Olympus Labs K1ngs Slayer: A Natural Anabolic with an Appetite for Destruction

Olympus Labs K1ngs Slayer

With one new muscle-building ingredient and three appetite-boosters, this supplement is sure to have you slaying -in both the gym and the kitchen!

It’s been a long time since we’ve covered Olympus Labs, but after countless requests on our YouTube channel and a look at their latest product labels, we’ve decided to dive back in. We’ll be giving their monster pre workout (Re1gn) a shot at the title, but we’ve been most impressed by the new ingredients they’ve been bringing to market. What’s in the product below is a perfect example.

Olympus Labs is no stranger to muscle-building supplement. But you may be a stranger to the natural ingredients in this one, the aggressively-named K1ngs Slayer. Today, it goes toe-to-toe with PricePlow’s judgement. There’s just four ingredients, but you may have never heard of a single one of them. You know that right there perks our ears up, since we’re always down to research new stuff.

Hardgainer? Light eater? Not anymore. Get ready to get Ghrelin going:

The long story short is that we have one ‘new’ anabolic ingredient backed up by three ghrelin-boosters that should seriously ramp up appetite, IGF-1, and nutrient uptake. We’ve used one of these ingredients already and it’s the real deal.

But do the rest of the ingredients deliver what the product promises? Time to find out, but first check the prices on PricePlow and sign up for our Olympus Labs news alerts, since we have a ton more research coming:

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The Premise: What does it take to slay a king?

Olympus Labs Or1gin K1ngs Slayer

Old meet new. Olympus Labs took what they learned in Or1gin and ramped it up to the next level in K1NGS SLAYER!

The biggest change to the supplement industry in the 2010’s are informed consumers. Lifters know what works, with far easier access to full-text research papers surrounding everything, including supplement ingredients. Any kid with a phone can fact-check your claims, so companies have had to get their game up to stay relevant. Olympus Labs has been at the cutting edge of this new industry frontier, with natural ingredients many aren’t going to find on mainstream or even “expert” websites. All of this introduction is to frame our high expectations for products coming out of their lab.

We see K1ngs Slayer as a sequel to Orig1n, another Olympus Labs product we reviewed in the past. Both of them were built deliver enhanced muscular gains through naturally-derived ingredients. As our long-time fans know, PricePlow is always skeptical — or at least reasonable with our expectations — when it comes to natural muscle-building products. We’ll compare K1ngs Slayer against its competition in the natural muscle builder arena, not to illegal drugs or exogenous hormones.

K1ngs Slayer Ingredients

Olympus Labs K1ngs Slayer Ingredients

Take a look at K1ngs Slayer’s ingredients and ask yourself how many times you’ve used any of these four: Korean Mistletoe, Hesperidin Methyl Chalcone, Gentiana Lutea, and A. Lancea Rhizome Extract!

K1ngs Slayer contains some novel-ass ingredients we’ve never even seen used before, so this analysis is a learning experience for us. Let’s get to the science!

  • Korean Mistletoe Extract (2g)

    Korean Mistletoe (KME) is a semi-parasitic plant that has been used as a folk “cure-all” for centuries. While supporters believe KME possess anti-tumor, immune-boosting, and anti-diabetic effects,[1-2] recent research has shown that KME can be a powerful tool to combat muscle-wasting.[2,3] In addition, KME may improve endurance and hypertrophy by helping your cellular powerhouses (mitochondria) work more, thereby improving endurance capacity in animals.[15] Further, it may induce processes related to muscle-building, such as the activation of the Akt signaling pathway[2] (a very powerful stimulator of anabolism) and stimulation of GLUT4 synthesis.[1-3]

    Korean Mistletoe reads like a dream when you first see the research. However, we want to see more research before we call it a miracle ingredient.

    Specifically, we want at least one paper showing its benefits in a healthy population. Props to Olympus Labs for using an innovative ingredient, though!

    As always, Olympus Labs isn’t joking around

    You’ll be hard-pressed to find too many supplements with Korean Mistletoe inside (either alone or in a compound supplement like K1ngs Slayer), but from what we’re seeing, 2g is a large dose that likely gets you at or near the human equivalent doses of those studies above.

    Korean Mistletoe Muscle

    This study was done on elderly to prevent muscle-wasting, so keep that in mind, but when it comes to muscle mass, Korean Mistletoe worked![1]

    So right off the bat, we know we’re in “less-conservative” territory, and that’s how it gets once you look for natty muscle builders that venture out of the whole creatine / betaine / protein game Olympus Labs has always been for those who are looking for an extra edge beyond those kinds of ingredients, and it’s no different with K1ngs Slayer. If that’s you, then keep reading, because now it’s time to get hungry.

    Korean Mistletoe Strength

    In addition, Korean Mistletoe yielded some strength gains![1]

    The next two ingredients we have seen a couple times:
  • Hesperidin Methyl Chalcone (750mg)

    Hesperidin is a sugar molecule from citrus fruits such as grapefruit and oranges. It’s a well-proven tool in the fight against bacteria, viruses, and fungi, and it has been shown to inhibit the spread of specific types of cancer in vitro and in mice.[4,5] Honestly, helping you not get sick to allow for more gym time is already a great way to improve your gains. But you know we need more than that.

