Citrulline and HMB (beta-hydroxy beta-methylbutyrate) are two supplements that have been studied for their potential benefits in supporting lean muscle growth. Here's an overview of their respective benefits:

Citrulline:

1. Increased Nitric Oxide Production: Citrulline is a precursor to arginine, which is a key amino acid in the production of nitric oxide. Nitric oxide helps to relax blood vessels, leading to improved blood flow. This enhanced blood flow can be beneficial for nutrient delivery to muscles during and after exercise.
2. Enhanced Exercise Performance: Citrulline supplementation has been associated with improved exercise performance, endurance, and reduced muscle soreness. This can indirectly support lean muscle growth by allowing individuals to train at higher intensities and recover more efficiently.
3. Ammonia Detoxification: Citrulline has been shown to aid in the removal of ammonia, a byproduct of protein metabolism, from the body. Reduced ammonia levels may contribute to better exercise performance and recovery.

HMB:

1. Muscle Protein Synthesis: HMB is a metabolite of the amino acid leucine, and it has been studied for its role in promoting muscle protein synthesis. This can be particularly beneficial for individuals aiming to build and preserve lean muscle mass.
2. Reduced Muscle Protein Breakdown: HMB has been suggested to inhibit muscle protein breakdown, especially during periods of muscle damage or catabolic conditions. This can contribute to a more positive net protein balance, favoring muscle growth.
3. Improved Strength and Power: Some research suggests that HMB supplementation may lead to increased strength and power, potentially enhancing performance during resistance training. This can positively impact the stimulus for muscle growth.
4. Recovery Support: HMB has been associated with reduced muscle soreness and faster recovery following intense exercise. This can allow individuals to train more frequently and consistently, promoting lean muscle gains over time.

It's important to note that individual responses to supplements can vary, and these benefits are generally observed in the context of a well-rounded training program and a balanced diet. Before incorporating any supplements into your routine, including citrulline or HMB, it's advisable to consult with a healthcare or nutrition professional to ensure they align with your specific fitness goals and health status. Additionally, obtaining nutrients through whole foods is always a preferred approach when possible.