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How Long Does It Take for NAC Supplements to Work?

If you are considering adding an NAC supplement to your daily routine, whether for detoxing, lung health, or anxiety, you probably have many questions about this popular nutrient and want to know how to get the best experience.

Since the early 1990s when they became available to the public, NAC supplements have maintained their position as the all-star of antioxidant formulas due to the nutrient’s role in manufacturing glutathione, the body’s most important antioxidant.

With its wide application and health benefits, NAC provides potent yet natural dietary support for respiratory health, detoxification, immune support, mood balance, athletic performance and female fertility, among a myriad of other science-backed benefits.* In fact, a study review published in Cell Journal described NAC as a “safe and inexpensive” natural health aid.*  

Before NAC supplements became available over the counter, the nutrient had been approved in clinical settings as a mucolytic to support respiratory function and later as an effective detoxifier. It is so powerful and effective that in 2020, the FDA considered banning it as a supplement. Thankfully, the FDA reversed its position and NAC supplements continue to be accessible over the counter.  

And with scientists regularly discovering new variants of Covid-19 and flu viruses, NAC is more popular than ever.

Get to know NAC and what to expect.

What does NAC stand for? What is NAC supplement?

Short for N-acetyl-cysteine, NAC is the supplement form of an amino acid called cysteine that’s found in high-protein foods, such as beef, eggs, dairy and legumes. While food sources are important to avoid a nutrient deficiency, consuming NAC in supplement form ensures your body has the therapeutic levels needed to support more intensive benefits. And if you follow a vegan or vegetarian diet, you may benefit from an NAC supplement, since the most concentrated food sources are animal-based.

What does NAC do?

NAC plays an essential role in many systems. Here’s a look at the key roles it plays in maintaining optimal health:

Glutathione Production

When you take NAC, it is swiftly broken down inside the body where it combines with other amino acids to form the most powerful antioxidant in the body -- glutathione. Glutathione helps to protect cells from toxins and reduce damage caused by free radicals, as well as help build and repair tissue.

Oxidation Protection

Regarded as the body’s most vital antioxidant, glutathione is a known immune system booster that fights oxidative stress and inflammation, which can contribute to a number of conditions that affect the heart, liver and even fertility. Glutathione is heavily implicated in metabolic processes and helps protect cells from free radical damage.


NAC is known to help protect the liver from the effects of certain toxins and is so effective that it has a history of use to combat acetaminophen (paracetamol) toxicity. NAC is also believed to have neuroprotective properties and may be useful in preventing damage to the kidneys. It’s often used in conjunction with medications that may harm the internal organs.

Mood Balance

Research also suggests glutathione may function as a neurotransmitter, which is why it has shown the ability to influence the central nervous system, brain and mood. In fact, NAC has been studied as a natural support for certain mood disorders.

Most intriguing about NAC is that it may be a promising complement in managing a wide variety of mental health issues. Some studies indicate that NAC can help minimize negative self-talk and disruptive ruminations, which are seen in various issues related to mood and chemical imbalances.


More specifically, NAC has shown to be beneficial in addressing symptoms of anxiety and melancholy, and for improving sociability. A small study on anxiety revealed that symptom improvement was significantly correlated to changes in glutathione.

If you’re wondering how long it takes for NAC to work for anxiety, research timeframes range from about 8 to 12 weeks of daily intake for positive results.

Women’s Health

NAC supplement benefits for women, especially for fertility, offer a promising field of study. Women who have experienced problems with ovulation and pregnancy may find some relief in NAC’s positive effect on menstruation regularity, ovarian function, pregnancy and birth rates. Its anti-oxidative and anti-inflammatory effect can further support fertility, because research shows that women with certain ovarian conditions have higher levels of oxidative stress.    

Exercise Performance

NAC is popular among athletes, and anyone who wants to improve their physical performance. It can help lengthen the time to fatigue, meaning that you don’t get tired as fast due to NAC’s ability to manage lactic-acid build-up. NAC seems to be most effective for medium-intensity exercises.


NAC is a highly versatile nutrient used for a wide variety of health reasons. For that reason, NAC supplements can vary from pure NAC to a combination of complementary ingredients that support a specific goal or target a health issue.

For example, Body Kitchen formulated Mega NAC + Quercetin, a double duty formula that contains a research-backed amount of NAC (600mg) in combination with a proprietary black pepper extract shown to improve absorption by at least 30%, and a second potent antioxidant, quercetin. Together, these ingredients optimize the anti-oxidative power of the individual ingredients. So, if you are looking for a nutritional boost to support lung function and respiratory health, athletic performance, female fertility, anxious thoughts or other targeted issues, Mega NAC + Quercetin may be right for you.

To strengthen your natural defenses, you can combine your NAC supplement with other immune system boosters, such as black elderberry extract. Body Kitchen has created several bundles that include our potent NAC formula to boost your natural defenses in different ways and can be taken seasonally or all year long.

How much NAC should I take?

According to research, a daily dose ranging from 600 mg to 1,800 mg of NAC is considered safe and effective. You may start with a lower daily dose and increase as tolerated, breaking up the doses into 2-3 servings daily.

How long does it take for NAC to work?

Before it can go to work to help your body function at its best, NAC needs to be converted into L-Glutathione. This takes at least a full hour after you take your supplement. After an hour or two, you should start to feel an improvement in things like lung function and energy levels.

Some conditions may require longer-term use of NAC before you see any improvement, so it’s important to take it consistently.

When to take NAC — morning or night?

Wondering when to take NAC morning or night? The time of day when you take NAC will depend on why you’re taking it. If you plan to use NAC to promote athletic performance, it’s good to take it early in the day. Studies have shown that NAC can produce improved physical exercise performance, but only if it’s taken well before your workout or sporting event. It can take your body about an hour to break down NAC into L-Glutathione. For this reason, you’ll probably get the best results if you take your NAC supplements in the morning.

On the other hand, you may be taking NAC to help improve a lung condition. These conditions tend to be worse at night when you’re lying still and breathing more slowly. Mucus tends to build up in the lungs, making you short of breath in the morning and potentially disturbing your sleep. Taking NAC an hour or so before bed will give your body time to break the supplement down and produce L-Glutathione. The L-Glutathione can then go to work, helping you to breathe more easily. Also take into consideration that when your body is at rest, it can absorb nutrients at a greater capacity.

As with any supplement, it’s important to talk to your doctor before taking NAC. In particular, you need to check that NAC doesn’t interact with any medicines if you happen to be taking any. If you plan on using NAC to address a specific medical condition you should make sure that you’re also receiving any conventional medical treatment that you may need. It’s been shown that NAC can be useful in treating lung conditions in some people, but you may still need medication, exercise, and other interventions to stay healthy. Overall, it’s a very safe compound.


"The NAC has made a huge difference in suffering with allergies and breathing issues i have been dealing with"- Christopher

Mega NAC + Quercetin


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