Who Makes the Best Whey? A Guide to Top Brands in 2025

January 9, 2026 •

4 min read

According to a 2025 review and meta-analysis, whey protein may help improve cholesterol levels, among other health benefits. But with dozens of brands flooding the market, figuring out who makes the best whey can be a daunting task for consumers. This comprehensive guide breaks down the essential factors to consider when choosing a protein powder and highlights the top contenders of 2025.

Quick Summary

Choosing the best whey depends on your goals, dietary needs, and budget. This guide breaks down whey types and compares top-rated brands based on purity, taste, and third-party testing to help you find the right fit.

Key Points

Top Contenders: Optimum Nutrition Gold Standard, Transparent Labs Grass-Fed Isolate, and Dymatize ISO 100 are consistently top-rated whey protein brands in 2025.
Isolate vs. Concentrate: Whey Isolate is more refined, higher in protein, and lower in fat and lactose, making it ideal for low-carb diets and sensitive digestion. Concentrate is more affordable and retains more natural nutrients.
Third-Party Testing Matters: Look for certifications like Informed Choice or NSF to verify a product is free from contaminants and banned substances. This is crucial for safety and label accuracy.
Prioritize Your Goals: Choose based on your objective. Isolate is often preferred for weight loss and quick recovery, while a concentrate can be suitable for bulking or general fitness.
Consider Digestion: Individuals with lactose intolerance or sensitive stomachs should opt for a whey isolate or hydrolysate to minimize bloating and discomfort.

The Three Main Types of Whey

Whey protein is derived as a byproduct during the cheese-making process from milk. While many see it as a single supplement, whey comes in three primary forms, each with a distinct nutritional profile and rate of digestion. Understanding these differences is crucial for selecting the right powder for your needs.

Whey Protein Concentrate (WPC)

This is the most common and budget-friendly type of whey protein. WPC is less processed, typically containing 70–80% protein by weight. The remaining portion includes carbohydrates, fats, and lactose. Because it is less filtered, it retains more of the natural nutrients and beneficial compounds found in milk, such as immunoglobulins. WPC is an excellent, affordable option for beginners and individuals without lactose sensitivity who are looking to increase their daily protein intake.

Whey Protein Isolate (WPI)

WPI undergoes more extensive processing to remove a significant portion of the fat, carbs, and most of the lactose, resulting in a product that is at least 90% protein by weight. This higher purity means it is absorbed and digested very quickly. WPI is an ideal choice for those with lactose intolerance or individuals on a strict low-carb or low-fat diet, such as those aiming for weight loss. Brands like Transparent Labs are known for their high-quality grass-fed whey isolates.

Whey Protein Hydrolysate (WPH)

This is the most refined and most expensive form of whey protein. WPH is considered "pre-digested" because it has been exposed to heat or enzymes that break down the protein into smaller peptides. This allows for the fastest possible absorption by the body. Because of this, WPH is often used in medical protein supplements, infant formulas, and by athletes looking for ultra-rapid recovery. Dymatize's ISO 100 is a prominent example of a hydrolyzed whey protein.

How to Choose the Best Whey: Key Considerations

Navigating the supplement aisle requires a discerning eye. Here are the most important factors to evaluate when shopping for your next tub of whey.

**1. Third-Party Testing and Purity

Independent testing is arguably the most important factor for ensuring a product's safety and effectiveness. Reputable organizations like Informed Choice, NSF Certified for Sport, and ConsumerLab.com test for banned substances and contaminants like heavy metals. A 2025 Consumer Reports investigation found that some protein powders contained concerning levels of heavy metals, highlighting why a certification matters.**

**2. Ingredients and Additives

Some brands use artificial sweeteners (like sucralose) and flavors to enhance taste, while others stick to natural ingredients. For individuals with sensitive stomachs, artificial sweeteners can sometimes cause digestive distress. Check the label for unnecessary fillers, and if you prefer a cleaner profile, look for brands that use natural sweeteners like stevia.**

**3. Taste and Mixability

While taste is subjective, some brands consistently earn high marks for flavor and mixability. A protein powder that tastes great and dissolves easily, without clumps, is more likely to be consumed consistently. Customer reviews and independent taste tests are reliable sources for this information. Brands like Optimum Nutrition are known for their wide variety of consistently good flavors.**

**4. Your Goals and Macro Profile

Are you looking to build lean muscle, lose weight, or simply supplement your protein intake? Your goals should dictate your choice of whey.

