Cellucor CLK Review – As Good as the Mighty Super HD?

Posted on March 6th, 2015 By Allie Lewis in Fat Burner Reviews Read Time: 12 mins.

Recently updated on September 26th, 2022 at 09:54 pm

Today’s review is on CLK Fourth Generation Fat Burner by Cellucor. I’ve been getting asked about his product for several weeks now and figured it’s time to give this product an official BPW review! In this in depth analysis I’ll tell you about the ingredients, side effects, and ultimately if this product works. I’ll finish with an overall assessment of the product’s value to help you decide if this is the right fat burner for you.


CLK is in a very unique product category. It’s certainly a fat burner- but you might be asking what the difference is between CLK and Super HD? Super HD is the smash-hit diet pill from Cellucor and is the reigning champion of our very own BPW Top Fat Burner for Women. You can see my Super HD review here. With this years rankings upcoming, it will be interesting to see if CLK can claim a spot in the top ten. But getting back on track- what’s the difference between it, and Super HD. The difference is that CLK is a stimulant free, or ‘stim-free’ fat burning diet pill. This is incredibly rare in the category because of how effective caffeine can be at burning fat. That’s what makes it the most popular ingredient in diet pills- it works, and users can ‘feel it’ working through the energized feeling it provides. So can CLK hold it’s own in the caffeinated world? Let me tell you about my experience with it. 

Cellucor CLK Effects & Benefits Grade: 8.9

I went into my two-week trial with CLK with frankly a closed mind. I’ve always been a believer in the caffeinated products, and basically a doubter in anything without it. Layer in the fact that I’m really trying to cut down for my second figure competition, and I honestly wasn’t super pumped to give a stir-free product a try. I bought a jar of CLK (4th Generation) and started taking 3 softgels in the morning and three in the afternoon as instructed. The nice thing about taking a stim-free diet pill is that you don’t have to worry about over-caffeinating yourself. That meant I could keep taking my pre workouts – which as you know I’ve been doing daily in preparation for this years BPW Top Pre Workout of 2015! Someone’s got to review the nominees, right? Right. So anyways- the first time I took my three softgel serving, I felt absolutely nothing. And you know what? I never ‘felt’ anything from ANY of the times I took my CLK softgels. You won’t either. Nobody will. That’s the weird part of taking the stir-free products. You’ve got to judge it’s effectiveness purely by what you see in the mirror every day. And to be honest- I kind of like that aspect of this product. It doesn’t depend on a false feeling of effectiveness when the real effects are actually not seen right away. I worked out like a demon for those two weeks, and what I found was that CLK actually did help in some noticeable ways. 

The first thing I noticed when taking CLK was that my vascularity improved. It wasn’t like night and day- and since I’m only about 7 lbs. from being my leanest figure- of course nothing was going to be night and day. But when I woke up in the mornings towards the end of the second week- I noticed the veins in my upper quads and in my lower abs were definitely more pronounced. Now I’ve definitely been ramping up my ab workouts to bring up that part of my figure, but I think CLK really did play a role in this.

The other thing I noticed with CLK was that some of my striations became more noticeable. Don’t get me wrong I’m not one of those girls that have the crazy definition everywhere on their body, but I do have some places, mostly in my upper abs and chest that I can get some good musculature. I started to notice those areas would really ‘flutter’ when flexing or working them hard in the gym. CLK helps strengthen your stronger areas of definition in my experience.

The third and last effect that CLK provides is just general weight-loss. Like I said, I’ve deliberately been trying to drop about 4 lbs, and by the end of the second week I had already dropped 3 of the 4 lbs! Pretty awesome. I should footnote that this was not just water-weight either. There are no diuretic ingredients in CLK so this was very authentic weigh-ins. 

So speaking of the ingredients, let’s take a peek under the hood and talk about the supplement facts panel and what’s actually in these diet pills. 

CLK Forumla Grade: 9.0

I’m giving CLK an A on their formula, which you know I don’t do very often in diet pill reviews. But once again, Cellucor proved that they’ve got the smartest guys in the room formulating their products. This isn’t just another cookie-cutter fat burner with caffeine and synephrine and capsicum. CLK is a play on the popular product title ‘CLA’ which stands for ‘Conjuagated Lineolic Acid’ – a fatty acid found in red meat that has long been purported to have fat burning properties- and that this product still does contain. But anyways- Cellucor cleverly swapped out the ‘A’ for a ‘K’ which has always represented the ‘Ketones’ (Raspberry Ketones) in this product. Cellucor has overhauled this product a few times, but it has always contained the Ketones. Here are the four ingredients in CLK: 

  1. Raspberry Ketones: As mentioned, this has long been the feature ingredient. However, since it’s effectiveness has been called into question as of late, it seems Cellucor has made the story less about this aromatic ingredient and more about the others. 
  2. L-Carnitine L-Tartarate: LCLT will always have a special place in my heart and is in my opinion one of the most powerful dietary supplements that you can use today. It benefits you in so many more ways than just fat oxidation- from muscle recovery and growth to bone health to skin and hair support- any formula that has LCLT is going to get a good grade in my reviews.
  3. SlimPro: This is the newcomer to the CLK formula, and to be quite honest I had never been exposed to it before this product. It is the protein hydroslates of Blue Whiting (Micromesistius Poutassou). Say that ten time fast! Or even type it. LOL. So this is actually a fish protein that you are getting along with your CLA. Yikes. I’m thankful one of the softgels never broke open in my mouth! Apparently Slimpro works by increasing CCK and GLP-1, which essentially tell your brain that you aren’t hungry. I don’t know that my appetite was significantly blunted by this product, but it’s at least interesting to learn about this addition to the formula.
  4. CLA: Of course CLK does still contain Conjugated Lineolic Acid as one of the four feature ingredients.

CLK Side Effects: None

I did not experience any side effects while taking Cellucor CLK. 

CLK Packaging Grade: 9.5

Ok of course I have to finish things off with an overview of Cellucor CLK packaging. Now as you know I’m a fan of Cellucor’s. And that affection absolutely extends through to their design team. This is a company that, in my opinion, has made a name for themselves by differentiating their packages from anything else on the shelf. I mean, nobody had ever seen a CHROME pre workout on the shelf before. It was brilliant back then, and it continues to be brilliant now. CLK features the signature Cellucor Chrome series look, which has actually been updated just in the last few months as part of the G4 (4th Generation). The package now has more text and information on the front panel, along with a more subdued finish overall (still chrome in my opinion though). Their is also more bold outline detail that work to frame the information more clearly. I like that CLK uses a reddish tint to not only represent fat burning as a whole but also to represent the raspberry ketone. In fact the red I would describe as ‘raspberry red’! Great job as always on the packaging, Cellucor. 

Cellucor CLK Value and Final Score: 9.3


CLK scores highly again from me with their stimulant-free fat burner- CLK. I’ve reviewed tons and tons of fat burners in my day, but as the very first stim-free product that I’ve done, I was thoroughly impressed. I love that you don’t feel all hyper and jittery and then pretend that you’re fat burner is ‘kicking-in’ and doing it’s job. No. You know CLK works because you literally can see the effects come to life in the mirror every day. I’m totally in love with this product and would endorse it 100% as a safe and effective fat burner. Hats off once again to Cellucor for their work with CLK. 

Allie Lewis

By Allie Lewis

Hi, my name is Allie and reviewing products is my hobby. I am passionate about being fit and active, so making a blog about my experience with different products that help me stay healthy made sense to me. Please contact me at any time if you would like to guest post or advertise on-site.