Methylfolate (5-MTHF) vs NAC (N-Acetyl Cysteine)

Vitamin vs Immune · evidence-backed comparison

Quick take
  • NAC (N-Acetyl Cysteine) has the broader effect profile across the 9 effect categories.
  • Methylfolate (5-MTHF) has higher bioavailability (better absorption).

Side-by-side traits

TraitMethylfolate (5-MTHF)NAC (N-Acetyl Cysteine)
Category
VitaminImmune
Active compound
L-5-methyltetrahydrofolateN-acetyl L-cysteine
Form available
Capsule, TabletCapsule, Powder
Source
syntheticsynthetic
Typical dose
400–1000 mcg daily600–1800 mg daily
Dose range
400–1000 mcg600–1800 mg
Loading protocol
Best taken with
with foodempty stomach or with food
Best time of day
morningany
Bioavailability
How efficiently the body absorbs and utilizes the compound.
Very High (5/5)Moderate (3/5)
Onset time
Cumulative: 4–8 weeksAcute and cumulative
Half-life
~3 hours~6 hours
Evidence level
Quality and quantity of human research.
Strong (multiple RCTs / meta-analyses)Strong (multiple RCTs / meta-analyses)
Overall effect
Subjective effect magnitude.
Low (2/5)Moderate (3/5)
Muscle / strength
Very Low (1/5)Low (2/5)
Physical energy
Moderate (3/5)Low (2/5)
Focus / cognition
Moderate (3/5)Low (2/5)
Mood / stress
High (4/5)Moderate (3/5)
Sleep quality
Very Low (1/5)Very Low (1/5)
Immunity
Low (2/5)High (4/5)
Recovery
Post-exercise recovery support.
Very Low (1/5)Moderate (3/5)
Longevity / healthspan
Moderate (3/5)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$0.22
Vegan friendly
YesYes
Gluten free
YesYes
3rd-party tested
YesYes

About Methylfolate (5-MTHF)

Pre-methylated folate that bypasses MTHFR variants. Essential during pregnancy and for treatment-resistant depression with low folate.

Active compound: L-5-methyltetrahydrofolate
Forms: Capsule, Tablet
Onset: Cumulative: 4–8 weeks
moodMTHFRpregnancyhomocysteine

About NAC (N-Acetyl Cysteine)

Glutathione precursor used clinically for liver protection (acetaminophen overdose). Strong evidence for OCD, COPD, and PCOS.

Active compound: N-acetyl L-cysteine
Forms: Capsule, Powder
Onset: Acute and cumulative
glutathioneliverlungOCD

Methylfolate (5-MTHF) safety

Common side effects:

  • Anxiety / irritability (over-methylation)
  • Insomnia (PM use)

Avoid if:

  • Bipolar disorder

Drug interactions:

  • Methotrexate
  • Antiseizure meds

NAC (N-Acetyl Cysteine) safety

Common side effects:

  • Sulfur smell
  • GI upset
  • Headache

Avoid if:

  • Asthma (rare bronchospasm)

Drug interactions:

  • Nitroglycerin
  • Anticoagulants
  • Activated charcoal

Common uses

  • Pregnancy
  • MTHFR variants
  • Depression
  • Homocysteine

Stacks well with: Vitamin B12 (Methylcobalamin), Betaine Anhydrous

Common uses

  • Liver protection
  • Lung health
  • OCD / mental health
  • PCOS

Stacks well with: Vitamin C, Selenium (Selenomethionine)

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.