NAC 90 - Supports Respiratory Function, Glutathione Production & Detoxification
One active. One job.
1,200 mg of NAC, and a capsule. That is the entire label.
There is no proprietary blend here, no supporting cast, and nothing to hide an amount behind. Two vegetarian capsules deliver 1,200 milligrams of N-acetyl L-cysteine, and the only other thing in the bottle is the capsule that holds it. We built it that way on purpose: when a single compound is doing the work, the only honest way to sell it is to print the number and let you check it.
Per serving1,200 mg NAC
Per capsule600 mg
Servings45 per bottle
Actives on panelOne
CapsuleVegetarian
Start here
Glutathione is manufactured, not swallowed.
Glutathione is the antioxidant your cells rely on most, and your body builds it internally from three amino acids: glutamate, glycine and cysteine. Two of those three are widely available in a normal diet. Cysteine is the one that runs short, and it is the one that sets the pace of the whole process. That single fact is the reason this product exists, and it is also why the most obvious approach — swallowing glutathione itself — turns out to be the least direct one.
There are three ways to go after glutathione status. They are not equivalent, and the differences are worth understanding before you spend money on any of them.
Approach 01
Oral reduced glutathione
Glutathione is a tripeptide, and the digestive tract handles peptides the way it handles all peptides: it takes them apart. Much of an oral dose is broken down into its constituent amino acids before absorption, and those amino acids do not reliably reassemble into functional glutathione inside the cell.
You are, in effect, paying a premium for cysteine that has been packaged inside two other amino acids you already get plenty of.
Approach 02
Liposomal glutathione
Liposomal delivery is a real technology and it addresses a real problem. Encapsulating glutathione in a phospholipid carrier shields it through the gut, and more of it reaches circulation intact. There are situations where that is exactly what somebody wants.
The trade-offs are cost per dose, a comparatively short window of effect, and the fact that supplying the finished molecule from outside does nothing to improve your own capacity to make it.
Approach 03 · This bottle
NAC, the substrate route
N-acetyl L-cysteine is an acetylated form of cysteine that is stable enough to survive the gut and be absorbed, then deacetylated to cysteine in the body. That cysteine is the raw material your cells were short of.
You are not delivering glutathione. You are removing the bottleneck in front of the machinery that makes it, which is a different and more durable proposition when the need is daily rather than occasional.
Mechanism described here reflects published research on cysteine availability and glutathione synthesis. It describes how the ingredient is understood to work in the body and is not a claim that this product treats, prevents or cures any condition.
The difference
A single-ingredient product has nowhere to hide. Most of them still find a way.
NAC is a commodity raw material, which means the interesting question is never whether a bottle contains it. The interesting questions are how much per capsule, how many capsules you have to take to reach the number on the front, and what else got into the capsule alongside it.
The industry standard
- "1200 mg" on the front panel, with the per-capsule amount buried and the serving quietly set at two, three or four capsules
- Magnesium stearate, silica, rice flour, titanium dioxide and colorants listed alongside a single active
- NAC folded into a proprietary detox or immune blend, so its individual amount is unknowable
- Marketing built on high-dose and clinical-setting literature that has nothing to do with a daily capsule
- Superlatives about purity and potency with no lot-specific document behind them
- No mention of the interactions NAC genuinely has, and no direction on who should check with a prescriber first
- Servings per container left vague so the bottle looks like a better value than it is
The IOH standard
- 600 mg per capsule, 1,200 mg per two-capsule serving, both printed on the panel
- Other ingredients line reads: vegetarian capsule, hypromellose and purified water. That is the complete list
- One active on the panel. Nothing shares the label and nothing is averaged into a blend
- Support language only, and an honest account of which research applies to a 1,200 mg daily amount and which does not
- We describe our facility and our testing process in specific terms rather than making a guarantee we cannot document per lot
- A safety and interaction section that names nitrate medication and antiplatelet drugs directly
- 45 full servings per bottle, stated plainly. Ninety capsules, two a day
Where it shows up
Four systems that run on glutathione
These are the areas NAC and cysteine availability have been studied for. Where you start from determines what you notice, and everyone starts somewhere different.
