Soy Protein Isolate: Plant-Based Muscle Fuel & Its Role in Maxine’s Burn
1. What Is Soy Protein Isolate?
Soy Protein Isolate (SPI) is a highly refined, plant-based protein powder containing ≥90% protein by weight. It’s produced by extracting and concentrating the protein fraction of dehulled, defatted soybeans. SPI delivers a complete amino-acid profile—including all nine essential amino acids—making it a viable alternative to dairy proteins for muscle support.
2. Clinically Demonstrated Benefits
2.1 Supports Muscle Protein Synthesis
In a randomized trial comparing 40 g SPI vs. 40 g whey isolate post-exercise, both groups showed equivalent increases in muscle protein synthesis over 3 hours, confirming SPI’s anabolic potential.
2.2 Cardiovascular & Bone Health
Regular intake of 25 g SPI daily for 12 weeks reduced LDL cholesterol by 5–10% and improved arterial stiffness in adults with mild hypercholesterolemia.
2.3 Rich in Bioactive Isoflavones
SPI retains soy isoflavones (genistein, daidzein) that exhibit antioxidant and anti-inflammatory effects, supporting recovery and general wellness.
3. Optimal Dosage & Timing
3.1 Serving
25–40 g per dose, depending on protein goals.
3.2 Frequency
1–2 times daily, ideally:
- Post-Workout: Within 30 minutes to leverage the anabolic window.
- Between Meals: To meet daily protein targets without dairy.
4. Safety & Side Effects
SPI is well tolerated in most adults. Isoflavone content may cause mild gastrointestinal discomfort in sensitive individuals, but no adverse endocrine effects have been demonstrated at typical intakes.
5. Where to Find Soy Protein Isolate in Maxine’s Burn
You’ll find SPI in our snack-style protein offerings:
- Burn Bars: Contain fat burners to ignite your metabolism.
- Burn Cookies: Low in carbohydrates and with only 160 calories per serve.
