The best fiber supplement in 2025 based on expert reviews and quality standards is Thorne FiberMend. It is praised for its effective ingredients and high-quality manufacturing. Key features include:

• Form: Powder
• Fiber content: 7 g of dietary fiber per serving (25% DV), using Sunfiber AG, a water-soluble fiber derived from guar beans
• Benefits: Supports regular bowel movements, treats occasional diarrhea and constipation, promotes digestive health
• Additional ingredients: Contains green tea phytosome (caffeine-free green tea extract) which may improve blood pressure and blood lipid levels, and has antioxidant properties
• Free from gluten, dairy, soy, artificial flavors, and colors
• Unflavored and mixes well with any food or liquid
• Higher price point, but offers clinical research-backed benefits

Other notable options include:

• Bellway Super Fiber + Fruit: psyllium husk-based, gentle on the stomach
• Renew Life Superfood Organic Prebiotic Fiber: keto-friendly with tapioca dextrin and whole fruits/vegetables
• Pure Encapsulations PureLean Fiber: supports weight loss with a blend of soluble and insoluble fibers
• Fiber Choice Prebiotic Fiber Gummies: convenient gummy form with inulin fiber

For overall best effectiveness, quality, and versatility, Thorne FiberMend is the top choice for 2025.