Thorne Amino Complex - Lemon Review

Thorne's Amino Complex in Lemon is a clinically validated essential amino acid and BCAA formula designed to support muscles and training. The product is sold as a lemon-flavored powder that is lightly sweetened and easy to drink, and the page says it is NSF Certified for Sport and tested for banned substances. The formula is positioned to promote the growth of lean muscle mass, enhance muscle strength, support recovery, help muscle repair, and reduce muscle soreness after exercise. The page also lists support for cellular energy production, metabolism, healthy blood sugar already within the normal range, cardiovascular health, and connective tissue strength. The page explains that amino acids are the building blocks of protein and that the body uses them for muscle gain and for functions including enzyme production, hormone regulation, cognitive ability, neurotransmitter balance, metabolism, and energy production. It notes that as people age they lose muscle mass, which can cause other health issues, so promoting lean muscle mass is presented as important. Of the twenty amino acids that make up protein, nine are described as essential amino acids that the body cannot produce itself and must come from diet or supplementation. Each serving is one scoop, and the container holds 30 servings. The label lists L-Leucine at 1.25 g, L-Isoleucine at 625 mg, L-Valine at 625 mg, L-Lysine as L-Lysine Chloride at 650 mg, L-Threonine at 350 mg, L-Histidine at 150 mg, L-Phenylalanine at 100 mg, L-Methionine at 50 mg, L-Tryptophan at 20 mg, L-Cystine at 150 mg, and L-Tyrosine at 30 mg. The page describes it as a full spectrum of EAAs, including all nine essential amino acids. Directions say to mix one scoop with at least eight ounces of water and to take one to two times daily, or as recommended by a health-care practitioner. The page advises taking it after a workout to support recovery, and says it mixes easily in warm or cold liquid. The product is described as suitable for athletes training and seeking fitness, for older people who need to preserve muscle mass, for a person recovering from muscle injury or overuse, and for anyone needing readily bioavailable amino acids for protein building. The page says it is an ideal formula for active individuals, people managing calories, or anyone who has difficulty consuming whole foods or protein powders, particularly after heavy exercise. The product is vegan, gluten-free, dairy-free, and soy-free. It is made with flavors and sweeteners derived from natural flavors and is sweetened with rebaudioside A. The page notes it is available in two flavors, lemon and berry, and in bulk powder or individual stick pack servings. Thorne states that every batch of an NSF Certified for Sport product is tested for label claims and for the absence of nearly 300 substances banned by many major athletic organizations. Warnings on the page include a California Proposition 65 notice about lead exposure, a statement that the product is contraindicated for anyone with a history of hypersensitivity to its ingredients, advice that pregnant or nursing people should not use it, and a note that New York law prohibits sale to individuals under eighteen. The page states there are no known adverse interactions or contraindications at publication date.

Tier ⓘ
Tier 3 · Rank 8
Tier 3 · Reviewed. Strong review agreement, with limited or early support from human studies. Rank 8 within Tier 3 for Muscle and Strength; 31 of 103 overall. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
71 /100
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
78% of 6,065
Biohacker Mentions
10 of 10
Cost per month
$52

Study, Trial or Testing Result Summary

Members Only113 human studies · 48 improved

5 of these 113 human studies gave the ingredient by drip, not by mouth.

113 human studies48 improved32 no effect26,516 people studied

This powder is a mix of essential amino acids, led by leucine at a full studied dose. Leucine-rich protein supplements improved muscle strength, mass and performance in older adults with muscle loss [1], and a leucine and vitamin D enriched whey drink added a small amount of muscle [2]. A larger pooled analysis also found gains, but rated the evidence low quality [3]. Leucine taken alone mostly did not help, even with strength training [4][5][6]. Isoleucine and valine, at full doses, have only been tested inside branched-chain amino acid mixes. One small trial found a small lean muscle gain [7], and a review linked these mixes to better recovery and strength after lifting [8]. Larger trials found no muscle or strength benefit [9][10][11]. Lysine support comes from mixes with other compounds, so its own role is unclear [12][13]. An amino acid drink with threonine, phenylalanine and methionine added nothing to strength training in older men [14]. Histidine, cystine, tyrosine and tryptophan are below any studied amount and have no supplement evidence for muscle [15][16]. Animal and cell studies are never counted.

