Tyler Sellers
Published by Tyler Sellers
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: February 14, 2021

Taking L-carnitine is something that many of my clients wish they had done earlier, especially those that have aggressive goals for weight loss or muscle building.

The essential amino acid has been proven to play a key role in exercise performance and faster recoveries.

But you have to be careful with the types and quality you’re taking.

Unfortunately, there are plenty of products that won’t do much for your body.

So, we spent a few months working with different types of clients to come up with this list of the best L-carnitine supplements.

Our Top L-Carnitine Supplements

1 - Transparent Labs Fat Burner Stim-Free (Editor's Choice)

Transparent Labs Fat Burner Stim-Free

This fat burning supplement from Transparent Labs is the one we favor most because it avoids the use of stimulants.

That means you may be able to use it later in the day without risking a restless night.

The 750 mg per serving should also suit the majority of athletes, as stronger doses might produce some side effects.

  • Dosage: 750 mg
  • The provided dose should work well for most athletes
  • Includes other ingredients that may help with burning fat into energy
  • Could provide a vitamin B12 boost as well
  • Good bulk-discounts available
  • Free shipping is only available on bulk orders

The only minor downside we’d highlight is that you only get free shipping on the bulk orders, but it’s worth it.

2 - ProSupps L-Carnitine Supplement

ProSupps L-Carnitine Supplement

Some professional athletes that we’ve worked with have identified this as one of the strongest products available.

They also mentioned that it seemed to help them achieve more defined abs, which is an area where a lot of people tend to struggle with body fat.

We also found that the flavor seems pleasant and doesn’t tend to leave an aftertaste.

  • Dosage: 3,000 mg
  • One of the stronger options available to boost L-carnitine levels
  • Many positive reviews about the flavor
  • Should help you burn fat from stubborn areas
  • You may need to start with a smaller dose to avoid negative effects

Just keep in mind that if you’re starting to take L-carnitine, then this might be too strong.

3 - NOW Sports Liquid L-Carnitine

NOW Sports Liquid L-Carnitine

Liquid L-Carnitine may be a great choice if you need to adjust your dosage for specific training sessions.

Many bodybuilders will adjust the intensity of their workouts, especially during a bulking phase. That’s when taking a high dose may give you the right energy boost.

NOW sports claims that their formula is one of the fastest to absorb, and we’ve seen comments online that this seems to be true.

  • Dosage: 1,000 mg
  • Comes in a liquid form to make a precise dosage measurement
  • Claims to be the fastest to absorb and increase energy levels
  • Tested for banned substances making it suitable for professional athletes
  • The flavor is very strong, so you may want to water it down

The only thing we noted is that it has an intense taste, so you may want to water it down a bit.

4 - MusclePharm Essentials Carnitine

MusclePharm Essentials Carnitine

The company claims to have the most powerful blend of propionyl L-carnitine, acetyl L-carnitine, and L-carnitine-L-tartrate. Apparently, this should help produce energy more efficiently.

Our clients tend to agree, and they feel they are getting better pumps after taking this L-carnitine supplement [1].

It might also be a good choice for competitive athletes who need to make sure their nutrition supplements don’t contain any banned substances.

  • Dosage: 1,000 mg
  • Uses a unique combination of different forms of L-carnitine
  • Positive comments about boosted nitric oxide levels for better pumps
  • Tested for banned substances which may be important for professional athletes
  • Some people have reported minor stomach issues

We did notice a few online reviews where people mentioned feeling a bit bloated a short time after taking it.

5 - BRI L-Carnitine

BRI L-Carnitine

This is another product that people like because the company has kept the formula as simple as possible.

Who needs unnecessary fillers and allergens, right?

There are also no stimulants which some companies include to make it seem like you’re getting an energy boost, rather than actually transforming fat into energy.

The dose also seems to have hit a sweet spot for most athletes, as it shouldn't result in any negative health effects.

