L-Carnitine

Mechanism of Action & Benefits:

L-Carnitine, a naturally occurring amino acid derivative, plays a crucial role in bodybuilding due to its involvement in energy production and muscle recovery. Here's how it works:

  1. Fat Oxidation: L-Carnitine helps transport fatty acids into the mitochondria of cells, where they are burned for energy. This process is particularly important during workouts when the body requires a lot of energy. By promoting fat oxidation, L-Carnitine can help enhance endurance and delay the onset of fatigue.

  2. Glycogen Preservation: L-Carnitine has been suggested to spare muscle glycogen during exercise by promoting fat oxidation. Preserving glycogen can enhance endurance and delay fatigue, allowing for longer and more intense workouts.

  3. Enhanced Insulin's Actions: L-Carnitine can enhance insulin's actions on muscle cells, helping to keep blood glucose levels low even after a carb-rich meal, while also aiding glycogen repletion. This can be beneficial for bodybuilders as it ensures a steady supply of energy for the muscles.

  4. Reduced Muscle Damage and Improved Recovery: L-Carnitine has been shown to significantly reduce muscle damage and improve recovery after exercise. It can also decrease muscle soreness, which can be beneficial for bodybuilders as it allows for more frequent and intense training sessions.

  5. Enhanced Exercise Performance: Some studies have shown that L-Carnitine supplementation can enhance exercise performance. For example, a study found significant increases in bench press lifting volume and leg press after L-Carnitine supplementation.

  6. Protection Against Muscle Breakdown: L-Carnitine has been shown to protect muscle tissue from exercise-induced damage. It can help reduce the breakdown of amino acids that make up muscle proteins for energy, thereby preventing muscle breakdown.

Side effects:

  1. Gastrointestinal Issues: High doses of L-Carnitine (approximately 3g/day) can cause nausea, vomiting, abdominal cramps, and diarrhea.

  2. Body Odor: Some users have reported a fishy body odor after taking L-Carnitine.

  3. Muscle Weakness: L-Carnitine can cause muscle weakness in people with uremia.

  4. Seizures: L-Carnitine may make seizures more likely in people who have had seizures before.

  5. Hypothyroidism: Taking L-Carnitine might make symptoms of hypothyroidism worse.

  6. Other Side Effects: Other less common side effects include depression, dizziness, impaired vision, loss of appetite or weight, and swelling in hands.

Interactions:

Injectable L-Carnitine, also known as Levocarnitine, is known to interact with certain medications. One of the most significant interactions is with Acenocoumarol, an anticoagulant used to slow blood clotting. L-Carnitine might increase the effects of Acenocoumarol, leading to an increased chance of bruising and bleeding. Therefore, if you're taking Acenocoumarol, your blood should be checked regularly, and the dose of your Acenocoumarol might need to be adjusted.

Another interaction is with Warfarin, another anticoagulant. Using Warfarin together with Levocarnitine may increase the risk of bleeding.

However, it's important to note that whether L-Carnitine interacts with Warfarin or Phenprocoumon is currently unknown.

Additionally, L-Carnitine might increase a brain chemical called serotonin. Therefore, it could interact with serotonergic drugs, which also increase serotonin levels.

Dosing Guidelines:

Here’s the part where we get into WHY we’re using an L-Carnitine injection instead of the standard oral capsules and powder formulations the fitness community has been using for so many decades.

Without getting too deep into the details, L-Carnitine is roughly 10-15% bioavailable if consumed orally while an injection is close to 100%.

The approximation used by bodybuilders is that 4 grams of L-Carnitine taken orally is roughly equal to 500 mg of L-Carnitine injected into the body.

Based on Hunter’s experience, the best L-Carnitine injection dose is 250 mg administered intramuscularly right before a fasted cardio session in the morning (using any insulin needle between a 28 gauge and 31 gauge size).

In the absence of carbohydrates from food, and when your body’s glycogen stores are depleted, it is more likely to rely on stored fats as an energy source.

However, there are a few things to note about this method:

  • You can titrate up to 500 mg per injection but that would be about the maximum you take per day

  • Pure L-Carnitine comes in a water-based solution, which means you don’t have to deal with the side effects of oil-based solutions (i.e. clumps around the injection site that cause bad scar tissue and/or significant post-inject pain)

  • Since L-Carnitine usually comes in ~500 mg/mL vials, DO NOT inject it fast (aim for 20-30 seconds per 1 mL)

  • It’s advised to experiment with different injection sites since you are going the intramuscular route. Hunter would experiment with injecting the entire 500 mg of L-Carnitine into his glutes one day, and then split the dose evenly between each shoulder if he was going to do an upper body workout, as an example.

Finally, be aware that 99% of the bodybuilding community uses L-Carnitine very differently from Hunter.

There are arguments over minutiae, but the general gist is L-Carnitine MUST be taken alongside ~60-90g fast-digesting carbohydrates around 30-60 minutes before a workout (and low-to-zero protein) in order to maximize L-Carnitine absorption.

(The more hardcore bodybuilders will opt for 1-2 IU of insulin with or instead of the carbohydrates to really ramp things up, but that’s not going to be discussed in this article).

I can’t say if the second way of using L-Carnitine is necessarily the best despite the overwhelming consensus but I’m going to trust Hunter’s judgment on this.

**The information provided on this post is intended solely for educational purposes and should not be considered a replacement for professional medical advice. Additionally, it is important to note that research chemicals are intended solely for laboratory study by professional researchers and are not intended for human consumption.

Back to blog

Leave a comment