See all 113 studies →Hide the studies

Review Totals and Summary

Members Only6,065 reviews · 78% positive
6,065 reviews · Store.mayoclinic 3,197 · Unidentified retailer via Google 1,526 · Amazon 858 · Thorne 470 · Vitacost 14
78% positive2% neutral20% negative

Thorne Amino Complex in Lemon comes across as a well-regarded, effective powder, with taste the main point of disagreement. The stores carry about 1,342 ratings in total, and Thorne's own page shows 4.4 from 470 of them. **What buyers say it did for them:** Buyers mostly describe it as support for training and recovery. One says, "Our athlete uses it after intense training sessions and before training." Another notes "some changes after 1 month." A third finds it good "for recovery after any type of workout." Amazon's page summary calls it effective for reaching performance goals, with some people feeling less sore. **What they complain about:** Taste is the biggest complaint. One buyer found it "too strong and quite artificial" and said they got an allergy reaction even at half a sachet, though they couldn't tell which ingredient caused it. They stopped taking it. Amazon reviewers split sharply, with some calling the lemon flavor awful, and some report nausea. Amazon also tags odor as a negative. Shipping problems come up as well: one buyer received two shipments in one week and ended up with "2 unopened jars," and another found delivery slower than expected. **Taste, mixing and form:** Opinions differ. Some like it: "Takes great" and "Refreshing & Delicious Lemon flavor." Others find it too sweet and had to add "fresh lemon juice and extra water." Several say they prefer the berry flavor, and one says the opposite, liking lemon "much better than their berry flavor." The powder is described as fine but needing to be mixed well, and one buyer starts with warm water. Amazon reviewers disagree on dissolving: some say it dissolves well, others find particles left in the drink. Single-use packets and a travel option are praised for convenience. One reviewer called it "Wonderful for travel!" **Value for money:** Amazon's summary flags value as a negative theme, with some buyers finding $52.00 for thirty servings hard to justify. Other comments mention free shipping and good value, but they're less specific. **Who it suits and who it didn't:** It seems to suit active people who want something for before or after workouts, those who trust the Thorne brand ("We switched from another brand to Thorne as they are high quality"), and people who travel and want the packets. It suited less well anyone sensitive to strong or sweet artificial-tasting flavors, anyone who reacted badly to it, and buyers who care most about price or about a fully smooth mix. Some who tried lemon wished they had chosen berry. Other forms of this product appeared on some store pages, but only the powder is covered here.

Biohacker Summary

Members Only10 of 10 recommend it
10 of 10 biohackers on our panel recommend it

Leucine, the main ingredient, gets a mostly positive reception: seven of the ten panelists recommend it, mainly because it switches on muscle building, and one more is neutral on the related amino acid isoleucine. Doses given run from about 1 gram added to a meal, to 2 to 3 grams per meal for people under 40 and 3 to 4 grams for those over 40, up to 8 or 9 grams a day, and one panelist suggests pairing it with other essential amino acids or a small dose of whey. Several say it matters less if you already eat enough high quality animal protein, and one notes it tastes horrible. Three panelists raise cautions that leucine's growth signal could be pro-aging or linked to plaque buildup or disease, and one of them warns outright against high levels. Methionine and tryptophan are smaller ingredients in this product, and panelists mostly praise tryptophan for mood and sleep while a few advise keeping methionine low.

