NAC (N-Acetyl Cysteine) vs Soy Protein Isolate
Immune vs Protein · evidence-backed comparison
- • NAC (N-Acetyl Cysteine) has the stronger evidence base (strong (multiple rcts / meta-analyses)).
- • NAC (N-Acetyl Cysteine) is cheaper per serving ($0.22 vs $0.60).
- • Soy Protein Isolate has higher bioavailability (better absorption).
Side-by-side traits
| Trait | NAC (N-Acetyl Cysteine) | Soy Protein Isolate |
|---|---|---|
Category | Immune | Protein |
Active compound | N-acetyl L-cysteine | Soy isoflavones + amino acid blend |
Form available | Capsule, Powder | Powder |
Source | synthetic | plant |
Typical dose | 600–1800 mg daily | 25–40 g per serving |
Dose range | 600–1800 mg | 25–40 g |
Loading protocol | — | — |
Best taken with | empty stomach or with food | water or plant milk |
Best time of day | any | post-workout |
Bioavailability How efficiently the body absorbs and utilizes the compound. | Moderate (3/5) | High (4/5) |
Onset time | Acute and cumulative | Acute: 45–75 min |
Half-life | ~6 hours | — |
Evidence level Quality and quantity of human research. | Strong (multiple RCTs / meta-analyses) | Moderate (some RCTs) |
Overall effect Subjective effect magnitude. | Moderate (3/5) | Moderate (3/5) |
Muscle / strength | Low (2/5) | High (4/5) |
Physical energy | Low (2/5) | Low (2/5) |
Focus / cognition | Low (2/5) | Very Low (1/5) |
Mood / stress | Moderate (3/5) | Low (2/5) |
Sleep quality | Very Low (1/5) | Low (2/5) |
Immunity | High (4/5) | Low (2/5) |
Recovery Post-exercise recovery support. | Moderate (3/5) | High (4/5) |
Longevity / healthspan | High (4/5) | High (4/5) |
Safety rating 5 = exceptionally well-tolerated; 1 = significant risk profile. | High (4/5) | High (4/5) |
Price per serving Approximate USD per typical daily dose. | $0.22 | $0.60 |
Vegan friendly | Yes | Yes |
Gluten free | Yes | Yes |
3rd-party tested | Yes | Yes |
About NAC (N-Acetyl Cysteine)
Glutathione precursor used clinically for liver protection (acetaminophen overdose). Strong evidence for OCD, COPD, and PCOS.
About Soy Protein Isolate
Complete plant protein with all 9 EAAs. Equivalent muscle-building to whey in older adults; mild cardio-protective effects from isoflavones.
Vetted brands, third-party testing, ships worldwide.
Vetted brands, third-party testing, ships worldwide.
NAC (N-Acetyl Cysteine) safety
Common side effects:
- • Sulfur smell
- • GI upset
- • Headache
Avoid if:
- • Asthma (rare bronchospasm)
Drug interactions:
- • Nitroglycerin
- • Anticoagulants
- • Activated charcoal
Soy Protein Isolate safety
Common side effects:
- • Mild estrogen-mimicking (debated, minor)
Avoid if:
- • Soy allergy
- • Hormone-sensitive cancers (consult MD)
Drug interactions:
- • Thyroid meds (levothyroxine)
Common uses
- • Liver protection
- • Lung health
- • OCD / mental health
- • PCOS
Stacks well with: Vitamin C, Selenium (Selenomethionine)
Common uses
- • Vegan muscle gain
- • Heart health
- • Menopause support
Stacks well with: Creatine Monohydrate
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Medical disclaimer
SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements — especially if you are pregnant, breastfeeding, take prescription medication, or have a chronic condition.