Evidence B · Good
Crosses BBB
Chronic (weeks)
The acetylated form of carnitine that crosses the blood-brain barrier. The focus is on neuroprotection, mental focus and central fatigue. It does not depend on insulin — ideal for low-carb / fasted use.
Dose500 mg–1g/day
TimingMorning
FoodNot required
SynergyBlack coffee + fasted Z2
When to prefer ALCAR over L-Carnitine Tartrate
- You are on a low-carb or ketogenic diet.
- Your main goal is cognition / mental clarity during the ultra.
- You want to avoid the TMA odor (ALCAR is absorbed faster).
- You plan to use it before fasted workouts (morning Z2).
Why it works fasted
Unlike L-Carnitine Tartrate (insulin-dependent), ALCAR is absorbed quickly even on an empty stomach. Combined with black coffee, it is the standard pre-workout "kit" for those who train fasted to target fat oxidation.
Product in use: LE Acetyl-L-Carnitine Arginate
Life Extension's Acetyl-L-Carnitine Arginate is an upgraded form of conventional ALCAR — it combines ALCAR with arginine to form Acetyl-L-Carnitine Arginate Dihydrochloride, which has greater absorption and longer duration than pure ALCAR HCl.
- Per capsule: 320 mg of Acetyl-L-Carnitine Arginate + 300 mg of Acetyl-L-Carnitine HCl = 620 mg of total ALCAR
- Dosage (label): 1 capsule 3×/day, fasted (morning + afternoon + pre-workout, for example)
- Bottle: 90 vegetable capsules = 30 days at the standard dose
- Price: $28.50 USD
- Cost/day: $0.95 (~R$4.89/dose @ 5.15)
💡 Why the "Arginate" form may be better: the arginine bound to ALCAR acts as a "carrier" across the blood-brain barrier and may extend plasma time. Studies show potentially superior cognitive effects compared to pure ALCAR HCl at the same doses, but direct clinical evidence comparing the two is limited.
⚠️ Fasted + 3×/day: the ideal dosing requires discipline — 3 doses throughout the day, all fasted (away from protein). If that does not fit your routine, simplifying to 2 doses (morning + mid-afternoon) still delivers ~70–80% of the benefit.
Comparison table
| Feature | ALCAR | L-Carnitine Tartrate |
|---|---|---|
| Main focus | Brain / Focus / Neuroprotection | Muscle / Fat burning |
| Insulin-dependent? | No | Yes (needs carbohydrate) |
| Best timing | Morning (fasted OK) | Pre-workout or lunch |
| Use in the ultra | Avoid the mental "crash" | Spare glycogen and reduce damage |