See all 9 biohackers →Hide the biohackers
  • Ben Greenfield · Leucine · recommends
    • 29 Oct 2026 · recommends · YouTube ↗
      Describes leucine as the 'ignition' that turns on the signal for muscle protein synthesis, and that a sufficient dose is needed to hit the dose response and then have other essential amino acids to maintain the signal.
    • 9 Jul 2026 · recommends · YouTube ↗
      States that leucine is the primary trigger for muscle protein synthesis and recommends an essential amino acid blend with about 40% leucine for maximum stimulation.
    • 15 Apr 2026 · recommends · X ↗
      Recommends pulsing with compounds like leucine for maintaining and building muscle and maximizing muscle protein synthesis.
    • 10 Mar 2026 · Methionine · neutral · X ↗
      A new study found that lowering methionine in the diet of mice significantly increased calorie burning and weight loss, matching the metabolic effects of cold exposure.
    • 29 Jan 2026 · Methionine · neutral · YouTube ↗
      States that methionine is needed for glutathione production, and glutathione needs triple as we age.
    • 29 Jan 2026 · Threonine · neutral · YouTube ↗
      Mentions threonine as an amino acid essential for gut health.
    • 17 Jan 2026 · Tryptophan · neutral · YouTube ↗
      Mentions tryptophan as a co-factor and raw material needed to make melatonin.
    • 11 Oct 2025 · Tryptophan · neutral · YouTube ↗
      Mentions that simple amino acids like tryptophan and phenylalanine are methylated into neurotransmitters.
    • 11 Oct 2025 · Phenylalanine · neutral · YouTube ↗
      Mentions that simple amino acids like tryptophan and phenylalanine are methylated into neurotransmitters.
    • 19 Jul 2025 · Tryptophan · recommends · YouTube ↗
      Recommends ensuring enough tryptophan in the diet to naturally support the body's melatonin production, as it is a precursor to serotonin and then melatonin.
    • 12 Jun 2025 · Tryptophan · neutral · YouTube ↗
      Mentions tryptophan as a supplement that aids in serotonin production, as suggested by a guest.
    • 20 Feb 2025 · recommends · YouTube ↗
      Recommends Dileucine as a next-generation supplement for muscle recovery and protein synthesis, stating it delivers 86% more leucine to muscles and triggers 60% more protein synthesis than regular leucine, especially when paired with exercise.
    • 28 Dec 2024 · uses · YouTube ↗
      Dave Pascoe mixes up a concoction of different protein powders, leucine, and L-citrulline as a pre-workout drink.
    • 12 Dec 2024 · neutral · Podcast ↗
      Discusses the role of leucine in boosting muscle protein synthesis on plant-based diets.
  • Dr. Eric Berg · Leucine · recommends
    • 22 Oct 2026 · recommends · Podcast ↗
      The amino acid leucine is important for muscle growth, but getting sufficient protein is just as essential for maintaining muscle mass.
    • 23 Oct 2026 · L-Lysine · recommends · YouTube ↗
      Recommends L-lysine because it competes with L-arginine, which the virus needs to reproduce, thus blocking the virus from getting arginine and starving it off.
    • 18 Oct 2026 · neutral · YouTube ↗
      Mentions that animal protein provides leucine, an amino acid beneficial for muscle building.
    • 23 Sep 2026 · recommends · Podcast ↗
      Recommends getting enough leucine, a key amino acid for muscle growth, to help prevent and correct muscle loss.
    • 3 Aug 2026 · Tryptophan · recommends · Facebook ↗
      Mentions that certain foods contain tryptophan, which is in many different proteins, walnuts, milk, wine, and coffee, but warns that wine and coffee may still keep one awake.
    • 22 Jul 2026 · neutral · Podcast ↗
      Explains that leucine is an essential amino acid that signals muscles to grow, and its requirements increase with age, making it important for maintaining muscle after menopause.
    • 23 Oct 2025 · neutral · YouTube ↗
      Mentions that eggs contain all essential amino acids, including leucine, which is a key amino acid for building muscle.
    • 2 Oct 2025 · neutral · YouTube ↗
      Notes that the amino acid leucine, found in animal protein, stimulates insulin.
    • 11 May 2025 · Tryptophan · neutral · YouTube ↗
      Mentions that the FDA banned tryptophan for a period after serious side effects were linked to a bad batch, and the ban was lifted after a med's patents expired.
    • 22 Mar 2025 · Methionine · neutral · YouTube ↗
      Identifies methionine as one of the two amino acids from which the majority of dietary sulfur is obtained.
    • 21 Oct 2024 · neutral · Podcast ↗
      Notes that red meat contains leucine, an amino acid that triggers the synthesis of muscle.
    • 14 Mar 2024 · Tryptophan · neutral · Podcast ↗
      Notes that Tryptophan can turn into vitamin B3, but the mechanism is not very efficient.
    • 12 Mar 2024 · Tryptophan · neutral · YouTube ↗
