I’ve tried my fair share of supplements, but this NAC has officially become the darling of my daily routine. Popping a capsule each morning feels like I’m giving my body a little antioxidant pep talk—it’s the kind of small self-care that feels like a silent nod to the universe, like “Yes, today I’ve got you covered.” My first experience? I noticed it mostly in how I woke up: less groggy, like the morning fog somehow hit snooze. And when I hit the gym or even just walked up the stairs, my lungs felt less... bubble wrap—is that weird? But lighter, less effortful. It’s like my body is thanking me for the cleanup crew internally. On the more amusing side: yes, the supplements have that classic NAC sulfur scent—don’t worry, just brace yourself, tiptoe, and gulp. The effort is worth it (and somehow it’s oddly satisfying to tackle that smell head-on). I’ll be honest—on rough days, it’s become my little wellness anchor. Did it single-handedly fix all of life’s woes? Of course not. But did I feel smoother, more grounded, and a hair more functional? Absolutely. And when your supplement can make you feel just a bit steadier, that’s a win-worthy upgrade. What I love most about this bottle is knowing what’s inside: clean, no fluff, and a solid 120 servings. For me, it’s a quiet ritual that says, “I care about how I feel today,” and that’s more precious than any fancy packaging.
One 600 mg capsule of N-acetyl-L-cysteine (NAC), a form of the amino acid cysteine, to help support your body's own antioxidant defenses.* NAC is short for N-acetyl-L-cysteine. Amino acids are the small building blocks your body uses to make proteins.
- Antioxidant support.*
- Helps your body make glutathione, one of its own antioxidants.*
- Helps support your body's own antioxidant defenses.*
- Studied in healthy adults during intense exercise for its role in glutathione levels.*
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
| Serving Size | 1 Capsule |
|---|---|
| Servings Per Container | 120 |
| Amount Per Capsule | |
| N-Acetyl-L-Cysteine (NAC; Free-form) | 600 mg** |
| **Daily Value (DV) not established. | |
| Other Ingredients | Rice Flour, Hypromellose (Capsule). |
NAC (N‑Acetyl‑L‑Cysteine)
One 600 mg capsule of N-acetyl-L-cysteine (NAC), a form of the amino acid cysteine, to help support your body's own antioxidant defenses.*
What customers say
671 ratings and reviews
90% rated 4 or 5 stars
86 written reviews. Featured reviews come first. Tap a star row or change the sort to see every rating, including the lowest.
My long, irregular cycles have become so much more normal! I noticed a difference immediately and its been a few months of regular cycles now!
Felt a boost in energy the very next day. Not from a caffeine-type jitters, but just a smooth 'not tired' feeling. Didn't need my usual afternoon nap.
GREAT quality
Amazing product! It really is working for me, I’ve been taking it for about 3+ weeks. The quality is on point & you can tell by the smell. The benefits of NAC are endless and this product is phenomenal! Love wholesome story.
Good product. I like that it doesn't have a lot of extra ingredients. The size is easy to swallow. I can't tell if it is providing benefit yet.
This product has helped me so much for my overall health. Love this company and everything they do to help promote health.
Reviews are the personal opinions and experiences of individual customers. Wholesome Story did not pay or reward anyone for them, and we do not edit them. They are not our claims. Wholesome Story products are not intended to diagnose, treat, cure, or prevent any disease, and individual results vary.
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Learn the basics
What is NAC?
NAC (N-acetyl-L-cysteine) is a modified form of cysteine, an amino acid that contains sulfur.
In three steps
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Starts with L-cysteine
Reference books describe NAC as made from L-cysteine, an amino acid that contains sulfur.
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An acetyl group is added
Adding an acetyl group to cysteine gives N-acetyl-L-cysteine, or NAC.
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One 600 mg capsule
Each capsule holds 600 mg of free-form NAC.
| Name | N-Acetyl-L-Cysteine (NAC; Free-form) |
|---|---|
| Type of substance | A modified amino acid: the N-acetyl form of L-cysteine |
| Full chemical name and formula | (2R)-2-acetamido-3-sulfanylpropanoic acid; C5H9NO3S |
| Source | Reference books describe NAC as made from the amino acid L-cysteine. |
| Part used | Does not apply. NAC is a single compound, not a plant part. |
| Form in our product | Free-form NAC powder in a capsule |
| Amount per serving | 600 mg per capsule. One capsule is one serving. We suggest 1-3 servings as needed or as directed by a physician. |
| Daily Value | Not established |
| Other ingredients | Rice flour, hypromellose (capsule) |
| Capsule size and color | Size 00 (drawn 23.3 x 8.4 mm). Clear vegetarian capsule, white or clear. |
Questions and answers
What is NAC?
NAC is short for N-acetyl-L-cysteine, a modified form of the amino acid cysteine. Amino acids are molecules that join together to form proteins. Cysteine is an amino acid that contains sulfur. NAC is cysteine with an added acetyl group, a small cluster of atoms from acetic acid.
