NAC: the precursor to glutathione that your cells need

What is NAC?

NAC (N-acetyl-L-cysteine) is a stable, well-absorbable form of the amino acid cysteine. It was developed in the 1960s as a pharmaceutical substance and has been used clinically for over fifty years — most notably as an antidote for paracetamol overdose, where it replenishes glutathione stores in the liver. As a dietary supplement, NAC is taken to support the body's own production of glutathione.

Cysteine is the amino acid that limits the production of glutathione — it is the building block the body most often lacks during production. By providing cysteine in a stable, absorbable form, NAC removes that limitation.

The link with glutathione

Glutathione is a tripeptide consisting of three amino acids: glycine, glutamate, and cysteine. It is the most abundant endogenous antioxidant within the cell — present in virtually every cell, with particularly high concentrations in the liver, kidneys, and immune cells.

Glutathione fulfills multiple functions: it neutralizes free radicals, regenerates other antioxidants including vitamin C, supports the function of immune cells, and plays a central role in detoxification processes in the liver. Glutathione levels decline with age, and during oxidative stress, illness, and an unbalanced diet.

Why NAC often works better than glutathione itself

Regular oral glutathione has a fundamental absorption problem: the peptide bond holding the three amino acids together is broken down by stomach acid and digestive enzymes before the molecule can be absorbed intact. Research by Witschi et al. showed that oral glutathione is largely broken down in the gut.

NAC bypasses that problem entirely. As a derivative of a single amino acid, NAC is absorbed intact from the small intestine and converted into cysteine within the cell, where it is then used to produce glutathione. This production therefore takes place exactly where it is needed.

Liposomal glutathione — which we also offer — approaches the same problem differently: with physical protection instead of a chemical detour. A study in Antioxidants (2026, DOI: 10.3390/antiox15030354) confirmed that liposomal glutathione provides significantly higher glutathione levels in the blood than regular oral glutathione. NAC and liposomal glutathione work through different, complementary mechanisms.

What has been researched

NAC has one of the longest research histories of any supplement. The most important areas:

Liver function NAC is used clinically to restore glutathione stores in the liver after a paracetamol overdose. Research has also been conducted into liver support in other contexts, including fatty liver.
Respiratory tract NAC has been used for decades as a mucolytic agent for respiratory conditions. In various EU countries, it is available by prescription for this purpose.
Antioxidant status Multiple studies confirm that NAC supplementation increases intracellular glutathione levels, both in healthy individuals and in clinical groups.
Immune function The role NAC plays in the functioning of immune cells via glutathione-dependent pathways has been investigated.

NAC does not have an EFSA-approved health claim under EU Regulation 1924/2006. We therefore describe its biological role factually and refer to the research without making claims.

NAC or liposomal glutathione — what do you choose?

Both support glutathione levels in your cells, but via a different mechanism:

NAC supports the body's own production. More affordably priced, widely documented safety profile, suitable for daily support.
Liposomal glutathione provides glutathione directly. May be preferred if you want to increase blood glutathione levels faster. Pricier.
Together they complement each other: NAC supports production, liposomal glutathione provides direct replenishment. PPH Liposomal NAC already contains 50 mg of vitamin C, which supports the recycling of glutathione.

The PPH formula

PPH Liposomal NAC contains 300 mg of NAC and 50 mg of vitamin C per capsule, in our dry-liposomal form.

NAC 300 mg — N-acetyl-L-cysteine, precursor to glutathione
Vitamin C 50 mg — supports the recycling of glutathione
Liposomal delivery — for better absorption into the cell than regular NAC capsules
Plant-based HPMC capsule, GMO-free, without preservatives

Conclusion and next step

NAC is one of the best-researched and most clinically established supplements available. As a precursor to glutathione, with a fifty-year pharmaceutical history, it is a reliable way to support your body's most important antioxidant system.

Because your vitality is not optional — it is essential.

Frequently asked questions

You can take NAC at any time of the day. Taking it with a meal can prevent slight nausea. Some people take it in the morning, along with other antioxidants.

NAC works well with vitamin C (already in our formula) and with liposomal glutathione. It is generally easy to combine. If you use prescription medication — especially agents that are broken down by the liver — consult your doctor.

NAC has been used clinically for over fifty years and has a well-documented safety profile. In clinical research, dosages of 600 to 1,800 mg per day are often used. At supplement dosages (300–600 mg), it is generally well tolerated. During pregnancy, use only under medical supervision.

Sources

Witschi A. et al. (1992). The systemic availability of oral glutathione. European Journal of Clinical Pharmacology.
Rushworth G.F. & Megson I.L. (2014). Existing and potential therapeutic uses for N-acetylcysteine. Pharmacology & Therapeutics. pubmed.ncbi.nlm.nih.gov/24080471/
Richie J.P. et al. (2015). Randomised controlled trial of oral glutathione supplementation. European Journal of Nutrition. DOI: 10.1007/s00394-014-0706-z
MDPI Antioxidants (2026). Oral Liposomal Glutathione Bioavailability. DOI: 10.3390/antiox15030354