      Notes that tryptophan can convert to B3, but the conversion efficiency is very low, requiring 60 times the units of tryptophan for one unit of B3.
    • 22 Feb 2024 · Histidine · recommends · Podcast ↗
      Recommends the right amount of histidine in one's diet to promote healthy hair growth by helping to produce keratin and regulating copper and zinc levels.
  • Thomas DeLauer · Leucine · recommends
    • 19 Oct 2026 · recommends · YouTube ↗
      Identifies leucine as the primary trigger for the mtorc1 pathway, which is the master switch for muscle protein synthesis, and recommends 2 to 3 grams per meal for those under 40, and 3 to 4 grams for those over 40.
    • 25 Sep 2026 · neutral · Facebook ↗
      Explains that leucine is important for muscle, with beef, whey, milk, and sardines clearing the 2-3g leucine threshold per meal, and that the threshold increases with age.
    • 21 Sep 2026 · neutral · Facebook ↗
      States that leucine is what flips the switch for muscle protein synthesis, and that adding leucine and essential amino acids to a small dose of whey can match the effect of a full 25-gram dose of protein.
    • 9 Aug 2026 · Tryptophan · neutral · YouTube ↗
      Believes that having enough tryptophan get into the brain over the course of the day enables the capacity to produce melatonin at night.
    • 1 Jul 2026 · Tryptophan · recommends · YouTube ↗
      Recommends tryptophan before bed for sleep.
    • 6 Jun 2026 · neutral · YouTube ↗
      Notes that leucine, an important amino acid for muscle growth, activates mTOR signaling after exercise, triggering the first step in building new muscle, and that leucine plus carbs together have the strongest signaling effect.
    • 16 May 2026 · Tryptophan · neutral · YouTube ↗
      Discusses tryptophan being taken off the market in the early 90s due to a bad batch from one company that had neurotoxins, leading to a quality control issue and a temporary ban.
    • 28 Apr 2026 · Tryptophan · uses · YouTube ↗
      Takes 500 to 1,000 mg of tryptophan at night to help produce serotonin and melatonin, which are important for tilting towards a parasympathetic tone and relaxation.
    • 20 Mar 2026 · Tryptophan · uses · YouTube ↗
      Mentions taking a tryptophan supplement before sleep.
    • 24 Feb 2026 · recommends · YouTube ↗
      Recommends taking 3 to 5 grams of leucine with meals, especially for older individuals who may struggle to meet minimum protein requirements, as it can help preserve muscle and increase muscle protein synthesis.
    • 23 Dec 2025 · recommends · YouTube ↗
      Recommends protein sources that are high in leucine as a '401k of your fat burner' because they lead to more metabolically active lean tissue, especially for people dropping weight.
    • 18 Dec 2025 · Tryptophan · stopped · YouTube ↗
      Rates tryptophan as "foggy" for sleep, explaining that while it's a precursor to serotonin and melatonin, it needs to be taken by itself without other food to avoid competing with other amino acids for absorption. He states he oftentimes takes it, but lately has not been.
    • 26 Nov 2025 · recommends · YouTube ↗
      Explains that leucine skyrockets mTor and phosphorylates P7S6K, which is exactly what one wants to be activating, especially post-workout but throughout the day if trying to build muscle and recover.
    • 30 Aug 2025 · Isoleucine · neutral · YouTube ↗
      Mentions that some people believe avoiding isoleucine is key to the sugar diet, potentially increasing FGF-21.
  • Dr. Rhonda Patrick · Leucine · recommends
    • 30 Sep 2026 · recommends · YouTube ↗
      Notes that foods high in leucine are going to really support muscle protein synthesis.
    • 5 Dec 2024 · recommends · YouTube ↗
      Explains that Leucine is the critical signal driving robust activation of mTOR, which plays key roles in skeletal muscle growth by driving muscle protein synthesis and recovery, but also notes a study suggesting Leucine might activate mTOR in the vascular system, promoting plaque buildup.
    • 30 Jul 2024 · neutral · YouTube ↗
      Highlights that leucine is an amino acid with strong signaling properties, stimulating the mTOR pathway and setting off the anabolic cascade for muscle protein synthesis.
    • 3 Jul 2023 · neutral · YouTube ↗
      Mentions that leucine, a branched-chain amino acid, and other essential amino acids may be partially protective against declines in muscle mass, but not entirely effective against strength declines.
    • 6 Dec 2022 · neutral · YouTube ↗
      Discusses leucine as an amino acid that kick-starts the muscle-growth process, noting that 2 to 3 grams may be important for older individuals to kick-start that process, but does not recommend it as a supplement if consuming high-quality animal-based protein sources.
    • 29 Jun 2022 · warns · YouTube ↗
      Warns that leucine is extraordinarily bitter and requires food science to mask its taste. He also states that leucine supplementation should be a last resort, advocating for a food-first approach.
