Tyler Sellers
Published by Tyler Sellers
Fact checked by Donald Christman, BHSc FACT CHECKED

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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • Claims to be optimized for faster absorption
  • Many comments about the positive workout performance
  • Comes with a money-back guarantee for peace of mind
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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
Pros
  • 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
Cons
  • 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.

Related:

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.

Related:

“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.

FAQs

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 October
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