    So here it goes: Hesperidin may also induce muscle tissue formation (known as myogenic differentiation). It does so by increasing expression of genes in mesenchymal stem cells.[4-7]

    The recovery factor


    Enhanced myogenic differentiation by hesperedin.[6]

    For those that slept during their medical physiology courses, Hesperidin will help you bounce back from muscular damage faster than usual. If you weight train (which is probably any Olympus Labs user who’s reading this), this is something you want. In our opinion, enhancing recovery is one of the best ways for a natural product to help lifters build more size. Fact us, natty’s need to chase volume, and to get more in, we need to chase recovery.

    This is yet another ingredient we would love to see more — Olympus Labs is 2/4 so far on ingredients that have piqued our interest!

  • Gentiana Lutea (600mg)

    To make gains, you need to eat — and some of us just aren’t great at doing it consistently, day in day out. This ingredient — a carryover from Olympus Labs’ Or1gin, may help with that.


    Europeans have been making beverages with the ‘gentians’ for centuries, and selling as a ‘digestive tonic’

    Gentiana Lutea, present as a root extract in K1ngs Slayer, is a herb also known as bitter root that makes most users hungry for more gains. Literally. Gentiana is well known stimulator of ghrelin, a hormone that will drive up your appetite and help you use dietary nutrients more efficiently.[8] It’s long historically been used as a “digestive tonic”, and is is even used as medicine to help patients who have severe eating disorders![16,17]

    While Gentiana won’t change your appetite forever — it’ll help you shovel down more plates of chicken and rice, steak and potatoes… or even Pop Tarts — it’s up to you! If you ask us, most people that struggle with gains suffer from a case of undereating. Just make sure you still track your food!

    Anecdotal Opinion on Gentiana: This stuff’s wild!

    This ingredient has worked on us every time we’ve tried it in the past. For me, it’s not so much as “making me hungry”, but it’s been more about “never getting full”. It’s a wild effect, and for small eaters who want to get bigger, makes K1ngs Slayer worth a shot all on its own.

    Olympus Labs K1ngs Slayer Benefits

    Appetite Stimulator, you say? You can nearly bet on it!!

    There is also synergy at play here. Hesperidin also can help rev up ghrelin secretion. Taking both ingredients together should get your appetite going.[9] Not only that, but Olympus Labs isn’t done yet. They drilled up your hunger even more with the following:

  • Atractylodes Lancea Rhizome Extract (300mg)

    Often extracted for atractylodin, Atractylodes lancea rhizome is a Japanese herb that’s well-known as a modulator of Ghrelin secretion in the body. It works as an agonist of growth hormone secretagogue receptor (GHSR) and ghrelin receptor agonist, while the main constituent atractylodin promotes gastric emptying, further stimulating appetite.[19] We consider this a “metabolism mover” of sorts.

    Recent research, specifically in those that suffer from Cachexia (a condition marked by loss of appetite and lean body mass from hypocaloricism) shows that traditional Japanese medicines containing A. Lancea may improve appetite and lean body mass retention.[10-11]

    Note: You may sometimes see atractylodin come from something known as Rikkunshito — but that’s actually a traditional Japanese medicine that contains Atractylodes lancea rhizome as one of its ingredients. Hesperidin listed above is another common ingredient in Rkkunshito!

    You may also see this herb spelled as Atractylodis lanceae rhizoma in research.[20]

At this point, we’re realizing that K1ngs Slayer is more like a natural Korean Mistletoe powered anabolic that pushes appetite, and this profile backs that up. So let’s talk about the mechanism at hand:

Why is Ghrelin Such a Good Thing?

Ghrelin Pathway

For obese individuals, ghrelin is the last thing we want to ramp up any more. But for hard-gainers and small-eaters, it’s time to rev the engine!

By now, you’ve realized that 75% of K1ngs Slayer’s formula helps your body produce more ghrelin. We thought to explain why this is something you would want. Ghrelin is a hormone in the body that is an agonist of the growth-hormone secretagogue receptor most associated with appetite. While improving appetite in hard-gaining athletes is a big deal on its own, ghrelin can also stimulate growth hormone secret, IGF-1 release, and can even help improve digestion.[10-12]

That IGF-1 release is beneficial since it raises serum alkaline phosphatase, the cellular process for bone formation, and is linked to muscle development. Combined with an increased diet and aggressive training, this should all lead to additional muscle growth potential.

By targeting Ghrelin with much of its formula, but tagging it with a “new” anabolic ingredient, K1ngs Slayer uses a novel approach when compared to other natural muscle building products. Hell, we’d love to see a study on this specific formula in terms of ghrelin release. We’re insanely confident appetite will be ramped up for those who need it.

If you eat in a surplus (consistently following a high-protein plan and sticking to your macro goals) and train aggressively you will gain muscle. This much we know. But if you do all of that and add in Korean Mistletoe and these other ingredients, which should increase nutrient uptake, we’re confident there will be even more improvements to skeletal muscle mass. But you have to eat.