    • 28 Jan 2020 · Tryptophan · neutral · YouTube ↗
      Mentions that NAD can be synthesized in the body from dietary sources including the amino acid tryptophan, found in foods like salmon, spinach, and nuts.
    • 5 Aug 2019 · Tryptophan · neutral · YouTube ↗
      Dr. Patrick explains that tryptophan is a precursor for serotonin, a neurotransmitter important for mood and cognition, and exercise increases its availability to be transported into the brain to form serotonin.
    • Date not recorded · neutral · Website ↗
      Identifies leucine as a major activator of mTORC1, which is critical for muscle protein synthesis.
    • Date not recorded · neutral · Website ↗
      Notes that leucine is the highest affinity amino acid sensor for mTORC1, explaining why branched-chain amino acids, particularly leucine, are used to enhance muscle growth or prevent degradation during exercise. He believes 5 grams during a workout is probably not harmful.
    • Date not recorded · Tryptophan · neutral · Website ↗
      Notes that tryptophan gets transported into the brain to be converted into serotonin but competes with BCAAs for transport, which are preferentially transported.
    • Date not recorded · Tryptophan · neutral · Website ↗
      Explains that genes converting tryptophan to serotonin in the gut and brain contain a vitamin D response element that represses gut serotonin production and increases brain serotonin.
    • Date not recorded · Methionine · neutral · Website ↗
      Methionine, along with other amino acids, regulates IGF-1 levels.
    • Date not recorded · Methionine · neutral · Website ↗
      Notes that in aged mice, methionine had a Goldilocks range within a low-amino-acid diet, where too little increased frailty and a moderate amount preserved lean mass and improved metabolism.
  • Dr. Mark Hyman · Leucine · recommends
    • 10 Aug 2026 · recommends · YouTube ↗
      Dr. Mark Hyman, agreeing with the guest, highlights leucine as a primary amino acid important for muscle protein synthesis.
    • 14 Jan 2026 · neutral · YouTube ↗
      States that leucine is important for muscle health and is the rate-limiting amino acid for turning on the switch that starts muscle building.
    • 14 Jan 2026 · Methionine · neutral · YouTube ↗
      Notes that as people age, glutathione production goes down, and they might need three times more protein in methionine.
    • 27 Aug 2025 · Methionine · warns · YouTube ↗
      Notes concerns in the longevity camp about excessive methionine intake, especially if not balanced with glycine, which could theoretically impair longevity.
    • 25 Jun 2025 · recommends · YouTube ↗
      Recommends leucine, an amino acid, for making muscle.
    • 26 Feb 2025 · Tryptophan · recommends · YouTube ↗
      Recommends tryptophan as an essential neuro-nutrient and a precursor for serotonin, which repairs the hippocampus, noting that it can be ordered from Amazon.
    • 2 Oct 2024 · Tryptophan · warns · YouTube ↗
      States that restricting tryptophan is not the solution for long COVID, as low tryptophan is an effect of the condition, and simply adding more does not help, especially if it's being metabolized into poisonous quinolinic acid.
    • 13 Sep 2024 · Tryptophan · neutral · YouTube ↗
      Notes that tryptophan, a precursor to serotonin, can improve constipation in IBS-C by increasing intestinal transit time and motility, but high levels could worsen IBS-D.
    • 11 Sep 2024 · neutral · YouTube ↗
      Highlights leucine as an essential amino acid that is nearly highest in protein sources and acts as a unique amino acid for metabolic signaling, like a switch that turns on muscle building.
    • 11 Sep 2024 · Tryptophan · neutral · YouTube ↗
      States that tryptophan is necessary for serotonin production in the brain.
    • 11 Sep 2024 · Threonine · neutral · YouTube ↗
      Mentions threonine as an essential amino acid for mucin production in the gut.
    • 21 Aug 2024 · L-Lysine · recommends · YouTube ↗
      Recommends pairing high-dose IV vitamin C with L-lysine, an amino acid with an antiviral component, for viral reactivation.
    • 14 Aug 2024 · Tryptophan · neutral · YouTube ↗
      Mentions looking at tryptophan as an amino acid supplement.
    • 29 May 2024 · Phenylalanine · recommends · YouTube ↗
      Sometimes increases the dose of phenylalanine in conjunction with essential amino acids for depression.
  • Andrew Huberman · Leucine · recommends
    • 25 Jun 2026 · recommends · YouTube ↗
      Suggests that adding free leucine, perhaps one gram in a capsule with a normal meal, can significantly boost protein synthetic response, especially for plant-based individuals.
    • 6 Aug 2026 · Tryptophan · recommends · Podcast ↗
      Recommends tryptophan-rich foods to improve serotonin and mood.
    • 6 Aug 2026 · Tryptophan · recommends · YouTube ↗
