NutraBio | Peak O2 | 60 Servings

NutraBio Peak O2 is not trying to be a flashy all-in-one pre-workout. It is a focused, stimulant-free endurance and performance support product built around one branded ingredient: 2 grams of PeakO2™ per scoop. That matters, because PeakO2 is not generic mushroom powder. It is a clinically studied adaptogenic blend from Compound Solutions made from six mushrooms—Cordyceps, Shiitake, Reishi, Turkey Tail, King Trumpet, and Lion’s Mane—formulated specifically for performance, oxygen utilization, fatigue management, and training output.

Mechanistically, PeakO2 works differently than the usual gym ingredients. Instead of chasing a pump or a stimulant spike, it is designed to improve how efficiently your body uses oxygen, support ATP production, and reduce blood lactate accumulation during hard effort. In practice, that means better repeat output, a slower rise in that suffocating burn that cuts sets short, and stronger performance in sessions where endurance, pace, or sustained power matter. The ingredient is also rich in beta-glucans and polysaccharides, compounds associated with adaptogenic stress support and prebiotic activity, giving it a broader physiological footprint than typical ergogenic ingredients.

Dose matters here. PeakO2’s clinical range is 2,000mg to 4,000mg daily, and NutraBio gives you 2,000mg per serving—the entry point of the researched range, not a token inclusion. That is important. Many formulas hide trendy mushroom ingredients in proprietary blends at doses too small to match the literature. Here, the full serving is actually meaningful. The strongest published performance data on PeakO2 has often used 4g daily over roughly 21 days, including university-level research showing improvements in peak power output, VO2 max, lower blood lactate, and longer time to exhaustion. So the honest read is this: 2g is a legitimate evidence-based daily dose, while 4g is closer to the most aggressive protocol used in some standout studies.

As a system, this product is intentionally simple. There are no added stimulants, no amino acids, no pump ingredients, and no overlap to complicate stacking. That makes Peak O2 especially useful alongside creatine monohydrate, beta-alanine, intra-workout carbs, or a stim-based pre-workout when your goal is to build a more complete performance stack. PeakO2’s oxygen-use and fatigue-management profile complements those categories extremely well.

On transparency, this is a mixed but fair picture. NutraBio clearly discloses the active as PeakO2 at 2g, which is far better than the category norm of vague mushroom blends with no meaningful context. However, PeakO2 itself is a branded blend of six mushrooms rather than individually disclosed mushroom amounts. That is standard for the trademarked ingredient, but it does mean you are buying the clinical research behind the branded complex rather than individual gram amounts of each mushroom.

What should you expect? Day 1 is subtle. This is not a tingling, heart-racing product. Most users notice smoother breathing under effort, more stable endurance, and less fade late in sessions rather than an immediate sensation. Over 2 to 4 weeks of consistent daily use, PeakO2 is where the formula becomes more impressive: better tolerance to volume, improved repeat effort, and a more durable engine across lifting, conditioning, and hybrid training. This is performance support for athletes who care about output, not theatrics.

How to Use Nutra Bio | Peak O2