  • Dosage: 1,000 mg
  • Straightforward formula with no fillers or allergens
  • Positive comments from bodybuilders going through a cutting phase
  • Avoids stimulants, so the energy you get is real
  • The capsules might be a bit large for some users

The only thing we noted is that some people have struggled with the size of the capsules.

6 - Life Extension Optimized Carnitine Capsules

Life Extension Optimized Carnitine Capsules

The last one of our recommended L-carnitine supplements comes from Life Extension, which seems to be a good option for fast absorption.

We heard from several people that they take it shortly before a training session and don’t have to wait a long time to feel it kicking in.

And if it doesn’t work for you, then you could get your money back as well.

  • Dosage: 1,100 mg
  • Claims to be optimized for faster absorption
  • Many comments about the positive workout performance
  • Comes with a money-back guarantee for peace of mind
  • The supplement capsules are a bit on the large side

The only thing we found is that the capsules are quite large compared to other products.

7 - BulkSupplements AlCar HCL

BulkSupplements AlCar HCL

BulkSupplements has chosen to focus on the ALCAR type of carnitine, which apparently may help to produce energy for your muscles and brain as well [1].

This is something that many athletes underestimate, as gaining some focus and motivation may help you to get through a tough workout session more easily.

Our clients like it as they are able to mix the powder into their pre-workout supplements as well.

  • Dosage: 600 mg
  • Uses acetyl L-carnitine for increased production of energy
  • Comes in a powder form to allow precise doses for your needs
  • Positive feedback about boosted brain energy
  • Measuring the small amount of powder can be difficult

While the powder makes it convenient, you may want to get some sensitive scales to measure precise amounts.

8 - MuscleTech L-Carnitine

MuscleTech L-Carnitine

This L-carnitine supplement is based on L-carnitine tartrate, which some believe to be the faster-acting type to take.

It might be a lower dose, but many reviewers have mentioned that it’s strong enough as it helps them avoid premature fatigue during training.

We also heard from clients who find they have a better recovery phase on the days they take it.

  • Dosage: 500 mg
  • Uses L-carnitine L-tartrate as a rapid-acting formula
  • Doesn’t have any stimulants making it suitable for later in the day
  • Online reviews highlight it might be helping with muscle recovery
  • Might not be strong enough for performance athletes

Now, if you’re doing some serious bodybuilding, then you probably need to look at stronger products.

9 - Nutricost Acetyl L-Carnitine

Nutricost Acetyl L-Carnitine

Here’s another supplement that comes in a powder form, which should allow you to get the dosage right for your muscle building and cutting phases.

Having that flexibility might improve your endurance, but it would also help you to not waste any of the product.

  • Dosage: 1,000 mg
  • Comes in powdered form to mix in with shakes and smoothies
  • Claims to contain acetyl L-carnitine for better energy production
  • 3rd party tested for purity and quality
  • The flavors seem to be very sour

We did notice that the flavor is very sour, so you may want to mix it with a shake or smoothie.

10 - Optimum Nutrition L-Carnitine

Optimum Nutrition L-Carnitine

Optimum Nutrition L-Carnitine is a product with a lower dose than we’d often recommend to people who don’t need a max strength product.

No point wasting money, right?

What some of our weight management clients have mentioned is that on the days that they consume this product, it made them feel less hungry.

And that should mean more stable blood sugar levels and healthy weight management.

  • Dosage: 500 mg
  • Some users have commented about a reduction in food cravings
  • Capsules are small enough to easily swallow
  • Has a simple formula with no added fillers or allergens
  • The dose might not be strong enough for serious bodybuilding

Just keep in mind that if you’re looking for serious pumps and endurance, this might not be the right choice for you.

Buyer’s Guide

credit card and laptop

1 - Check Out The Dosage And Type

While there isn’t a recommended amount of L-carnitine per day, it’s important to look at how much each product contains per serving.

A good average is about 750 mg, but you might get away with less depending on the different types of L-carnitine used.

What do I mean?

Some evidence suggests that L-carnitine tartrate might work for faster muscle recovery, while propionyl-L-carnitine might provide better pumps.