      Notes that tryptophan is an amino acid precursor to serotonin synthesis and that many foods enriched in tryptophan can lead to net increases in serotonin, impacting feelings of well-being.
    • 30 Oct 2025 · warns · YouTube ↗
      Suggests that leucine, because it triggers cellular growth by activating the mTOR pathway, is actually pro-aging, similar to growth hormone and testosterone, offering immediate benefits at the expense of long-term health.
    • 23 Jun 2025 · Tryptophan · recommends · Podcast ↗
      Recommends tryptophan to improve mood and gut health, and for irritable bowel syndrome.
    • 23 Jun 2025 · Tryptophan · recommends · YouTube ↗
      Recommends ensuring sufficient levels of tryptophan in dietary intake, noting that turkey and dairy products are good sources, as it is a precursor to serotonin.
    • 25 Apr 2025 · neutral · YouTube ↗
      Andrew Huberman explains that leucine is an essential amino acid important for inducing muscle protein synthesis, and it is found in high levels in sources like whey protein, beef, chicken, and eggs.
    • 10 Apr 2025 · neutral · Podcast ↗
      Discusses leucine.
    • 12 Dec 2024 · Tryptophan · warns · YouTube ↗
      Tryptophan or anything that contains 5-HTP (serotonin or a precursor to serotonin) could disrupt the timing of REM sleep and slow wave sleep.
    • 7 Oct 2024 · Methionine · recommends · YouTube ↗
      Recommends methionine as a good methyl donor to help lower homocysteine levels and reduce cardiovascular risk.
    • 24 Jun 2024 · recommends · YouTube ↗
      States that leucine is uniquely stimulating to skeletal muscle and recommends consuming closer to 9 grams of leucine per day, which is two to three times the RDA, for optimal muscle health.
    • 18 Dec 2023 · warns · YouTube ↗
      Notes that leucine, isoleucine, and valine, which are branch chain amino acids, make insulin go up.
    • 18 Dec 2023 · Isoleucine · warns · YouTube ↗
      Notes that leucine, isoleucine, and valine, which are branch chain amino acids, make insulin go up.
    • 18 Dec 2023 · Valine · warns · YouTube ↗
      Notes that leucine, isoleucine, and valine, which are branch chain amino acids, make insulin go up.
  • Dave Asprey · Leucine · warns
    • 3 Feb 2026 · warns · YouTube ↗
      States that very low levels of leucine are probably promoting high levels of protection against aging and diseases, but also promoting frailty, and high levels of this amino acid could be a risk for developing a number of diseases.
    • 25 Jul 2026 · Tryptophan · recommends · YouTube ↗
      Recommends tryptophan, an amino acid from high-quality complete animal protein sources like turkey, as a raw material for NAD+ production.
    • 9 Jul 2026 · Tryptophan · neutral · YouTube ↗
      Recalls when tryptophan was taken out of health food stores due to a contaminated baby formula study, not because of tryptophan itself.
    • 30 May 2026 · Tryptophan · recommends · YouTube ↗
      Dave Asprey recommends tryptophan, an amino acid, as one of the two most important raw materials for NAD+ production, found in high-quality complete protein sources.
    • 16 Oct 2025 · Tryptophan · recommends · YouTube ↗
      Explains that modern farming practices have reduced tryptophan content in plants, and we need tryptophan to turn into serotonin to repair the hippocampus, melatonin, and DMT.
    • 5 Aug 2025 · Phenylalanine · neutral · YouTube ↗
      Mentions phenylalanine as a precursor and building block for dopamine, and that the brain synthesizes dopamine from precursors like phenylalanine.
    • 15 Apr 2025 · Tryptophan · neutral · YouTube ↗
      Mentions tryptophan as a compound that might be needed if there's a blockage in neurotransmitter pathways.
    • 6 Feb 2025 · Methionine · neutral · YouTube ↗
      States that if you are deficient in methionine, your gut motility is messed up, leading to consequences like irritable bowel syndrome.
    • 14 Jun 2024 · Tryptophan · warns · YouTube ↗
      States that excessive tryptophan is not good for you.
    • 23 May 2023 · recommends · YouTube ↗
      Recommends ensuring enough Leucine, specifically two and a half grams, to activate muscle protein synthesis, otherwise consumed protein may not be effective.
    • 25 Apr 2023 · neutral · YouTube ↗
      States that 2.5 grams of leucine are needed in a meal to activate mTOR and stimulate muscle synthesis.
    • 18 Apr 2023 · Methionine · recommends · YouTube ↗
      Recommends looking at methionine for chronic allergies, noting it is an amino acid often restricted on plant-based diets.
    • 2 Dec 2022 · Tryptophan · neutral · YouTube ↗
      Discusses tryptophan, an amino acid, and its theoretical role in raising mTOR and increasing cancer risk.
    • 2 Dec 2022 · Methionine · neutral · YouTube ↗
      Discusses methionine, an amino acid more common in animal protein, and its theoretical role in raising mTOR and increasing cancer risk.
