of this health concern: what it is, what it can look like, and strategies that medical experts say are proven to help. You should always consult your doctor regarding matters pertaining to your health and before starting any course of medical treatment.

Editor's Note: We at POPSUGAR recognize that people of many genders and identities have a cervix, not just those who are women. For this particular story, we interviewed sources who generally referred to people with cervixes as women.

Hashimoto's disease is an autoimmune condition that impacts the thyroid gland, and it's more common than you might think. It affects more than 14 million people [2] in the US, and most of them are women and those assigned female at birth (AFAB). In fact, "women are four times more likely than men [3]" to have Hashimoto's, says Stephanie Smooke Praw [4], MD, a clinical endocrinologist and associate professor at the UCLA David Geffen School of Medicine. But some research suggests [5] that women could be up to 10 times more likely to test positive for Hashimoto's.

While Hashimoto's has been in the spotlight more and more recently, thanks to celebrities like Gigi Hadid [6] coming forward with their diagnoses, you may not know that the disease itself doesn't cause symptoms. But Hashimoto's can lead to hypothyroidism, which does come with serious symptoms, ranging from fatigue and weakness to menstrual irregularities and cognitive dysfunction. So what is Hashimoto's, how does it relate to hypothyroidism, and is there anything you can do to treat it? Here, POPSUGAR spoke to two experts for everything you should know about this common but confusing condition.

Understanding Hashimoto's Disease

Hashimoto's disease, also known as Hashimoto's thyroiditis, is an autoimmune condition characterized by the presence of antibodies that target the thyroid gland, a butterfly-shaped gland at the base of the neck that produces hormones. "Typically, our body creates antibodies to fight external elements like viruses," explains Caroline Nguyen [7], MD, board-certified endocrinologist and assistant professor of clinical medicine at the Keck School of Medicine of USC. "But in autoimmune conditions, your immune system has created an antibody that is now attacking the body itself." Hashimoto's, she explains, occurs when there are antibodies that attack the thyroid gland specifically. These are known as thyroid peroxidase antibodies, or TPO antibodies.

These antibodies can increase production of thyroid-stimulating hormone (TSH), which is produced in the pituitary gland and is meant to trigger your thyroid to release hormones. Thyroid hormones tend to rise with high levels of TSH, and drop with low levels of TSH. "When thyroid hormones are low, they act as feedback to tell the body to release more TSH. So higher than normal TSH levels can mean your body isn't making enough thyroid hormone," explains Micaela Bayard, MD, [8] board-certified rheumatologist, assistant professor of medicine at the Icahn School of Medicine at Mount Sinai, and advisory board member for POPSUGAR's condition center.

Not making enough thyroid hormones, can also be indicative of hypothyroidism, a disease that affects about five percent of adults in the US, according to NIDDK [9]. While hypothyroidism comes with a host of possible symptoms (see ahead), Hashimoto's disease itself — which is when you have that TPO antibody — does not. "It's not the antibody that causes symptoms," Dr. Smooke Praw explains. "What causes symptoms is when the antibody has impacted the thyroid and the thyroid starts to not function," aka hypothyroidism. "A person can have Hashimoto's disease, which means the presence of those antibodies, but they could still have normal thyroid function," Dr. Nguyen adds. "But [Hashimoto's] does put you at risk over time for developing thyroid dysfunction."

For that reason, Hashimoto's can't be diagnosed by symptoms alone — because it has no noticeable symptoms. Instead, patients are diagnosed via a blood test. Sometimes this happens somewhat retroactively, after the Hashimoto's has already progressed to hypothyroidism. Because of this, it can be helpful to recognize the effects symptoms of hypothyroidism, including:

• Fatigue and increased sleepiness
• Increased sensitivity to cold
• Dry skin and brittle hair or nails
• Constipation
• Muscle weakness, aches, tenderness, and stiffness
• Joint pain and stiffness
• Weight gain
• Cognitive dysfunction, including issues with memory or concentration
• Thyroid swelling (also known as a goiter)
• Depression
• Menstrual irregularities, such as irregular or excessive bleeding
• Puffy face
• Tongue swelling

In more severe cases of hypothyroidism, symptoms may include shortness of breath, low heart rate, and hypothermia. And low levels of thyroid hormone can even impair fertility, per Mayo Clinic [10].

