Leucine

Leucine is one of the nine essential amino acids that humans require from their diet. It is crucial for various physiological processes and is particularly prevalent in foods like meat, fish, and dairy. It is also a popular dietary supplement, especially among athletes, to aid in muscle repair and growth.

2. FDA Indications

Leucine is not an FDA-approved drug but is commonly used as a dietary supplement for muscle protein synthesis and sometimes for enhancing athletic performance.

3. Off-label Indications

While not conclusive, some early research suggests that Leucine may reduce NAD+ requirements and improve the efficiency of Semaglutide, a GLP-1 receptor agonist used for type 2 diabetes and weight loss.

4. Mechanism of Action

Leucine serves primarily as a building block for proteins but also has more complex roles. It activates the mTOR pathway, which stimulates muscle protein synthesis and inhibits protein degradation. It may also regulate blood sugar levels by moderating insulin into the body.

5. Side Effects

Excessive consumption of Leucine can lead to skin tingling, and in extreme cases, a buildup of ammonia in the body.

6. Drug Interactions

Because Leucine activates the mTOR pathway, it could potentially interact with drugs like rapamycin, which inhibits the same pathway.

7. Contraindications

Individuals with Maple Syrup Urine Disease (MSUD), a rare metabolic disorder, should avoid Leucine supplementation.

8. Warnings and Precautions

Consult your healthcare provider if you are taking other medications or have liver or kidney issues before using Leucine as a supplement.

9. Clinical Evidence

Most research on Leucine focuses on its role in muscle protein synthesis and athletic performance. Emerging research suggests it may have a role in improving metabolic health.

10. Adverse Reactions

In rare cases, excessive Leucine intake can lead to a form of protein poisoning known as 'rabbit starvation.'

11. Use in Specific Populations

Pregnant or breastfeeding women, as well as individuals with liver or kidney disorders, should consult a healthcare provider before using Leucine.