  • Peter Attia · Leucine · recommends
    • 26 Sep 2025 · recommends · YouTube ↗
      States that leucine is critical for muscle protein synthesis and recommends around 8 or 9 grams a day for optimal muscle health.
    • 26 Sep 2025 · Threonine · neutral · YouTube ↗
      Mentions that threonine is important for mucin production in the gut.
    • 21 Sep 2025 · recommends · YouTube ↗
      Recommends two to three grams of leucine a day for muscle health, with optimal health probably around eight or nine grams.
    • 30 Aug 2024 · neutral · YouTube ↗
      Recounts a story where a vegan doctor chastised him for suggesting ingesting five grams of leucine during a workout due to its negative effect on mTOR and potential link to cancer, which Peter Attia found amusing.
    • 25 May 2024 · warns · YouTube ↗
      Warns that there is no benefit to supplementing leucine specifically if one is already consuming enough high-quality protein, and notes that leucine tastes horrible.
    • 27 Apr 2024 · Methionine · neutral · YouTube ↗
      Notes that many plant-derived proteins are low in methionine, and some meat alternatives are fortified with it.
    • 24 Apr 2024 · neutral · YouTube ↗
      Mentions that estimations suggest two to three grams of Leucine in a meal will induce a rapid increase in circulating Leucine, stimulating muscle protein synthesis.
    • 22 Apr 2024 · recommends · YouTube ↗
      Highlights that leucine content is an important factor in the anabolic response, and adding free leucine to casein can increase its anabolic effect.
    • 22 Apr 2024 · Methionine · recommends · YouTube ↗
      Recommends focusing on getting enough methionine, especially for plant-based patients, to ensure adequate amino acid intake for muscle protein synthesis.
    • 18 Apr 2024 · recommends · YouTube ↗
      Recommends tracking amino acids and ensuring 2 to 4 grams per serving of leucine for muscle mass.
    • 18 Apr 2024 · Methionine · recommends · YouTube ↗
      Recommends tracking amino acids and ensuring at least 1 gram of methionine per day for muscle mass.
    • 14 Mar 2024 · neutral · YouTube ↗
      Discusses experiments on Leucine and its effect on muscle protein turnover and fat metabolism.
    • 9 Mar 2024 · neutral · YouTube ↗
      Mentions Leucine as one of the four signals that regulate mTOR, which is involved in protein synthesis.
    • 25 Sep 2023 · neutral · YouTube ↗
      Explains that leucine binds to a protein called sestrin, which acts as its receptor, and the crystal structure shows how leucine is nestled in a small pocket, making it difficult to mimic its anabolic effects with other molecules.
  • Siim Land · Isoleucine · neutral
    • 18 Aug 2024 · neutral · YouTube ↗
      Notes that his isoleucine levels went down because he is taking leucine, which is a branch chain amino acid.
    • 19 Oct 2026 · Methionine · recommends · YouTube ↗
      Recommends keeping methionine intake slightly lower to support autophagy.
    • 13 Oct 2026 · Methionine · uses · Instagram ↗
      Lowered his methionine intake as part of an amino acid strategy.
    • 21 Aug 2026 · Methionine · warns · Instagram ↗
      States that methionine in excess may accelerate aging.
    • 30 Jul 2026 · Methionine · uses · Instagram ↗
      Lowered his methionine intake to reduce visceral fat.
    • 28 Jul 2026 · Methionine · uses · X ↗
      Reduced visceral fat by reducing methionine.
    • 27 Jun 2026 · Methionine · neutral · Podcast ↗
      Discusses the methionine and glycine ratio from animal protein.
    • 29 Apr 2026 · Methionine · warns · YouTube ↗
      Explains that too much methionine accelerates aging and shortens lifespan, and also appears to promote visceral fat gain.
    • 4 Feb 2026 · Methionine · recommends · YouTube ↗
      To get to the 10th percentile of visceral fat and lower, Siim Land recommends reducing methionine intake.
    • 10 Sep 2025 · Methionine · warns · YouTube ↗
      Warns that methionine, an amino acid high in animal protein, has been seen to shorten lifespan in animals, and most people eat too much methionine without enough glycine.
    • 29 Aug 2025 · Methionine · warns · YouTube ↗
      Notes that in animal studies, methionine excess is associated with shorter lifespan and high methionine intake drives aging or shortens maximum lifespan.
    • 29 Nov 2024 · Phenylalanine · neutral · YouTube ↗
      Notes that L-phenylalanine can boost dopamine, with many articles available on PubMed.
    • 18 Aug 2024 · Leucine · uses · YouTube ↗
      Despite high protein and whey intake, Siim Land's leucine levels remain low, hovering around 70, which he attributes to increased muscle mass and the body fighting infection.
    • 18 Aug 2024 · Phenylalanine · neutral · YouTube ↗
      Noticed that his phenylalanine levels go up if he generally eats more protein, as it is not heavily utilized by exercise.