Rikkunshito Mechanism

How Rikkunshito works – K1ngs Slayer has the atractylodin on the left side to boost appetite


K1ngs Slayer is a fine addition to the Olympus Labs canon, and basically what Olympus Labs kind of customers are looking for – novel ingredients that will force you to adapt and respond. It’s also the kind of stuff we’ve been missing writing about on this blog, which is why we’re happy to have Team Olympus back in the fold (still gonna try that Re1gn pre workout..)

Olympus Labs

Welcome back to the show! See all Olympus Labs supplements on PricePlow

Since most of our followers have not encountered these ingredients, K1ng Slayer may be worth trying just for the novelty of the formulation — if you’re more on the ‘aggressive’ scale with solid doses of new ingredients. For those that struggle with eating and gaining mass, we think K1ngs Slayer has a complete edge over its competition. Our only complaint is the massive amount of capsules per serving: six capsules is a lot, but that’s how it goes when your first ingredient has a whopping 2g dose.

Like we said, Olympus Labs doesn’t mess around, and that’s why we’re glad to have em back.

Olympus Labs K1ngs Slayer - Deals and Price Drop Alerts

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No spam, no scams.

Disclosure: PricePlow relies on pricing from stores with which we have a business relationship. We work hard to keep pricing current, but you may find a better offer.

Posts are sponsored in part by the retailers and/or brands listed on this page.

About the Author: Mike Roberto

Mike Roberto

Mike Roberto is a research scientist and water sports athlete who founded PricePlow. He is an n=1 diet experimenter with extensive experience in supplementation and dietary modification, whose personal expertise stems from several experiments done on himself while sharing lab tests.

Mike's goal is to bridge the gap between nutritional research scientists and non-academics who seek to better their health in a system that has catastrophically failed the public.

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  1. Lim, N. J., Shin, J. H., Kim, H. J., Lim, Y., Kim, J. Y., Lee, W. J., . . . Kwon, O. (2017). A combination of Korean mistletoe extract and resistance exercise retarded the decline in muscle mass and strength in the elderly: A randomized controlled trial. Experimental Gerontology, 87, 48-56; https://www.ncbi.nlm.nih.gov/pubmed/27845200
  2. Jeong, J., Park, C., Kim, I., Kim, Y., Yoon, J., Kim, K., & Kim, J. (2017). Korean mistletoe (Viscum album coloratum) extract regulates gene expression related to muscle atrophy and muscle hypertrophy. BMC Complementary and Alternative Medicine, 17(1); https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5251312/
  3. Lee, S., Kim, I., Kim, J., Park, D., & Min, K. (2014). The effects of Korean mistletoe extract on endurance during exercise in mice. Animal Cells and Systems, 18(1), 34-40; https://www.researchgate.net/publication/281852096_The_effects_of_Korean_mistleote_extract_on_endurance_during_excercise_in_mice
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  6. Jeong, H., Lee, J. Y., Jang, E. J., Lee, E. H., Bae, M. A., Hong, J., & Hwang, E. S. (2011). Hesperedin promotes MyoD-induced myogenic differentiation in vitroandin vivo. British Journal of Pharmacology, 163(3), 598-608; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3101621/
  7. Akiyama, S., Katsumata, S., Suzuki, K., Ishimi, Y., Wu, J., & Uehara, M. (2009). Dietary Hesperidin Exerts Hypoglycemic and Hypolipidemic Effects in Streptozotocin-Induced Marginal Type 1 Diabetic Rats. Journal of Clinical Biochemistry and Nutrition, 46(1), 87-92; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2803138/
  8. Janssen, S., Laermans, J., Verhulst, P.-J., Thijs, T., Tack, J., & Depoortere, I. (2011). Bitter taste receptors and α-gustducin regulate the secretion of ghrelin with functional effects on food intake and gastric emptying. Proceedings of the National Academy of Sciences of the United States of America, 108(5), 2094–2099; http://www.pnas.org/content/108/5/2094
  9. Suzuki H et al. Recent Pat Food Nutr Agric. 2014;6(1):60-3; “Hesperidin potentiates ghrelin signaling”; https://www.ncbi.nlm.nih.gov/pubmed/25176345
  10. Hattori, T. (2010). Rikkunshito and Ghrelin. International Journal of Peptides, 2010, 283549; https://www.hindawi.com/journals/ijpep/2010/283549/
  11. Fujitsuka, N., & Uezono, Y. (2014). Rikkunshito, a ghrelin potentiator, ameliorates anorexia–cachexia syndrome. Frontiers in Pharmacology, 5, 271; https://www.frontiersin.org/articles/10.3389/fphar.2014.00271/full
  12. Mogami, S., & Hattori, T. (2014). Beneficial Effects of Rikkunshito, a Japanese Kampo Medicine, on Gastrointestinal Dysfunction and Anorexia in Combination with Western Drug: A Systematic Review. Evidence-Based Complementary and Alternative Medicine : eCAM, 2014, 519035; https://www.hindawi.com/journals/ecam/2014/519035/
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