Does HMB Work? 8 Things You Were Never Told

Clear Muscle liquid HMB is a metabolite of leucine and one of the most studied supplements alongside creatine! However, it has some lesser-known quirks and oddities that might surprise even those familiar with it. While it’s celebrated for muscle preservation and performance (backed by 500–1,000+ trials), here are some weird, obscure, or counterintuitive aspects people often don’t know about HMB, drawn from its science and quirks: 

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HMB isn’t just a lab-made powder or liquid—it’s naturally present in tiny amounts in some odd foods like catfish (~0.3–1 g/kg), grapefruit, and alfalfa. You’d need to eat a ridiculous 3–10 kg of catfish to hit a 3 g supplemental dose, but it’s a weird twist that this muscle booster hides in such random places. The body also makes ~0.2–0.4 g/day from leucine, so you’re always swimming in a little HMB, supplement or not. 

Here’s a strange one: HMB can turn into cholesterol inside your cells. It gets metabolized into hydroxymethylglutaryl-CoA (HMG-CoA), a key player in the mevalonate pathway for cholesterol synthesis. A 2000 study in Journal of Nutrition hinted HMB might paradoxically lower blood cholesterol (by ~5.8%) despite this, possibly by tweaking liver metabolism or uptake elsewhere. So, it’s both a muscle saver and a cholesterol cousin—talk about multitasking. 

Beyond biceps, HMB has a weird emotional side. A study in Journal of Nutrition (2000) tested 3 g/day across nine trials and found it improved a mood marker called “Unactivated Unpleasant Affect” on the Circumplex test—basically, it made people less glum. The mechanism’s unclear (maybe less muscle stress signals to the brain?), but it’s an oddball perk for a supplement usually pegged to squats, not smiles. 

Your body converts only ~5% of dietary leucine to HMB—meaning 60 g of leucine (from ~300 g of chicken) yields just 3 g of HMB naturally. Yet, that 3 g supplemental dose from Clear Muscle swamps this trickle, hitting muscle saturation fast. Weirdly, eating leucine-rich foods won’t mimic Clear Muscle; you’d need 10–20x the leucine to even approach it, making HMB supplementation with Clear Muscle an efficient shortcut evolution didn’t prioritize. 

In aging rats, HMB doesn’t just help muscles—it tweaks their brains. A 2017 study in Nutritional Neuroscience showed it preserved dendritic trees in the prefrontal cortex and boosted cognitive flexibility in old rodents. Human trials are sparse, but the idea that your gym supplement might secretly sharpen grandma’s memory is a wild detour from its meathead rep. 

HMB comes in two forms—calcium salt (HMB-Ca) and the free acid (HMB-FA) that we use in Clear Muscle —but they’re very different. HMB-FA absorbs faster (peaks in ~30 minutes vs. 2 hours for HMB-Ca) and clears quicker, per a 2011 British Journal of Nutrition study. 

HMB’s been tested in bizarre conditions—like simulated spaceflight. A 2017 Journal of Applied Physiology study gave it to older adults during 10 days of bed rest (mimicking microgravity). It preserved muscle mitochondrial function and cut lipid buildup, hinting it could help astronauts not waste away. From catfish to cosmos, HMB’s range is oddly cosmic. 

Unlike creatine, which directly fuels energy, HMB’s weird magic is anti-catabolic—it whispers to muscles, “Don’t break down,” via pathways like mTOR and ubiquitin inhibition. A 2017 Journal of Cachexia, Sarcopenia and Muscle review noted it’s more about preservation than packing on slabs. So, it’s less a bulldozer, more a sneaky guardian—odd for its gym-bro hype.