RAL Summary

Members OnlyTier 3 for Muscle and Strength

The tier rests on a misreading of the isoleucine evidence: 26 of 54 studies is under half, not 83% of people, no study gave a percent improved, isoleucine was never tested alone, and the larger branched-chain amino acid trials mostly found no muscle gain. So it is graded Tier 3, lower than the rules alone gave.

Where the evidence disagrees: 32 of the 113 human studies found no effect.

More Details

Members OnlyBody systems · Combine with · Possible side effects

Body systems: Musculoskeletal system

Combine with: For muscle building and recovery, pair with the remaining essential amino acids (or a complete protein such as whey or pea/rice blend), valine if using an isolated BCAA, creatine monohydrate (3-5 g/day) for strength and lean mass, and vitamin D3 with magnesium for muscle function and recovery. Omega-3 fish oil can help reduce exercise-related inflammation. If the real goal is weight management for men, add targeted options such as protein for satiety, fiber (glucomannan or psyllium), green tea extract (EGCG), berberine or chromium for glucose support, and CLA, alongside a calorie deficit and resistance training, where this amino product can help preserve muscle.

Possible side effects: Some reviewers report nausea, and one reported an allergy-like reaction and stopped. The studies given report no side effects.

Supplement Facts

L-Leucine 1.25 g · L-Lysine 650 mg · L-Isoleucine 625 mg
Supplement Facts
Serving Size One Scoop (7.7 g)
Servings Per Container 30
Amount Per Serving% Daily Value
Calories25
Total Carbohydrate1 g
L-Leucine1.25 g†
L-Lysine650 mg†
L-Isoleucine625 mg†
L-Valine625 mg†
L-Threonine350 mg†
L-Histidine150 mg†
L-Cystine150 mg†
L-Phenylalanine100 mg†
L-Methionine50 mg†
L-Tyrosine30 mg†
L-Tryptophan20 mg†
† Daily Value not established.

Other ingredients: Flavor, Citric Acid, Rebaudioside A (from stevia), Turmeric Powder.

Directions: Mix 1 scoop with at least 8 ounces of water one to two times daily or as recommended by your health-care practitioner.

Label source: Reverseagelab · Report a label change

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Graded November 6, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.