Where does NAC come from?
Reference books describe NAC as made from L-cysteine, an amino acid. Makers add an acetyl group to cysteine in a step called acetylation. We name the ingredient N-Acetyl-L-Cysteine (NAC; Free-form) on our label.
What does NAC look, taste and smell like, and why?
NAC is a white crystalline powder with a sour taste. One chemical reference describes a slight acetic smell, which means a smell like vinegar. A published review describes a strong smell like rotten eggs, which comes from the sulfur in NAC. Each NAC molecule has one sulfur atom.
What exactly is in our capsule?
Each capsule has 600 mg of N-acetyl-L-cysteine, and one capsule is one serving. The form is Free-form. The other ingredients are rice flour and hypromellose, which forms the capsule. NAC has no established Daily Value, and the capsules are vegetarian.
4 more questions about NAC
How does the body take in and clear NAC?
The gut takes in NAC quickly, but in one test only 4% to 9% reached the blood as NAC. The body removes the acetyl group and turns NAC into cysteine. Later products include sulfate and glutathione, a small molecule built from three amino acids. About 30% of a dose leaves the body in urine.
Is NAC found in food or in nature?
One published review reports that onions contain NAC, at about 45 mg per kilogram. Onions belong to a plant group called Allium. Cysteine, the amino acid that NAC is made from, occurs in many proteins.
Where does the name NAC come from?
The name describes the structure: N-acetyl means an acetyl group is attached to cysteine. The word cysteine comes from cystine, the name of a related amino acid. Cystine was discovered in 1810 and was isolated from animal horn in 1899. Merriam-Webster dates the word cysteine to 1884.
What do researchers study about NAC?
Researchers have studied how NAC is taken up and cleared after doses by mouth and by vein. They have studied its reactions with disulfide bonds, which are links between two sulfur atoms. They have studied the roles of hydrogen sulfide and related sulfur compounds in how NAC acts in cells. One study measured homocysteine, an amino acid in blood, and glutathione in healthy women taking NAC.
Sources (16)
We read these pages to write this tab. Each link opens in a new tab.
- PubChem, N-Acetyl-L-Cysteine (CID 12035)
- Britannica, cysteine
- MedlinePlus (NIH), Amino acids
- Merriam-Webster, acetyl
- Merriam-Webster, acetic
- Tenorio 2021, Antioxidants
- Olsson 1988, European Journal of Clinical Pharmacology (PubMed)
- Merriam-Webster, glutathione
- Salamon 2019, Antioxidants
- Merriam-Webster, cysteine
- Britannica, cystine
- Aldini 2018, Free Radical Research (PubMed)
- Pedre 2021, Pharmacology and Therapeutics (PubMed)
- Roes 2002, Clinical Chemistry and Laboratory Medicine (PubMed)
- NIH Office of Dietary Supplements, Vitamin B6 fact sheet for health professionals
- Wholesome Story product label and capsule guide
The short science, in plain words. This is background about the ingredient, not a claim about any product. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
- Size 00
- 0.91 in by 0.33 in
- 23 mm long
- 1 capsule a serving
- White/clear
| Active ingredient | N-Acetyl-L-Cysteine (NAC; Free-form) 600 mg per capsule |
|---|---|
| Serving | 1 capsule is 1 serving. Take 1-3 servings as needed. |
| Bottle size | 120 capsules (120 servings) |
| Other ingredients | Rice flour, hypromellose (capsule) |
| Capsule | Vegetarian capsule |
Take 1-3 servings (1 capsule per serving) as needed or as directed by a physician.
| Serving Size | 1 Capsule |
|---|---|
| Servings Per Container | 120 |
| Amount Per Capsule | |
| N-Acetyl-L-Cysteine (NAC; Free-form) | 600 mg** |
| **Daily Value (DV) not established. | |
| Other Ingredients | Rice Flour, Hypromellose (Capsule). |
Active Ingredient:
- N-Acetyl-L-Cysteine (NAC; Free-form)
Other Ingredients:
- Rice Flour, Hypromellose (Capsule)
Use only as directed. Consult your healthcare provider before use if you are contemplating pregnancy, pregnant, nursing, have any medical conditions, or use any medications. For adult use only. Keep this product out of reach of children. Do not use if tamper evident seal is broken or missing. Store in a cool, dry place.
Please use caution when taking this product if you have a history of any bleeding or clotting disorders, or if you are taking any other supplement or medication that may have anticoagulant or antiplatelet effects, as this combination may increase the risk of bleeding.
These are published papers about NAC: how it relates to cysteine and glutathione, how it acts in cells, and how the body absorbs it. Each one opens at PubMed. We list what each paper looked at, not what it proves. Some papers looked at lab models or at people with health conditions, not at healthy adults taking our product. They are background reading, not claims about our products. Talk with your healthcare provider.
