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Source Naturals, L-Leucine, 500 mg, 240 Capsules

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In Stock
  • Expiration Date: Aug 2020
  • Shipping Weight: 0.53 lbs (0.24 kg)
  • Product Code: SNS-02054
  • UPC Code: 021078020547
  • Package Quantity: 240 Capsules
  • Dimensions: 3.1 x 3.1 x 5.6 in, 0.45 lbs (0.2 kg)
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Product Overview


  • Amino Acid Supplement
  • Free-From
  • Energy Support

L-Leucine is an essential amino acid, specifically classified as a "branched-chain amino acid" (BCAA). BCAAs, especially leucine, stimulate muscle protein synthesis and may be the major fuel involved in anabolic reactions. This makes them especially important for body builders and other athletes in sports that demand explosive strength.

Suggested Use

2 to 3 capsules daily between meals.

Other Ingredients

Gelatin (capsule), silica, and magnesium stearate.

Hypoallergenic: contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.


Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.

Do not use if either tamper-evident seal is broken or missing. Keep out of the reach of children.

Supplement Facts
Serving Size: 3 Capsules
Servings per Container: 80
  Amount Per Serving % Daily Value
Calories 5  
L-Leucine 1.5 g
†Daily Value not established.
iHerb Customer Reviews
Extraordinary weight loss with severe side effects
In 2 weeks on Leucine I experienced rapid weight loss while eating non-diet foods, as much as I wanted, and walking and going up and down the stairs normally as only exercise. I had tremendous energy the first week, and felt my muscles becoming firm, this after having been put on steroids 3 years ago for 5 months, and that weight is near impossible to lose (almost none of my usual supplements helped). Well, on Leucine, I dropped 2 sizes in 2 weeks! This has been the easiest, most effortless and most rapid weight loss of my entire life. However right away I experienced some tremendous side effects: the first one was a shrill high-pitched noise inside my ears that simply would not stop. (I quit Leucine 2 days ago and just now realized the permanent maddening noise is gone.) That was on 1 pill per day (500mg). After about 1 week I decided I wanted more weight loss: I took 2 caps per day (1000mg). In addition to the ringing in my ears, I also experienced unbearable fatigue and hypersomnia: I found myself sleeping 2 shifts per 24 hrs, 8 and 9 hrs respectively. It was impossible for me to stay conscious. Also dealt with extreme anger (flying off he handle). Everyone is different, I will add that I'm female and not a body-builder, with pre-existing health problems. Perhaps lifting weights would metabolize the leucine faster and less the side effects? Also the first week I was eating a lot of protein (meat & eggs) and my understanding is the protein supplies the other BCAAs (isoleucine and valine) needed to balance out the leucine, so maybe the reason why I had less side effects during week 1. I did read that leucine inhibits tryptophan, which regulates serotonin in the brain but I could not find anything online about these side effects, except for the anger. I don't know if the side effects would have been less at 2 caps per day if I'd eaten protein daily, since I was unable to go grocery shopping due my state of inertia, I found myself without meat or eggs. I deduct only 1 star for the side effects but if I had to do it again, you bet! Losing the weight I put in 8 months in only 2 weeks was well worth it. I will have another go at leucine in a few weeks and will make sure to only take 1 cap per day and have plenty of meat during the time I'm on it. Hope this helps someone out there.
Sep 07, 2011

not good

Posted by 5640879658384811183 on Jul 04, 2016

I didn't see any difference,I am using over 3weeks no results,doesn't work for mee

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bad and very expensive

Posted by 4871441214480765874 on Oct 10, 2014

bad and very expensive

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Good product

Posted by Reviewer2849359 on Apr 26, 2014

Good for strength and great price.

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Wrong product ordered

Posted by 4776795722922697152 on Feb 09, 2014

I do not want to rate this as I haven't consumed it at all due to my mistake and haste of not really reading carefully the product's ingredients list, but since iHerb mandates a review with rates, so I guess 1 star it is, though NOT BECAUSE it is a bad product. I was looking for vege caps but wrongly bought this instead.

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Very Good

Posted by 4616651412503945927 on Dec 04, 2013

That's a very good amino.

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