01
Glutathione substrate
Cysteine is the rate-limiting amino acid in glutathione synthesis. NAC supplies it in a form that survives digestion, which supports the body's own production of its primary intracellular antioxidant.
02
Liver and detoxification pathways
Phase II conjugation depends on glutathione as a working substrate, and the liver is where the largest pool of it sits. Supporting the raw material supports the pathway that uses it.
03
Respiratory function
Airway tissue carries a high oxidative load and NAC has a long research history in respiratory contexts. This formula supports normal respiratory function as part of daily antioxidant status.
04
Oxidative load and recovery
Hard training, poor sleep, alcohol, air quality and age all draw on the same redox capacity. NAC supports the body's antioxidant defenses against everyday oxidative stress.
The signature idea
Three inputs. One of them decides the output.
Glutathione is assembled from three amino acids in two enzymatic steps. In biochemistry, a process moving through several inputs runs at the speed of whichever input is scarcest — the rate-limiting step. For glutathione, in most people, that input is cysteine. This is the whole argument for the product on one screen.
L-GlutamateInput 01
Broadly available from dietary protein
GlycineInput 02
Broadly available from dietary protein and collagen
L-CysteineInput 03
Rate-limiting · the input this bottle addresses
Schematic. Bar widths illustrate the relative scarcity of each input in the pathway as described in the literature. They are not measured concentrations and they are not specific to any individual.
Step 01
Glutamate and cysteine are joined by glutamate-cysteine ligase to form gamma-glutamylcysteine. This is the committed, rate-limiting step of the pathway, and cysteine supply is what constrains it.
Step 02
Glutathione synthetase adds glycine to produce glutathione. Glycine is rarely the shortfall, so this step generally runs at whatever pace step one hands it.
The recycling loop
Used glutathione is oxidized and then reduced back to its active form rather than discarded. Both the recycling loop and new synthesis draw on cysteine, which is why the demand is continuous rather than occasional.
Everything else in the category is a variation on this diagram. Supply the finished molecule and you have added to the pool for a while. Supply the limiting input and you have raised the ceiling on how much of it your own cells can build, every day, without you thinking about it.
Inside the formula
One active, and the full context around the amount
Amounts below are per two-capsule serving, exactly as printed on the panel.
N-Acetyl L-Cysteine
1,200 mg
NAC · 600 mg per capsule · free-form, unstandardized single compound
Cysteine on its own is an awkward supplement ingredient. It oxidizes readily, it is unstable in solution, and free cysteine at higher amounts is not something anyone wants to build a daily product around. Acetylating the amino group solves that: N-acetyl L-cysteine is stable on the shelf, tolerated orally, absorbed, and then deacetylated in the body to release the cysteine that the glutathione pathway was waiting on.
That is the entire mechanism, and its simplicity is the reason NAC has one of the largest research literatures of any single compound sold in this category. It is also the reason we did not put anything else in the capsule. A supporting cast would only make the amount of the thing that matters harder to read.
One honest note on form: this is free-form NAC, not a liposomal or delayed-release version. Free-form is what the overwhelming majority of the human research used, and it is what the research amounts refer to. We would rather match the literature than sell you a delivery system the literature never tested.
- Supports the body's own production of glutathione
- Supports liver and detoxification pathways
- Supports normal respiratory function
- Supports the body's antioxidant defenses against everyday oxidative stress
- Supports healthy immune function
Amount in this bottle1,200 mg per day at the labeled serving of two capsules, taken as 600 mg per capsule.
Where that sitsHuman studies of oral NAC have most commonly used daily amounts in the 600 to 1,800 mg range, frequently split across the day. A 1,200 mg daily amount sits inside that range rather than below it, which is unusual enough in this category to be worth stating.
What we will not borrowA large share of the NAC literature comes from clinical settings, specific patient populations, intravenous administration, or amounts well above 1,800 mg per day. Those findings do not transfer to a daily capsule and we do not quote percentages from them here.