Reviews of the evidence
- A review of how NAC supplies cysteine, the amino acid cells use to make glutathione.Atkuri 2007, Current opinion in pharmacology (opens the paper)narrative review
- A review of NAC's chemistry, its antioxidant role and how it relates to glutathione in cells.Tenorio 2021, Antioxidants (Basel) (opens the paper)narrative review
- A review of the uses of NAC described in published research.Mokhtari 2017, Cell journal (opens the paper)narrative review
How NAC works in cells
- A review of the ways NAC acts in cells, including hydrogen sulfide and sulfane sulfur species.Pedre 2021, Pharmacology & therapeutics (opens the paper)narrative review
- A review of the chemical reactions of NAC, including its antioxidant action and its reactions with disulphide bonds.Aldini 2018, Free radical research (opens the paper)narrative review
- A review of how NAC is converted to glutathione inside cells.Rushworth 2014, Pharmacology & therapeutics (opens the paper)narrative review
How the body absorbs and uses NAC
- A crossover study in six healthy volunteers measuring how NAC is taken up and cleared after oral and intravenous doses.Olsson 1988, European journal of clinical pharmacology (opens the paper)randomized crossover study
Clinical studies in people
- A study in nine healthy, non-pregnant women that measured blood levels of homocysteine and glutathione during oral NAC.Roes 2002, Clinical chemistry and laboratory medicine (opens the paper)clinical study
Supplements you can trust.
The FDA does not test supplements before they are sold. So we ask independent groups to test ours. Each mark below says what it covers and what it does not.
- 90-day guarantee
- Blended in the USA with domestic and international ingredients
- American company
Clean Label Project CertifiedAn outside group tested this product for heavy metals, pesticides and plastic chemicals that labels do not list.
What it checks
- A brand sends a product to Clean Label Project. Independent labs screen it for heavy metals, pesticides (including glyphosate), phthalates and bisphenols.
- Clean Label Project judges each product on its own against limits set by product type.
- Clean Label Project says certified products are tested again every year.
What it does not mean
- It does not mean the product has zero contaminants. Clean Label Project notes heavy metals occur naturally.
- It does not check that the label amounts are correct. That is a different test.
NSF Certified Gluten-FreeNSF tested this product and audited where it is made to check it meets a gluten-free limit.
What it checks
- NSF reviews the ingredients and tests the finished product for gluten.
- NSF audits the manufacturing site to check that gluten cannot get into the product.
What it does not mean
- It does not mean the product treats or helps with any condition, including celiac disease.
- It covers gluten only. It does not cover other allergens or other claims.
More questions? We're here to help
What is NAC and what does it do in the body?
NAC is a form of cysteine, an amino acid. Cells use cysteine to make glutathione, one of the body's own antioxidants. NAC supports your body's antioxidant defenses and cellular health.*
Why does my NAC smell like sulfur?
NAC contains sulfur, so it has a natural sulfur smell. Some people compare it to rotten eggs. If the seal was broken or missing when you got the bottle, do not use it and contact us.
Is it safe? How is it taken?
Follow the label. Suggested use: take 1-3 servings (1 capsule per serving) as needed or as directed by a physician.
Caution: Use only as directed. Consult your healthcare provider before use if you are contemplating pregnancy, pregnant, nursing, have any medical conditions, or use any medications. For adult use only. Keep this product out of reach of children. Do not use if tamper evident seal is broken or missing. Store in a cool, dry place.
Please use caution when taking this product if you have a history of any bleeding or clotting disorders, or if you are taking any other supplement or medication that may have anticoagulant or antiplatelet effects, as this combination may increase the risk of bleeding.
Can I take it with other supplements or medicines?
Ask your healthcare provider first. This is most important if you take any medication or supplement.
Please use caution if you have a history of any bleeding or clotting disorders, or if you take anything with anticoagulant or antiplatelet effects.
How long should I take it?
We cannot tell you how long to take it. Your healthcare provider can help you decide what is right for you.
What else is in the capsule?
The only active ingredient is NAC. The other ingredients are rice flour and hypromellose (the capsule). The capsules are vegetarian. Our products are made in a facility that also processes common food allergens, so we cannot promise the complete absence of any allergen unless it is listed on the label.
How many servings are in a bottle?
One capsule is one serving. A bottle has 120 capsules, so it has 120 servings.
Can I return it for a refund?
Yes. We offer a full refund on the purchase price minus shipping of our supplement products any time within 90 days (up to 3 bottles full or empty) for orders shipped in the United States. Please contact us through our Contact Us page for return instructions.
How big are the capsules?
Our NAC capsule is size 00, 0.91 inches by 0.33 inches, a little longer than a US nickel is wide. One serving is 1 capsule.
Where people go next.
Here is what the customers who stay with us do next.
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Nearly half of our NAC customers who reorder also order our inositol.From $27.95
Based on real orders from our customers.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Supply is based on the suggested use: 1 to 3 capsules a day. If your healthcare provider recommends a different dosage, your supply length may differ.