Training studies used 25–40 g/day soy isolate for 8–12 weeks with exercise
Reviewed · Published
Soy protein
A plant protein providing all essential amino acids.
Established functions
- A plant protein providing all essential amino acids.
Dietary sources
- soybeans
- tofu
- soy milk
Claims and evidence
Claims that Soy protein alone prevents or treats disease, or invariably improves health without deficiency, are unsupported.
Japanese reference amounts
- Japanese adults (age and sex as specified): Protein goal for adults: 1.0 g/kg body weight/day
Amounts studied
- Training studies used 25–40 g/day soy isolate for 8–12 weeks with exercise
Tolerable upper limits
- No protein-specific UL; concentrated isoflavones require separate assessment
Forms and bioavailability
Supplement forms: soy isolate, soy concentrate
- Heating reduces trypsin inhibitors; isolate has higher protein density.
Safety and interactions
Adverse effects
- bloating
- soy allergy
Medicine and nutrient interactions
- levothyroxine, iron; separate timing
Contraindications and cautions
- Do not use with soy allergy.
Practical selection
- Compare Soy protein amount per serving, form, allergens, and batch testing; prefer a single-ingredient product suited to the intended use.
Sources and review
- Protein intake and exercise position standInternational Society of Sports Nutrition
Daiki Minaki (editorial and evidence review) ·
Frequently asked questions
How is Soy protein different from its broader supplement category?
A plant protein providing all essential amino acids. Compare its named form and amount rather than assuming every category product supplies it.
View detailsWhat safety detail matters specifically for Soy protein?
levothyroxine, iron; separate timing Do not use with soy allergy.
View details