Splitting the servingTaking one capsule twice a day rather than two at once is a reasonable pattern and closer to how much of the research was dosed. Either way the daily total is the number that matters.
Read the panel
Supplement Facts
Serving Size: 2 Vegetarian Capsules
Servings Per Container: 45
Servings Per Container: 45
| Amount Per Serving | Amount | %DV |
|---|---|---|
| N-acetyl L-cysteine | 1200 mg | * |
* Daily Value (DV) not established.
Other Ingredients: Vegetarian Capsule (Hypromellose, Purified Water).
90 vegetarian capsules per bottle · 45 servings · 600 mg per capsule
The printed label is also shown in the product images at the top of this page
The short version
What it is
A single-ingredient N-acetyl L-cysteine capsule at 600 mg per capsule and 1,200 mg per serving, with nothing in the bottle but the active and a vegetarian capsule.
What it does
Supplies the rate-limiting amino acid your cells use to build glutathione, supporting antioxidant defense, liver and detoxification pathways, and normal respiratory function.
Who it's for
Adults carrying real oxidative load — hard training, travel, alcohol, poor air quality, age — who want the foundation of their antioxidant system supported rather than another finished antioxidant added on top.
How to take it
Two capsules daily with water, preferably on an empty stomach, or as directed by your healthcare provider. If that unsettles your stomach, take it with food instead.
Honest expectations
The first 90 days
NAC is not a product you feel. There is no switch, no stimulant effect and nothing that arrives in an afternoon. It changes the supply of raw material behind a system that runs quietly in the background — which is exactly why so many people take it for three weeks, feel nothing, and conclude it does nothing.
Days 1 – 14
Sort out timing and tolerance
Two capsules daily, same time. On an empty stomach absorption is better; with food it is gentler. Some people notice mild nausea or a sulfur note on an empty stomach — if that is you, move it to a meal or split it into one capsule twice a day. Write down where your energy and recovery sit today, because you will not trust your memory in two months.
Days 15 – 45
Watch what does not happen
Redox support tends to show up in the absence of things rather than the presence of them: the day after a hard session costing less than it used to, a bad week taking less out of you. That is a quiet signal and it is easy to talk yourself out of. Keep the habit and keep the notes.
Days 46 – 90
Judge it against day one
Ninety days is a fair trial and one bottle covers 45 of them, so plan for two. Compare against what you wrote down, not what you remember. If you track markers with your physician, this is a reasonable interval to look again.
How to shop this category
Six questions to ask any NAC bottle
Use these on us first, then use them on the next bottle you pick up anywhere. A single-ingredient product that cannot answer them is asking you to take its word for it.
| The question | IOH NAC 90 | Typical off-the-shelf NAC |
|---|---|---|
| How much NAC per capsule, not just per serving? | 600 mg per capsule, 1,200 mg per two-capsule serving. Both stated | Front panel shows the serving total while the per-capsule amount is left for you to work out |
| What else is in the capsule? | Vegetarian capsule, hypromellose and purified water. That is the complete other-ingredients line | Magnesium stearate, silica, rice flour, titanium dioxide or colorants alongside one active |
| Is the amount individually disclosed? | One active on the panel, printed on its own line with its own amount | Often folded into a proprietary detox, liver or immune blend where the amount is unknowable |
| How many full servings does the bottle hold? | 45 servings, stated on the panel. Ninety capsules at two per day | Capsule count promoted while the serving size and days-supply math go unmentioned |
| Does the copy match the amount in the bottle? | Claims and research context are described for a 1,200 mg daily amount, and we say when a study does not apply | High-dose and clinical-setting findings quoted as though they describe a daily capsule |
| Does it tell you about the interactions? | Nitrate medication, antiplatelet and anticoagulant drugs, and surgery timing named specifically below | No safety section, or a generic line about consulting a physician with no drug classes named |
Comparisons describe general patterns in the retail supplement category and are not directed at any specific brand or product.