2 - Look For Other Ingredients

l-carnitine natural ingredients

You’ll find that some of these supplements only focus on L-carnitine with no other ingredients.

That’s great for stacking where you don’t want to end up with overlapping ingredients.

But many people might boost their health and wellness with supplements that also have some vitamins and other amino acids per serving.

It’s definitely something to factor into your price comparison.


3 - Compare The Price Tags

What I usually do is work out how much I need to take per day, and then calculate the price for that dosage on each product.

This is important if you need a very precise amount.

But most people will probably be fine with a dose of about 750 mg.

Now, I wouldn’t recommend just going for the cheapest product. These often use processing and refining techniques that could break down the amino acids.

As a result, you might get a lot less than is advertised.

Benefits Of L-Carnitine

1 - Muscle Recovery

muscle recovery

I spent some time reading about a study that revealed that L-carnitine might increase blood flow to muscle tissue [2].

Every muscle in the human body requires nutrients and oxygen, and if you can get more blood into every muscle fiber, then it would make sense that any damage from exercise could be repaired faster.

And if you can speed up your recovery period, then you should be able to perform better in your next exercise session.

That’s an important factor if you want to speed up your progress towards your goals.


“L-Carnitine assists in being better at fuel use, whether you are training or not. However, the best performance outcome does appear to be aiding in day-to-day recovery, especially from weight-training and sessions damaging to muscle, such as intense running.”


- Joe Beer, Health and Fitness Writer.

2 - Reduce Fatigue

reduce fatigue

Some studies also suggest that carnitine helps to reduce fatigue [3].

Now, to get the full benefit of this, you might need to experiment a bit with your intake timing.

What does that mean?

So, there are two things you’d need to know. First of all, you’d need to figure out how long it takes for you to notice that your supplement is starting to work.

This could be 10 minutes or 4 minutes.

The other thing you need to know is at what stage of your workout you usually start feeling your endurance levels drop. Maybe it’s 30 minutes into a session.

What you then want to do is take the carnitine supplement at a time when it would provide the best results to combat fatigue.

3 - Boost Endurance

Carnitine can help increase exercise performance when taken in a high enough dose.

That doesn’t mean you should just take a huge amount, as your body might react negatively.

The way it works is by increasing blood circulation and delivering the right types of fatty acids into your muscle tissue. 

That’s where it’s transformed into cell energy, and the more energy you have in your muscle tissue, the better you’ll be able to keep up the reps with more intense sets.

4 - Weight Loss

weight loss

Weight loss can be quite a challenge for people trying to get fit and for bodybuilders who need to trigger some fat loss in a cutting phase.

If you use L-carnitine on your exercise days, then it should help you to burn away more fat than just exercise would achieve.

It’s not a magic pill to watch the pounds drop off while you sit on the couch.

But combining the right diet with quality supplements and a solid training routine should help you achieve your weight goals more quickly.

If you want to lose weight faster, we have created a list of the best fat burners for men and the best fat burners for women.

“This valuable little molecule has been a staple in the bodybuilding and brain-hacking communities for years now, thanks to its ability to help you lose weight and power up your brain.”


- Spencer Brooks, Nutrition Writer at Bulletproof.


Is L-Carnitine Bad for Your Heart?

No, L-carnitine isn’t bad for your heart; in fact, some studies have even shown that the opposite could be the case. Evidence suggests that it could play a role in reducing the risk of heart arrhythmia as well as developing angina.

Which Is Better Acetyl L-Carnitine or L Carnitine?

Some scientists believe that acetyl L-carnitine is better for the human body. It’s believed to be easier for your stomach to absorb, which would make it the faster-acting form. Also, some research suggests that it crosses the blood-brain barrier more easily.

Does L-Carnitine Cause Hair Loss?

No, L-carnitine doesn’t cause hair loss. There’s actually some evidence that it could increase the blood supply to hair follicles and deliver more nutrients to increase hair growth. It’s one side effect that many users have reported after several weeks of use.

Does L-Carnitine Have Side Effects?