Many of the main symptoms of hypothyroidism can also overlap with other conditions, Dr. Nguyen notes. It's worth a talk with your doctor if you're experiencing the symptoms above to rule out other health conditions and get the proper treatment, she adds.

Causes and Risk Factors For Hashimoto's Disease

Hashimoto's occurs when antibodies from your immune system attack thyroid cells, mistaking them for threatening foreign bodies. Experts don't fully know what causes these autoantibodies to develop, but Mayo Clinic lists several risk factors [11] that may increase your chances of having Hashimoto's including:

• Being a woman: Women are four to 10 times more likely to get Hashimoto's disease, presumably due to the fact that the disease is linked to autoimmunity and autoimmune disease, which is occur more frequently in women [12].
• Age: Hashimoto's often occurs in middle age.
• Preexisting autoimmune disease: If you already have an autoimmune condition, such as rheumatoid arthritis, type 1 diabetes, or lupus, your risk of developing Hashimoto's is higher.
• Genetics: Hypothyroidism and Hashimoto's can both run in families, Dr. Smooke Praw explains, but "it's not a guarantee," Dr. Nguyen adds. "Just because the parent has [Hashimoto's], doesn't mean that the child's going to have it."
• Pregnancy: Your immune system changes during pregnancy, which can be a trigger for Hashimoto's developing after pregnancy.
• Excessive iodine intake: People who consume too much iodine can actually trigger the onset of the disease, especially for those already at risk of the condition.
• Radiation exposure: You may be at increased risk of Hashimoto's disease if you've been exposed to high levels of environmental radiation.

The connection between Hashimoto's and pregnancy is important to be aware of. If you have Hashimoto's and you get pregnant, your thyroid may not be able to produce the increased amounts of hormones needed during this time, Dr. Nguyen explains. That may put you at risk for having thyroid dysfunction during pregnancy and during the postpartum period (known as postpartum thyroiditis). Postpartum thyroiditis in particular "can lead to swings in your thyroid levels," Dr. Nguyen says, causing symptoms of hypothyroidism and/or hyperthyroidism, which is the opposite of hypothyroidism, and is characterized by having low TSH levels.

The Most Effective Treatments For Hashimoto's Disease

There are no direct treatments for Hashimoto's. If a patient only has Hashimoto's that hasn't progressed to hypothyroidism — in other words, if they have the Hashimoto's antibody, but not the excessively high levels of TSH that would indicate a thyroid issue — they won't experience symptoms and no treatment is needed. "You can have this antibody your entire life and it may never impact the thyroid," Dr. Smooke Praw explains.

If you have Hashimoto's, the recommended course of action is to monitor your thyroid function through annual checkups and thyroid tests with your doctor. If your doctor detects abnormally high levels of TSH and indications of hypothyroidism, they'll typically prescribe you a thyroid hormone replacement drug, such as Levothyroxine, as a first-line treatment option.

Doctors do not currently recommend taking specific supplements or changing your eating habits to manage Hashimoto's, according to the NIDKK [13], although research is ongoing in this area. "We don't have the data to show that certain dietary changes can change your prognosis," Dr. Nguyen explains. The exception is iodine; NIDKK notes that taking iodine supplements or eating foods with large amounts of iodine, such as kelp, dulse, and other kinds of seaweed [14], "may cause hypothyroidism or make it worse." If you have Hashimoto's or other thyroid conditions, talk to your doctor about what level of iodine is healthy for you.

In general, doctors recommend taking the "wait and see" approach with Hashimoto's, meaning that you and your doctor should monitor the condition regularly and start treatments for hypothyroidism only if and when they're necessary. If you do start experiencing symptoms of hypothyroidism, talk to your doctor about checking your thyroid function.