Proof, not promises
What we will and won't say about this bottle
- We'll say the compound is studied. NAC has one of the deepest published research records of any single ingredient in this category, and the mechanism — cysteine as the rate-limiting input to glutathione synthesis — is basic, well-described biochemistry.
- We'll tell you exactly what is in it. 1,200 mg of N-acetyl L-cysteine per two-capsule serving, 600 mg per capsule, in a hypromellose capsule. There is no second ingredient to discuss.
- We'll tell you the amount is inside the research range. Most oral NAC studies in adults have used 600 to 1,800 mg per day. This is 1,200. We are not asking you to accept a token amount dressed up as a clinical one.
- We won't borrow the clinical-setting literature. A great deal of what is written about NAC comes from clinical settings, intravenous dosing and specific patient populations. None of that describes a daily capsule, and we will not quote its numbers to sell you one.
- We won't say it's a drug. It does not treat, prevent or cure anything, and it is not a substitute for something your physician prescribed.
- We won't promise a timeline. This is a substrate, not a stimulant. Ninety days is the honest window and there is nothing to feel on day three.
- We won't guarantee what we can't hand you. We will describe our facility and our testing process in specific terms. We will not print a purity and potency guarantee we cannot back with a document for your lot.
- We'll tell you when to call your doctor. NAC has real interactions. Nitrate medication and antiplatelet or anticoagulant drugs are named directly in the questions below.
Manufacturing and standardization
How this bottle is made
What follows is what we can describe about this specific product. Where a document would be needed to make a stronger statement, we have left the stronger statement out.
Facility
Manufactured in a US FDA-registered, cGMP-compliant facility. FDA registers facilities; it does not approve them, and we use the accurate word.
Testing
Testing is conducted at multiple stages of production, from incoming raw material through finished product.
Raw material
Free-form N-acetyl L-cysteine, a single identifiable compound rather than an extract. There is no standardization percentage to state because there is no plant matrix to standardize.
Capsule and excipients
Vegetarian hypromellose capsule with purified water. No magnesium stearate, no silica, no rice flour, no dioxides, no colorants.
Formula composition
One active. There are no gluten-containing, soy, dairy or animal-derived ingredients in this formula.
Serving arithmetic
90 capsules at 600 mg each. Two capsules daily gives 1,200 mg per day and 45 servings, which is 45 days from one bottle. Check it yourself.
Why we formulated this one
Cover the foundation before you buy the exotic thing.
Dr. Andreas Boettcher · Ironman finish
Dr. Andreas Boettcher, B.S., D.C., C.F.M.P.
Founder, It's Only Halftime
Ironman Triathlete / Master's Men's Physique Competitor / Medication-Free at 56 / 33 Years of Clinical Practice
Photograph shown for identification only. It is not a claim about what this product does.
In thirty-three years of practice I have watched people spend real money on the compound they heard about on a podcast while the ordinary things underneath it went unaddressed. Redox capacity is one of the ordinary things. It is not exciting, nobody is making content about it, and it quietly sets the ceiling on how well everything else works.
Glutathione is the piece of that system most people have heard of and the piece most people go after the wrong way. They buy glutathione. It is the intuitive move and it is the least direct one, because the body treats a swallowed tripeptide the way it treats every other peptide. What the pathway is actually short of is cysteine, and NAC is the practical, stable, well-studied way to hand it over.
I train hard, I race long, and I am fifty-six years old and not on a medication. That combination puts real oxidative load on my system and it is the reason NAC is in my own daily routine — not for anything I feel, but for what I would rather not spend the next twenty years paying for.
We built this one as a single ingredient at a real amount because that is what the science supports and because it made the label impossible to argue with. One active, 1,200 mg, 600 per capsule, a hypromellose shell and nothing else. When a customer asks me what is in it, I can answer in one sentence, and that is not something I can say about most of what is sold in this category.
This is what I reach for as a foundation. Everything else gets built on top of it.
Pairs well with
What NAC 90 stacks with
NAC handles the input side of the glutathione system. These two work the parts of the same system that NAC cannot reach on its own.
