Ingredient type

Amino Acids

Building blocks of protein and related compounds, such as L-carnitine and L-theanine, used in supplements for energy metabolism, focus and relaxation.

Betaine

Evidence: Limited

Betaine is a nutrient from beets and whole grains involved in methylation and liver metabolism. Meta-analyses disagree on body fat and show no effect ...

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L-carnitine

Evidence: Limited

L-carnitine helps transport fatty acids into mitochondria. A meta-analysis of 37 trials found a small average weight reduction, mainly in people with ...

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L-theanine

Evidence: Moderate

L-theanine is an amino acid from tea. Combined with caffeine, it produces small short-term improvements in attention and reaction time, but it has no ...

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