Buy Twinlab Stress B-Complex - 100 Caps. Stress B-Complex Caps - High Potency...Yeast Free. As with most Twinlab products, Stress B-Complex Caps are well tolerated by most highly allergic individuals. They contain no tablet binders, coatings or colorings. They are also free of the most common allergens such as corn, soy, yeast, barley, wheat, lactose (milk sugar) and all milk, citrus, fish and egg products.