Liposomal Vitamin C
The recycling arm of the same redox system
Glutathione does not get used once and discarded. It cycles between a reduced, active form and an oxidized one, and something has to push it back. Vitamin C is one of the compounds that participates in that regeneration, and the relationship runs both directions — the two spare each other under load, which is why they are studied together as a redox pair rather than as two separate antioxidants.
Why the pair works
View Liposomal Vitamin C →
NAC increases the raw material available to build glutathione. Vitamin C supports getting the glutathione you already have back into its active form. One raises how much you can make, the other affects how much of what you have is usable at any given moment. Running only the input side means paying to synthesize molecules you are then failing to recycle.
Detox Binder
The exit route for what glutathione conjugates
Glutathione's role in detoxification is conjugation: it attaches to a compound to make it water-soluble and ready for elimination. Once conjugated metabolites are released into bile and reach the intestine, they still have to leave. If they do not, some of them are reabsorbed and the liver processes them again.
Why the pair works
View Detox Binder →
NAC supports the conjugation step. A binder supports the elimination step downstream of it. Supporting the first without the second means asking the liver to do the same work twice. One timing note that matters: binders are non-selective, so take Detox Binder at least two hours apart from NAC and from any medication, or the binder may carry off the thing you were trying to absorb.
One overlap worth knowing: CellCore ELITE also contains NAC, at 334 mg per serving. If you run both, your daily NAC total is roughly 1,534 mg rather than 1,200. That is still inside the range used in the adult research literature, but it is your number to know rather than one to discover, and it is worth mentioning to your physician if you take any of the medications named below.
I take this one every day, and not because of anything it makes me feel. I take it because the foundation is the part nobody notices until it is gone.
Stay Strong,
Dr. Andreas
Dr. Andreas Boettcher, B.S., D.C., C.F.M.P.
Questions, answered
Before you start
Read this part first
NAC is a single ingredient with real pharmacology, which means it has real interactions. It can amplify the blood-pressure-lowering effect of nitroglycerin and other nitrate medications. It has been reported to influence platelet function, which matters if you take an anticoagulant or antiplatelet drug or have a procedure scheduled. None of that makes it unsafe — it makes it active. If you take prescription medication, are pregnant or nursing, have a history of cystine kidney stones, or have surgery coming up, read the questions below and talk to your prescribing physician or pharmacist before you start.
I take nitroglycerin or another nitrate medication. Can I take this?
Not without your prescriber's sign-off, and this is the interaction to raise first. NAC has been shown to potentiate the vasodilating and blood-pressure-lowering effect of nitroglycerin, and the practical consequence can be a larger drop in blood pressure and a worse headache than you expect. That is a real, documented interaction rather than a theoretical one.
If you carry nitroglycerin for angina, or take an isosorbide mononitrate or dinitrate daily, bring this bottle to the conversation. Your cardiologist can tell you in two minutes whether it is workable for you.
I take a blood thinner or a daily aspirin.
Check with your prescriber before starting. NAC has been reported to influence platelet function, which means it can add to the effect of warfarin, clopidogrel, apixaban, rivaroxaban, aspirin or other antiplatelet and anticoagulant medication.
Your prescriber knows your history and, where relevant, your INR. That call is theirs, not ours and not a website's.
I have surgery or a dental procedure scheduled.
Stop taking it at least two weeks beforehand and tell your surgeon and anesthesiologist that you were on it. That is standard practice with any supplement that may affect platelet function. Put it in your phone on the day you book the procedure, not the week before.
Empty stomach or with food? The label says empty stomach.
Follow the label first: two capsules daily with water, preferably on an empty stomach. Absorption of amino acids is generally better without a meal competing for transport.
The trade-off is tolerance. A minority of people get mild nausea or notice a sulfur-like taste taking NAC on an empty stomach, and that is the single most common reason somebody stops. If that is you, take it with food. You may absorb somewhat less, but a slightly smaller amount taken every day for a year beats an optimally timed dose you abandoned in week two.
Can I split it into one capsule twice a day?
