This is an open-label, two-arm pilot study designed to evaluate the tolerability, consumer acceptability, and well-being outcomes of a multi-ingredient protein formula, available in two flavors (Vanilla Protein Formula and Chocolate Protein Formula), in generally healthy adults aged 21-65 with a BMI of 18.5-34.9 kg/m². Approximately 50 participants will be allocated in a 1:1 ratio, balanced on age and gender, to receive either the vanilla or chocolate formula (approximately 25 participants per arm). Participants will consume one serving (1 scoop, 51 grams) of their assigned product daily for 15 consecutive days, reconstituted in water or a beverage of their choice. The primary outcomes are safety and tolerability, assessed via a Safety and Tolerability Questionnaire, and changes in global health assessed using the Global-10 scale. Secondary outcomes include changes in cognitive function assessed using the PROMIS v2.0 Cognitive Function - Abilities 8a instruments, and consumer acceptability, measured using a 9-point hedonic liking scale. All assessments are self-reported and completed electronically at home.
Adults aged 21-65 years, inclusive
Generally healthy, as determined by self-reported medical history and investigator judgment
Body mass index 18.5-34.9 kg/m² (as operationally verified)
Willing and able to consume the test product once daily for 15 days and to complete scheduled questionnaires
Known allergy or intolerance to any study-product component, including yeast-derived protein, bovine collagen, creatine, the prebiotic fiber blend, allulose, or Reb M.
Women who are pregnant, breastfeeding, or planning to become pregnant or start breastfeeding during the trial
Clinically significant gastrointestinal disorder that could confound tolerability assessment (e.g., inflammatory bowel disease, symptomatic irritable bowel syndrome, prior major GI surgery), per investigator judgment
Known renal impairment or condition for which supplemental creatine is not advised
Parallel
Vanilla Protein Formula
Dietary supplementA vanilla-flavored, multi-ingredient ready-to-mix powdered dietary supplement combining YESTEIN fermented yeast protein, grass-fed bovine collagen peptides, OptiCreatine creatine monohydrate, and FiberEssence prebiotic fiber blend, sweetened with allulose, Reb M, and coconut sugar. Each 51-gram serving (1 scoop) provides 24 g protein, 2 g sugar, 3.5 g fat, and 5 g fiber. Consumed once daily for 15 days.
Chocolate Protein Formula
Dietary supplementA chocolate-flavored, multi-ingredient ready-to-mix powdered dietary supplement combining YESTEIN fermented yeast protein, grass-fed bovine collagen peptides, OptiCreatine creatine monohydrate, and FiberEssence organic prebiotic fiber blend, flavored with cocoa powder and organic natural cocoa extract, sweetened with allulose, Reb M, and coconut sugar, and containing MCT oil powder. Each 51-gram serving (1 scoop) provides 25 g protein, 2 g sugar, 3.5 g fat, and 5 g fiber. Consumed once daily for 15 days.
Change from baseline in Safety and Tolerability Questionnaire symptom scores at Day 15
Safety and tolerability of daily use of the protein formula. Each symptom item (increased anxiety/worry, headache, mood changes, stomach upset/nausea, dizziness, bloating, itching, sexual dysfunction) is rated 1 (not at all) to 5 (a great deal); higher score = worsening of symptoms.
Change from baseline in PROMIS Global Health (Global-10) T-scores at Day 15
PROMIS Global Health v1.2 (10 items) yields Global Physical Health (GPH) and Global Mental Health (GMH) T-scores (mean 50, SD 10 in the reference population); higher T-scores = better health. Pooled across both flavor arms.
Overall product liking on the 9-point hedonic scale at Day 15, by flavor arm
Overall liking rated 1 (dislike extremely) to 9 (like extremely); flavor and texture/mouthfeel/aftertaste are rated on the same scale. Summarized separately for the vanilla and chocolate arms.
Change from baseline in PROMIS v2.0 Cognitive Function - Abilities Short Form 8a T-score at Day 15
Eight items each scored 1-5 (raw score 8-40), converted to a T-score (mean 50, SD 10); higher = better perceived cognitive function. Pooled across both flavor arms.
Change from baseline in Safety and Tolerability Questionnaire symptom scores at Day 7
Mid-study safety and tolerability. Each symptom item (increased anxiety/worry, headache, mood changes, stomach upset/nausea, dizziness, bloating, itching, sexual dysfunction) is rated 1 (not at all) to 5 (a great deal); higher score = worsening of symptoms.
Just-About-Right (JAR) sweetness rating at Day 15, by flavor arm
Sweetness rated 1 (far too little) to 5 (far too much), with 3 = just about right. Summarized separately by flavor arm.
Adherence and study completion
Proportion of scheduled servings consumed, from check-in surveys on Days 1, 3, 7, and 15, and the proportion of participants completing the Day 15 assessment.
End-of-study Follow-Up Questionnaire: overall product experience, product rating, and purchase interest
Self-reported overall experience with the product, product rating, and purchase intent (5-point scale from 'definitely would not buy' to 'definitely would buy').
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