Doctor Life L-Cysteine 600 mg — 100 capsules

Pack size: 100 capsules
Serving: 1 capsule
Servings per pack: 100

ShopAmino acids and proteins

Doctor Life

L-Cysteine 600 mg

A glutathione precursor in a capsule

49,99 zł

Provides a key precursor to glutathione
Formulated to support natural glutathione synthesis
Supports the metabolism of a sulfur-containing amino acid

Overview

A focused source of a building block for glutathione. L-Cysteine 600 mg provides adults with a sulfur-containing amino acid the body uses, among other roles, to produce glutathione, an important part of its internal cellular protection system.

At the heart of the formula / L-Cysteine 600 mg

Thoughtful support. Clear purpose.

01Provides a key precursor to glutathione
02Formulated to support natural glutathione synthesis
03Supports the metabolism of a sulfur-containing amino acid
04A focused, single-ingredient supplement
05One capsule for a simple daily routine
06More than three months of regular use

Doctor Life / 01

L-Cysteine 600 mg

Made for your daily routine.

Each capsule provides 600 mg of L-cysteine as the single active ingredient. The formula offers a clearly specified amino acid serving without a multicomponent blend.

Take one capsule daily, with or without food. The plant-based pullulan capsule is suitable for vegans and vegetarians. Each bottle provides a 100-day supply.

Doctor Life / 02

L-Cysteine 600 mg

Why does L-cysteine matter?

L-cysteine is a sulfur-containing amino acid used to make glutathione. It also helps form disulfide bonds that stabilize many proteins, including keratins. The body can make cysteine from other amino acids, and its availability helps regulate glutathione synthesis.

Doctor Life / 03

L-Cysteine 600 mg

What research informs L-Cysteine?

Metabolic research identifies cysteine as a key substrate for glutathione synthesis. Studies have examined how sulfur amino acid availability affects that process, including combinations of cysteine precursors and glycine in specific populations. Those findings do not establish the same effects from L-cysteine alone. This formula provides a specified amount of the amino acid.

Ingredients / Doctor Life

Every ingredient. Clearly explained.

Each ingredient, its form and quantity — in one place.

Serving1 capsule

Ingredient amounts for the servings shown in the table.
Ingredient	1 capsule
L-cysteine	600 mg

*NRV: Nutrient Reference Value

Full ingredient list

L-cysteine; capsule shell (bulking agent: pullulan).

How to use

Part of your daily rhythm.

How to use

Take 1 capsule daily, with or without food.

Important information

Do not exceed the recommended daily serving. Food supplements should not replace a varied diet. A balanced diet and a healthy lifestyle are recommended. Store at room temperature, away from sunlight and out of reach of young children.

Science & sources

Understand the formula.

These selected publications examine L-cysteine as a sulfur-containing amino acid and a key substrate the body uses to synthesize glutathione.

These publications concern the studied ingredients or formulas. They do not all evaluate the finished Doctor Life product, and research results do not guarantee individual outcomes.

01Glutathione synthesis

Shelly C. Lu

Biochimica et Biophysica Acta (2013), 1830(5), 3143–3153. DOI: 10.1016/j.bbagen.2012.09.008; PMID: 22995213.

This review describes cysteine as a key sulfur-containing precursor to glutathione and identifies its availability as a major factor regulating synthesis. The publication concerns the ingredient, not the finished product, and provides context for L-cysteine in a glutathione-focused formula.

Read publication ↗

02Blood glutathione synthesis rates in healthy adults receiving a sulfur amino acid-free diet

J. Lyons, A. Rauh-Pfeiffer, Y.M. Yu et al.

Proceedings of the National Academy of Sciences USA (2000), 97(10), 5071–5076. DOI: 10.1073/pnas.090083297; PMID: 10792033.

In a controlled nutrition study in healthy men, restricting sulfur-containing amino acids reduced the rate of glutathione synthesis in the blood. The findings highlight the importance of cysteine and other sulfur-containing amino acids for this process.

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03Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation

Rajagopal V. Sekhar, Sanjeet G. Patel, Anuradha P. Guthikonda et al.

The American Journal of Clinical Nutrition (2011), 94(3), 847–853. DOI: 10.3945/ajcn.110.003483; PMID: 21795440.

In older participants with reduced glutathione synthesis, combined cysteine and glycine supplementation increased glutathione synthesis and concentrations and produced favorable changes in markers of oxidative stress. The study examined two precursors together, not L-cysteine alone or the finished Doctor Life product.

Read publication ↗

FAQ / L-Cysteine 600 mg

Good questions. Clear answers.

Talk to us ↗

Who is L-Cysteine 600 mg designed for?

It is designed for adults who want to supplement L-cysteine, one of the amino acids used to make glutathione, in a straightforward single-ingredient formula.

Why is glutathione a focus of the product?

L-cysteine is one of the three amino acids used to make glutathione. Its availability helps regulate synthesis. The formula supplies a clearly stated amount of this precursor.

How does L-cysteine differ from NAC?

NAC, or N-acetylcysteine, is an acetylated derivative of cysteine. This product supplies L-cysteine directly. Research on NAC should not automatically be applied to an L-cysteine supplement.

When should I take L-cysteine?

Take one capsule daily, with or without food. Choose a consistent time and do not exceed one capsule daily.

How long does one bottle last?

Each bottle contains 100 capsules, a 100-day supply at one capsule daily. Do not exceed the recommended serving.

Is it suitable for vegans and vegetarians?

Yes. The product uses a plant-based pullulan capsule and is suitable for vegans and vegetarians.

Can I combine L-cysteine with medication or other supplements?

If you take medication, have a chronic condition, or use several supplements, ask your doctor or pharmacist to review the combination.

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