L-Cysteine
L-Cysteine is an amino acid that supports detoxification, antioxidant production (via glutathione), and promotes healthy skin, hair, and nails.
L-Cysteine is a sulfur-containing amino acid that helps form glutathione, one of the body’s most important antioxidants.
It supports detoxification, respiratory health, and immune function, and plays a role in maintaining healthy skin and hair.
L-Cysteine is used for antioxidant protection and respiratory support. It is generally safe, especially in the form of N-acetyl cysteine (NAC).
Other names & forms of L-Cysteine supplement : cysteine, l-cysteine hcl, n-acetyl l-cysteine precursor, l-cysteine supplement
Possible Benefits
L-Cysteine is a semi-essential amino acid that serves as a precursor for glutathione synthesis, helping maintain intracellular antioxidant defenses and detoxification pathways.
- Helps support Detoxification & Cleansing by replenishing glutathione levels and enhancing phase II liver detoxification.
- Provides Anti-Aging benefits through potent antioxidant protection and reduction of oxidative stress.
- Supports Skin Health by promoting keratin production and maintaining collagen stability.
- May enhance Immunity by supporting lymphocyte function and oxidative defense in immune cells.
Side Effects
L-Cysteine acts as a precursor for glutathione synthesis and may support detox, but mild effects can occur as sulfur metabolism ramps up. Watch for:
- Possible mild gastrointestinal upset, nausea or diarrhea, especially on an empty stomach
- Occasional headache or dizziness during initial dosing
- Rare sulfurous odor in breath or sweat
- Temporary mild skin rash or itching, hypersensitivity reactions
- Very mild changes in urinary odor
Interactions
Possible interactions include:
- Antioxidant therapies: L-Cysteine’s role in glutathione synthesis complements NAC and glutathione; monitor sulfur amino acid load.
- Protein supplements: Cysteine alongside whey protein can support muscle recovery; balance total sulfur amino acid intake.
Precautions
Before adding L-Cysteine to your routine, ensure none of these apply. If they do, consult your healthcare provider:
- Individuals with peptic ulcers: May irritate gastric lining; take with food
- People with asthma: Rare bronchospasm risk; use cautiously
- Those with sulfur intolerance: Avoid if sensitive
- Pregnant or breastfeeding women: Limited data; stick to dietary sources unless advised
- Patients scheduled for surgery: Discontinue one week prior, possible anesthesia interactions
Studies
These studies provide scientific insights into L-Cysteine benefits:
No randomized clinical trials have evaluated L-cysteine supplementation for antioxidant support, skin health, or detoxification in humans.
Mechanistic studies indicate glutathione precursor potential, but clinical evidence from RCTs is absent.
Disclaimer: This page is for educational purposes and does not replace medical advice. If you're pregnant, have a condition, or take medication, speak with a qualified professional.
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