Yes, L-carnitine can have side effects in rare instances and with heavy doses. These might include stomach cramps, nausea, heartburn, and diarrhea. But in most cases, these symptoms will disappear as soon as you reduce the dose or stop taking it altogether.

Is L-Carnitine Good for Weight Loss?

Yes, L-carnitine is good for weight loss. It plays a key role in transforming stored body fat into the type of energy that different cells in your body need. That doesn't make it a miracle pill for dealing with weight issues, but combined with a good diet and exercise routine, it should help.

Can You Take L-Carnitine on an Empty Stomach?

Yes, you can take L-carnitine on an empty stomach. Many dietitians would recommend this approach as it seems to be easier for your stomach to digest and absorb the supplement. Just check for any signs of negative effects.

Which L-Carnitine Supplement Should You Order?

Out of all the L-carnitine supplements we tested out with clients, we got the best response on Transparent Labs. This is mainly down to the fact that it delivers more than just L-carnitine, which should help you with weight management.

It’s also the one supplement that gave us the best results during training and recovery phases.

Order yours today and then report back to us how much it changed your training days.

Transparent Labs Fat Burner Stim-Free

Transparent Labs Fat Burner Stim-Free

Our #1 Recommendation

  • The provided dose should work well for most athletes
  • Includes other ingredients that may help with burning fat into energy
  • Could provide a vitamin B12 boost as well
  • Good bulk-discounts available
  • Get the BEST PRICE until the end of April
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About the author

  • I really like this stuff! To be honest it is my first. I was hesitant about taking this because I’m not a pill person but hey there’s a bikini with my name on it that I will be in!! I am losing and shedding those extra curves on these! I don’t have any issues with side effects, my cravings at night are not as intense as prior to taking this pill and I sleep a whole lot better than ever! Thank you Isaac for the thoughts.

  • After a few days of using this product, I can say that it works pretty well! If it were not for the accidental access to your blog, Isaac, I wouldn’t have known about these products. To put things in perspective, I haven’t been having as many cravings, whereas I constantly have something in my mouth before. And I can have something small in the morning like a small bowl of fruit or two hard boiled eggs and feel completely satisfied for hours! I sleep so well with this stuff also. I have a crazy schedule and stress eating is so damn real for me, but this has truly helped and I am so thankful for that!

  • I’ve probably use this product for about 8wks now after having introduced to it in Isaac’s post. And I am pretty much done with my 1st bottle. I have noticed some changes in my weight. And let’s be honest, I could be more active and gym involved and actually could have lost some more! But “stay at home dad” you know how that goes in this society. I have lost about 5 pounds and honestly I take 1 pill at night or sometimes 2. I’m not really sure on the directions because it says 1 thing on the bottle and another on here. I don’t notice any changes in my sleep. I do have a bad case of insomnia so I just take a melatonin along with it. The pills aren’t too big and easy to swallow. Glad to discover this!

  • So it has been a while now after purchasing this with the blessing of Isaac’s words and this is what I experienced so far. I sleep like a baby and wake up refreshed not sluggish. Take 1 hour before I want to fall asleep. I have experienced weight loss, but I am following a nutrition plan to couple this with and start out walking 4 miles every morning during weekdays, combined with a complete exercise gears. After work out and by the end of day I have not noticed I walked 8000-10000 steps! I have lung complications and a mild case of asthma. So I need to take inhaled steroids. I have tried everything and had considered surgery. These were my last ditch efforts as I could never lose more than 5 pounds total which would go up and down and fluctuate so bad. I have tried other ways to reduce my extra curves and you name it, even a medical weight loss plan. All super strict following and exercising. Nothing more than 5 pounds either way. I am not a doctor, but this definitely works for my body! Love this product and am reordering once I am out of stock. Will continue with the combo till I hit my goal!! Hope to keep you posted.

