Quick answer: A typical NAC supplement in the UK provides 500 to 600 mg of N-acetyl cysteine per daily serving, and 600 mg is the most common amount. Read the “per daily serving” column on the label, follow the pack instructions, and speak to your GP or pharmacist first if you take medicines, have asthma or are pregnant.
- 500 to 600 mg is typical. A NAC supplement in the UK most commonly provides 500 to 600 mg per day.
- Read the daily serving. Compare the “per daily serving” column, not just the amount per capsule.
- Follow the label. Take it with water, ideally with food, and do not exceed the stated dose.
- Ask first if needed. Check with your GP or pharmacist if you take medicines, have asthma or are pregnant.
- No medical promises. Food supplements cannot legally make medical claims, so be wary of any that do.
If you have searched for a NAC supplement recently, you are not alone. N-acetyl cysteine (NAC) is one of the most searched supplement ingredients in the UK. Our earlier guide, What Is NAC (N-Acetyl Cysteine)?, explains what the molecule is. This article answers the practical follow-up questions: how much is typically in a capsule, when people take it, how to read a UK label and when to speak to a professional first.
01A quick recap: what NAC is
NAC is a form of the amino acid cysteine. Your body makes cysteine itself and also gets it from protein foods such as poultry, eggs, dairy, legumes and oats. In the UK, NAC is used in two very different ways:
- As a licensed medicine: prescribed or supplied in hospitals for specific uses, with dosing set by clinicians. This is a separate world.
- As a food supplement ingredient: sold in capsules, usually alongside other nutrients.
02How much is in a typical NAC supplement?
Looking at UK and EU supplement labels, NAC is most commonly sold in amounts of 500 to 600 mg per daily serving, with some products offering 1,000 mg or more. 600 mg is probably the single most common amount you will see.
What matters is the amount per daily serving, not per capsule. Some brands put 600 mg in one large capsule; others split it across two smaller capsules together with other ingredients. Always read the “per 2 capsules” (or similar) column on the nutrition panel.
Compare any NAC supplement by the amount per daily serving, not by the amount in a single capsule.
03How to read a UK supplement label
A UK food supplement label must show:
| Product category | The name of the category of nutrients or substances, for example “food supplement” |
|---|---|
| Daily amount | The recommended daily amount, and a warning not to exceed it |
| Balanced diet statement | A statement that supplements should not replace a varied diet |
| Children | A statement to keep the product out of reach of young children |
| Amounts | The amount of each nutrient or substance per daily serving |
04When do people take NAC?
There is no single “right” time to take a NAC supplement, and the label instructions always come first. Common habits include:
- With a meal, which some people find more comfortable for the stomach.
- With a full glass of water.
- At the same time every day: consistency makes it easier to remember.
05Who should check with a GP or pharmacist first?
Speak to a healthcare professional before taking a NAC supplement if any of these apply to you:
- Prescription medicines: particularly for blood pressure, heart conditions or blood thinning.
- Asthma.
- Pregnancy: you are pregnant, breastfeeding or trying to conceive.
- Under 18: most NAC supplement products are intended for adults.
- Digestive concerns: you have a stomach or bowel condition, or are waiting for tests.
- Surgery: you are about to have an operation.
Reported side effects at supplement amounts are usually digestive, such as a sensitive stomach or nausea, but everyone can react differently. Stop and seek advice if something does not feel right. The NHS medicines A to Z is a reliable starting point for medicine information.
06NAC on its own vs in a combination
You will find a NAC supplement sold in two main formats:
NAC on its own
- Single ingredient
- Usually 600 mg per capsule
Gives you control over each ingredient you take separately.
NAC in a combination formula
- Several ingredients
- One daily routine
NAC sits alongside vitamins, botanicals or other ingredients, which can be more convenient if you were going to take them anyway.
Neither is automatically better. Just check that you are not doubling up: if you take a multivitamin plus a combination formula, add up the totals for each nutrient.
07How to choose a NAC supplement in the UK
| Amount per daily serving | 600 mg a day is common; make sure you compare like with like |
|---|---|
| Capsule type | Vegan HPMC capsules suit vegetarians and vegans |
| Other ingredients | Fillers such as rice flour and anti-caking agents (silicon dioxide, magnesium stearate) are normal in small amounts |
| UK company and address | Gives you a clear contact for questions and returns |
| Claims | Avoid products making medical promises; those claims are not allowed on food supplements |
| Days per pack | Check how many days a pack lasts at the recommended daily amount |
For more background, read our guides to what NAC is, Pylopassâ„¢ explained and gut health, diet and daily habits.
08Where StarBiome Pylori fits
StarBiome Pylori from London Health Star is a combination food supplement. Each daily serving of two vegan capsules contains 600 mg NAC alongside Pylopassâ„¢, chamomile extract and vitamin B12. One pack of 60 capsules lasts 30 days.
A food supplement with Pylopassâ„¢, NAC, chamomile and vitamin B12. Each daily dose of 2 vegan capsules contains:
- Pylopassâ„¢ (Lactobacillus reuteri DSM 17648, inactivated)200 mg
- N-acetyl cysteine (NAC)600 mg
- Chamomile extract37.5 mg
- Vitamin B12 (as methylcobalamin)25 µg (1000% NRV)
Vitamin B12 contributes to the reduction of tiredness and fatigue, to normal energy-yielding metabolism and to the normal function of the immune system.
Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.
09Frequently asked questions
What is a typical NAC supplement amount in the UK?
A typical NAC supplement sold in the UK provides 500 to 600 mg per daily serving, and 600 mg is the most common amount. Always follow the amount on the pack and do not exceed the recommended daily dose.
Can I take NAC on an empty stomach?
Some people do, but many find it more comfortable with food. Follow the label instructions and ask your pharmacist if you are unsure.
Why does NAC smell of sulphur?
NAC contains sulphur, so a mild sulphur smell is normal for the ingredient and is not a sign that the product has gone off. Keep the lid closed and store the pack away from heat and moisture.
Is NAC a medicine or a supplement in the UK?
Both exist. The same molecule, called acetylcysteine, is used in licensed medicines, and NAC is also sold as an ingredient in food supplements. Food supplements are regulated as food, not medicines, and cannot make medical claims.
Can I take NAC with other supplements?
Often yes, but add up the total amount of each nutrient across all the products you take, and check with a pharmacist first if you take prescription medicines.
10Sources
Disclaimer: this article is general information, not medical advice. Regulatory positions can change. Speak to your GP or pharmacist about your own situation.
- NHS. Medicines A to Z. https://www.nhs.uk/medicines/
- GOV.UK. Food supplements: guidance and FAQs. https://www.gov.uk/government/publications/food-supplements-guidance-and-faqs
- Food Standards Agency. Food supplements. https://www.food.gov.uk/business-guidance/food-supplements
- Department of Health and Social Care (GOV.UK). Great Britain nutrition and health claims (NHC) register. https://www.gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
