L-Carnitine (Tartrate) vs Magnesium L-Threonate
Performance vs Sleep · evidence-backed comparison
- • L-Carnitine (Tartrate) has the stronger evidence base (moderate (some rcts)).
- • L-Carnitine (Tartrate) is cheaper per serving ($0.60 vs $1.10).
- • Magnesium L-Threonate has a slightly cleaner safety profile.
- • Magnesium L-Threonate has higher bioavailability (better absorption).
Side-by-side traits
| Trait | L-Carnitine (Tartrate) | Magnesium L-Threonate |
|---|---|---|
Category | Performance | Sleep |
Active compound | L-carnitine L-tartrate | Magnesium L-threonate |
Form available | Powder, Capsule, Liquid | Capsule, Powder |
Source | synthetic | synthetic |
Typical dose | 1–3 g daily | 1.5–2 g (≈144 mg elemental Mg) |
Dose range | 1–3 g | 1500–2000 mg |
Loading protocol | — | — |
Best taken with | carbs (improves absorption) | evening |
Best time of day | post-workout | evening |
Bioavailability How efficiently the body absorbs and utilizes the compound. | Moderate (3/5) | Very High (5/5) |
Onset time | Cumulative: 4–12 weeks | Cumulative: 4–12 weeks |
Half-life | ~15 hours | — |
Evidence level Quality and quantity of human research. | Moderate (some RCTs) | Limited (small studies) |
Overall effect Subjective effect magnitude. | Low (2/5) | Moderate (3/5) |
Muscle / strength | Moderate (3/5) | Very Low (1/5) |
Physical energy | Moderate (3/5) | Very Low (1/5) |
Focus / cognition | Low (2/5) | High (4/5) |
Mood / stress | Low (2/5) | Moderate (3/5) |
Sleep quality | Very Low (1/5) | High (4/5) |
Immunity | Very Low (1/5) | Very Low (1/5) |
Recovery Post-exercise recovery support. | High (4/5) | Very Low (1/5) |
Longevity / healthspan | Moderate (3/5) | Moderate (3/5) |
Safety rating 5 = exceptionally well-tolerated; 1 = significant risk profile. | High (4/5) | Very High (5/5) |
Price per serving Approximate USD per typical daily dose. | $0.60 | $1.10 |
Vegan friendly | No | Yes |
Gluten free | Yes | Yes |
3rd-party tested | Yes | Yes |
About L-Carnitine (Tartrate)
Shuttle for fatty acids into mitochondria. Modest fat-burning effects; stronger evidence for recovery and androgen receptor density.
About Magnesium L-Threonate
Only magnesium form proven to cross the blood-brain barrier in animals. Marketed for cognitive aging and sleep, but premium-priced.
Vetted brands, third-party testing, ships worldwide.
Vetted brands, third-party testing, ships worldwide.
L-Carnitine (Tartrate) safety
Common side effects:
- • Fishy body odor (high doses)
- • GI upset
Avoid if:
- • Hypothyroidism
- • Seizure disorders
Drug interactions:
- • Warfarin
- • Thyroid hormone
Magnesium L-Threonate safety
Common side effects:
- • Drowsiness
- • Headache (rare)
Avoid if:
- • Severe kidney disease
Drug interactions:
- • Bisphosphonates
Common uses
- • Fat loss
- • Recovery
- • Endurance
- • Cognitive (acetyl-L-carnitine form)
Stacks well with: Creatine Monohydrate
Common uses
- • Cognitive aging
- • Deep sleep
- • Memory
Stacks well with: Zinc, Vitamin D3
Related comparisons
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.