Evidence supporting the use of: Leucine
For the health condition: Muscle Tone (lack of)
Synopsis
Source of validity: Scientific
Rating (out of 5): 4
Leucine is an essential branched-chain amino acid (BCAA) that plays a critical role in muscle protein synthesis and muscle health. Scientific research has validated its use in supporting and improving muscle tone, particularly in populations at risk for muscle loss, such as older adults or those experiencing muscle wasting (sarcopenia). Leucine directly stimulates the mammalian target of rapamycin (mTOR) pathway, which is a key regulator of muscle protein synthesis. Several clinical trials and mechanistic studies have shown that leucine supplementation, either alone or as part of BCAA or protein supplements, can enhance muscle protein synthesis, help preserve lean muscle mass, and improve muscle function when combined with resistance exercise or adequate nutrition.
A notable body of evidence demonstrates that leucine supplementation is effective in preventing or attenuating the decline in muscle mass and strength associated with aging or inactivity. For example, a meta-analysis published in the Journal of Nutrition (2021) concluded that leucine-enriched amino acid supplementation significantly improved muscle mass and function in older adults. However, while the evidence is robust for its role in muscle protein synthesis and preservation, there is less direct evidence for its use to "treat" poor muscle tone in the absence of underlying muscle loss or disease. The consensus remains strong for its supportive role in maintaining muscle health.
Other ingredients used for Muscle Tone (lack of)
adenosine 5-triphosphate disodium (ATP)alpha-ketoglutarate (AKG)
amino acids
ashwagandha
astaxanthin
beet
branched-chain amino acids
calcium
caterpillar mushroom
cissus quadrangularis
coenzyme Q10 (CoQ10)
conjugated linoleic acid (CLA)
cordyceps
creatine monohydrate
fish protein
l-isoleucine
l-arginine
l-carnitine
l-citrulline
l-leucine
l-valine
maca
magnesium
ornithine alpha-ketoglutarate
phytocannabinoids
potassium
sardines
black ginger
tongkat ali
Urolithin A
vitamin D
whey protein
atractylodes
cistanche
electrolytes blend (proprietary)
camphor oil
chickpea protein
brown rice protein
AMP-activated protein kinase (AMPK)
Aralia
Arginine Alpha Ketoglutarate
Antler
Arginine Creatine
Alpha-ketoisocaproic acid
Algal protein
Alpha hydroxyisocaproic acid
Animal protein
Beef Protein
Beef
Beef liver
Bovine Protein
beta-lactoglobulin
Banyan
Ba Ji Tian
BCAA
Casein
Chinese Silkvine
Chinese Mountain Ant
Cyathula
Chuchuhuasi
Creatine
Chicken
Deer Velvet
Egg
Ecdysteroids
Ecdysterone
Egg protein
Isoleucine
Milk Protein
Quinoa Protein
salt