  • I’ve only been on these 4 days. It took me a while to purchase as I was having doubts, until I stumbled upon Isaac’s post. I’m not sure about losing weight yet but I have noticed that I’m not bloated in the morning and my stomach has been flatter. It’s not like a diuretic or anything. I’m not sure how it works. My sleep! However, it has never been this way ever since I can remember. It has been amazing! I have so much trouble sleeping in past. I would sometimes take up sleeping pills at night to help me sleep but to no avail. But even then I would wake up 2 or 3 hours later. With this, I take it and I am passed out ALL night! Like magic! I do not wake up groggy either as I did with my previous pills. They are easy to swallow, and have no taste. I am now a fan of your for sure! Hope to learn more from you Isaac.

  • First, I would like to say thank you Isaac for taking the effort in sharing your thoughts. Okay. This product works great. But first, let’s be honest with ourselves guys, there is NO such thing as MAGIC PILLS. Nothing will work for you if you don’t make a slight lifestyle adjustment. That’s the reality. I have been taking these pills for the last 3 months and I definitely love it. It started a little slow, because it takes time for your body to adjust, but ever since my sleep has been amazing. To make things a whole lot better, I have lost 10 pounds! I cannot believe it. It has helped me with my sleep quality, bloating, gas problems and has erased my constipation issues. I haven’t experienced any negative side effects per se so I hope you guys have not as well. I suggest that you eat a light dinner early and take the pill about an hour before bed. Be patient and watch the magic unfold. To better sleep for us!

  • A little background about myself, I am a heavy eater at night because I work a graveyard shift. That is not helping my weight loss journey at all that I could only have so much self-discipline. Before, I was starving come late nights and I would cave on my way home. Junk food is all that’s open that late so I would cave and go to sleep with a fat burger in my gut when I went to bed. I decided to give this a try since it had great words from you Sir Isaac. By the way, the first night I took it, it was a wonderful surprise. I haven’t had success with these types of pills before! Well, I took it the break before I left and I was NOT hungry and because I didn’t feel starved half to death. I was able to drive right past jack in the box and go straight home crawled in bed and had no issue falling asleep like I normally do! Holy! I feel like this is going to be the extra push I need to stick to my diet plan. Even when I woke up 6 hours after falling asleep, I still wasn’t hungry even though I’d normally want to rummage through my food for a snack. The desire just wasn’t there anymore and it was a really nice feeling. I am going to report back in the future to see if it added an extra boost in reducing these unwanted fat because it certainly helps everywhere else. It’s the first pill that seems to do just as I want it. Thank you.

  • I have only used this product twice when I first read it here in Isaac’s, but they don’t stink like most pills. It’s also a 2-month supply. I have noticed my late night snacking has decreased. I usually take a prescription sleep aid that I will be taking with it tonight. I was hoping I would be able to substitute the product for my prescription. I will have to find out if it does help me in this matter. With all the positive thoughts from you Sir Robertson, I am excited about the results.

  • I have been using these pills for about a month now since I found it out here, and I have to say I have never been satisfied with the results before from using a product! Due to my work schedule, I have to do my strenuous physical activities in the evening, which would often “work me up” and make it hard for me to go to bed. These pills help me relax and help me sleep better; not to mention, the extra boost to my metabolism does help. Since I have started using these pills in early this year, along with making sure to eat my veggies every day and exercise moderately, I have lost almost 15 pounds. Will definitely be buying these again once I ran out of stocks. Keep informing us Isaac.

  • I have been a loyal reader of Sir Isaac and whenever I want to go through a change in my life, I often seek his posts for advice. Now, I bought this product because again, I want to change my life. Before, I was unable to fall asleep and stay asleep, lose weight and feel rested. After taking this product the first night, it didn’t make me feel tired. So I thought it’s not going to work, but the next thing I know, my alarm was going off. I actually slept the entire night! Amazing!! I don’t wake up feeling groggy or tired like other products I have used before! No restlessness and I’m sleeping every night like a baby! This will now be a part of my night regime from now on. I will be getting this again soon. I am still your fan Isaac. Thanks!

  • This is very helpful post. I visit this website for any kind weight loss tips. I really appreciate the products that they recommend. You are doing very good job.