Yes, and there is a reasonable argument for it. Much of the human research on oral NAC dosed it in divided amounts across the day rather than as a single serving, and 600 mg happens to be the amount those studies most often used per dose. One capsule in the morning and one in the evening gives you the same 1,200 mg daily total with a smoother supply and, for some people, better tolerance.
Why not just take glutathione directly?
Because glutathione is a peptide and the digestive tract takes peptides apart. A large share of an oral reduced-glutathione dose is broken into its component amino acids before absorption, and those pieces do not reliably reassemble into functional glutathione inside the cell.
Liposomal glutathione is a legitimate answer to that problem and it does get more of the intact molecule into circulation. It costs considerably more per dose, its effect window is comparatively short, and it does nothing to improve your own capacity to produce glutathione. For a daily foundation, supplying the limiting raw material is the more durable approach. For a short, intensive push under specialist supervision, a liposomal form may have a role. They are different tools.
Will I feel anything?
Probably not, and any product in this category that promises you will is selling something other than biochemistry. NAC supports a background system. The honest expectation is that after a couple of months you notice hard days costing you less, and even that is a quiet signal rather than an obvious one. If a felt effect is what you are after, this is the wrong bottle and we would rather tell you now.
Can I take it long term?
It is designed as a daily foundation, so for most healthy adults yes. Two things worth holding onto. First, if you add another product containing NAC — ours or anyone's — redo the addition rather than assuming it does not stack. Second, if you are on it long term alongside prescription medication, a periodic review with your physician is the honest way to know whether it is still earning its place on your shelf.
Who should not take this?
Do not use it if you are pregnant, nursing or trying to become pregnant without your physician's direction. Do not give it to anyone under 18. Do not use it if you have a history of cystine kidney stones, because NAC can increase urinary cysteine excretion.
Use it only with your physician's sign-off if you take a nitrate medication, an anticoagulant or antiplatelet drug, or blood pressure medication; if you have asthma or another chronic respiratory condition; or if you have surgery scheduled. Stop and speak to your physician if you develop a rash, wheezing or any other reaction after starting.
Does it upset your stomach?
Most people tolerate it well. The reports that do come back are mild nausea and a sulfur note, both more likely on an empty stomach and both usually solved by moving it to a meal or splitting it into one capsule twice a day. If it persists past a week of doing that, stop and speak to your physician.
Is this a replacement for something my doctor prescribed?
No, and please do not treat it as one. This is a dietary supplement formulated to support normal physiological processes. It is not a drug, it is not a substitute for prescribed medication, and nobody here is suggesting you stop anything. If your goal is to reduce your reliance on a medication, that is a conversation to have with the physician who prescribed it, with labs and a plan — not a decision to make from a product page.
The foundation
The system that protects everything else is the one nobody thinks about until it is already behind.
Oxidative load does not arrive as an event. It accumulates while you are busy — the training you did not fully recover from, the four hours of sleep that became a habit, the drinks, the traffic, the year. Your cells absorb all of it through the same system, and that system runs on a molecule your body has to build from scratch, continuously, out of an amino acid most people are short of.
You cannot buy that molecule off a shelf in a form your cells will reliably use. What you can do is stop the pathway that makes it from running out of raw material. That is a small, unglamorous, entirely solvable problem, and it is what these ninety capsules are for.
One active. 1,200 milligrams. 600 per capsule. Forty-five days. Two capsules with water, every day, and a label short enough that you can verify every word of this page in about ten seconds.
The foundation is the cheapest thing you will ever fix and the most expensive thing to have ignored.
Supply the substrate · Support the system · Protect the next twenty years
This formula contains no trademarked, branded or licensed raw materials. N-acetyl L-cysteine is a non-proprietary compound.
Manufactured in a US FDA-registered facility. cGMP compliant. We use the highest quality raw materials available and conduct testing at various stages of production. All IOH Nutrition formulas meet or exceed cGMP quality standards.
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. Consult your physician before beginning any new supplement, particularly if you are pregnant or nursing, take prescription medication — including nitrate, anticoagulant or antiplatelet medication — have a history of kidney stones or a chronic respiratory condition, or have surgery scheduled.
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