NAC for Thyroid Health

N-acetylcysteine (NAC) is a sulfur-based derivative of the amino acid L-cysteine. In the body, it acts as a powerful antioxidant and has been shown to be almost 100% hepatoprotective - in other words, it has the ability to prevent liver damage. 

thyroid health

In the 1970s, NAC was found to be an antidote for Tylenol (acetaminophen) overdoses; and later, in the 1980s, it was discovered that NAC could help prevent toxic reactions to chemotherapy drugs.

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Hashimoto’s & eliminating toxins

People with Hashimoto often have a reduced ability to eliminate toxins and may have an overload or buildup of toxins. 

Toxins can accumulate due to a leaky gut which can lead to the absorption of problematic substances and impair the ability to detoxify. (Studies have shown that anyone with an autoimmune disease, including Hashimoto's, has some level of leaky gut.)Additionally, there are several other factors associated with Hashimoto that can interfere with the liver's ability to properly remove toxins from the body. 

eliminating toxin

These include:

  1. Decreased ability to sweat and remove toxins through the skin
  2. Problems with nutrient absorption
  3. Food sensitivities leading to the accumulation of antibodies 
  4. Change in the MTHFR gene that can impair the body's ability to methylate (an important detoxification process).

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In the body, NAC converts to glutathione, an antioxidant that not only supports liver function but also helps the liver eliminate heavy metals and other toxins. 

NAC supports healthy glutathione levels by providing the body with cysteine, the limiting factor (or factor that prevents the process from accelerating) of glutathione production. By supporting healthy levels of glutathione, NAC in turn supports optimal levels of TSH and thyroid antibodies.

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Oxidative stress 

Oxidative stress occurs when an imbalance occurs and our cells produce too many free radicals, which imbalance oxidants and antioxidants. 

Many factors can trigger or exacerbate oxidative stress, including chronic stress, lack of sleep, a diet high in sugar and processed foods, medication, environmental toxins, and pesticides.

Oxidative stress can also become a major cause of Hashimoto's and other thyroid disorders. 

In fact, the researchers found increased levels of oxidative stress in people with Hashimoto.

lack of sleep

When our thyroid produces thyroid hormones, it creates free radicals at the same time. Without enough glutathione to control oxidative stress, excessive amounts can affect other tissues. 

Therefore, maintaining a minimal oxidative load is a key part of protecting thyroid function. NAC helps reduce this oxidative stress by neutralizing hydrogen peroxide (which can otherwise cause damage to the thyroid gland). 

Studies have also linked oxidative stress to various mood disorders common in people with Hashimoto's disease, including depression and anxiety because it causes nervous system impairment.

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Protection against Oxidative stress

NAC is a precursor to the antioxidant glutathione. Glutathione is the most abundant antioxidant in your body and is therefore sometimes called the primary antioxidant. It plays a role in many functions, including antioxidant defenses, nutrient metabolism, regulation of cellular events (including gene expression and cell proliferation), and immune response. 


Glutathione also serves as a powerful protector against oxidative stress, which may also protect the body against chronic inflammation. (Conversely, chronic inflammation can decrease glutathione levels.)

Depletion of glutathione levels has been linked to higher levels of thyroid antibodies and may contribute to Hashimoto's disease.

As a precursor to glutathione, NAC can help optimize glutathione levels and reduce thyroid antibodies. NAC is an antioxidant in its own right. As a sulfur donor, it helps scavenge free radicals and does double duty by helping to increase glutathione levels by converting it to glutathione in the body. When you are healthy, your body can produce a solid supply of glutathione. 

Unfortunately, many of the variables that overwhelm your body with oxidative stress and chronic inflammation — such as stress, infections, and poor diet — can cause your body to produce less than optimal amounts of this key antioxidant. 

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Chronic inflammation

Chronic inflammation is also a big factor behind autoimmune diseases, such as Hashimoto's thyroiditis. (As the name suggests, anything ending in "itis" indicates inflammation.)

In fact, the researchers found that different genes that code for different inflammatory cytokines can influence the severity of Hashimoto. NAC can help reduce this inflammation. 


In one study, researchers found that this supplement provides anti-inflammatory benefits while increasing superoxide dismutase (SOD) enzymes (which fight against reactive harmful oxidative molecules), glutathione, and glutathione S-transferase(GST). (The latter two enzymes also work against harmful oxidative molecules.) The researchers concluded that NAC has both anti-inflammatory and anti-ulcer effects.

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NAC & other medications

Although NAC is safe for most populations, it can interact with some medications. Do not use if you are taking the following drugs: 

ACE inhibitors, activated charcoal, antihypertensive drugs such as anticoagulants / antiplatelet drugs, anticoagulants, nitroglycerin (a vasodilator), chloroquine, metoclopramide or anticancer drugs. 


Even at high doses, the researchers found NAC to be safe and well tolerated. 

However, it is important to note that NAC can cause stomach upset, nausea, vomiting, and diarrhea when taken on an empty stomach, so it should be taken with food to reduce the possibility of these reactions.

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Consult a doctor before use if you suffer from asthma or you are pregnant or breastfeeding. If you are concerned about possible drug interactions, please speak with your functional medicine physician. 

As we know Inflammation interferes with healthy thyroid hormone levels, so the real key is to find the source of your inflammation and address it. Make sure you work with a functional doctor who will properly investigate every possible source. If you have a chronic infection like the Epstein-Barr virus, you need the right recovery plan to keep it under control. Or, if your gut is out of balance, you need a good plan for optimal gut health. 

You can immediately start with some of the strategies listed above to ensure healthy glutathione levels that can help improve T3 and rT3 levels. Your thyroid problems may be simply due to undiagnosed sources of inflammation, so get a thorough exam and you may be well on your way to optimal thyroid health.



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