For weight loss or lean muscle: A low-fat, low-carb isolate (WPI) is often preferred.
For muscle growth and bulking: A concentrate (WPC) with slightly higher calories might be more suitable.
For sensitive digestion: A hydrolyzed isolate (WPH) is the fastest-digesting and least likely to cause issues.**

Top Whey Protein Brands of 2025: A Comparative Look

Optimum Nutrition Gold Standard 100% Whey

Why it's a top pick: This is arguably the world's most popular whey protein powder, known for its balanced blend of whey isolate, concentrate, and hydrolyzed whey. It delivers 24 grams of protein per serving, mixes exceptionally well, and comes in an extensive array of flavors. It's a reliable, budget-friendly option that's also Informed Choice certified.

Transparent Labs 100% Grass-Fed Whey Isolate

Why it's a top pick: Valued for its clean, all-natural ingredients, this isolate is sourced from 100% grass-fed American cows. With 28 grams of protein per scoop, it contains no artificial sweeteners, colors, or fillers, making it a favorite for those prioritizing purity. It is also third-party tested and highly rated for its taste. The premium quality comes at a higher price point.

Dymatize ISO 100 Hydrolyzed Whey

Why it's a top pick: As a hydrolyzed isolate, ISO 100 is ultra-fast absorbing and gentle on the stomach, which can help prevent bloating and discomfort. It delivers 25 grams of protein with minimal carbs and fat. Despite being a premium hydrolyzed product, it offers good value and is Informed Choice certified, ensuring it's free of banned substances.

Whey Protein Comparison Table


Feature	Optimum Nutrition Gold Standard	Transparent Labs Isolate	Dymatize ISO 100
Type	Blend (Isolate, Concentrate, Hydrolysate)	100% Grass-Fed Isolate	100% Hydrolyzed Isolate
Protein/Serving	24g	28g	25g
Third-Party Tested	Yes (Informed Choice)	Yes (Informed Choice, Informed Protein)	Yes (Informed Choice)
Noteworthy Features	Wide flavor variety, affordable, reliable	Clean ingredients, grass-fed, no artificial additives	Ultra-fast absorbing, excellent for sensitive stomachs
Best For	Beginners, budget-conscious users, general fitness	Purity-focused users, lactose-sensitive individuals	Rapid recovery, sensitive digestion

Conclusion

Ultimately, there is no single best whey for everyone. The ideal choice depends on your specific needs, budget, and dietary preferences. For those new to supplements or on a budget, Optimum Nutrition's Gold Standard provides a reliable, widely available, and great-tasting option. Purity-focused consumers may prefer Transparent Labs' clean, grass-fed formula, while those with digestive sensitivities should consider Dymatize ISO 100 for its rapid absorption and gentle profile. Regardless of your choice, prioritizing brands that offer third-party testing is a crucial step toward ensuring product safety and quality.

To learn more about the importance of third-party testing in supplements, review reports from organizations like the Clean Label Project. Clean Label Project

Frequently Asked Questions

Both whey concentrate and isolate are highly effective for muscle growth. However, isolate is purer and more rapidly absorbed, making it slightly more advantageous for post-workout recovery. For muscle gain, the most important factor is your total daily protein intake.

Whey protein isolate or hydrolysate is generally best for sensitive stomachs. These forms are more refined, removing most of the lactose, which is often the cause of digestive issues like bloating and gas in lactose-intolerant individuals.

Third-party testing by organizations like Informed Choice ensures that the supplement contains what the label claims and is free of harmful contaminants and banned substances. This is especially important given recent reports of heavy metal contamination in some products.

Yes, whey protein quality varies significantly between brands. Differences can include the source of the milk (e.g., grass-fed vs. conventional), processing methods, and the presence of fillers or artificial additives. Higher-quality whey often costs more but offers greater purity.

Optimum Nutrition Gold Standard is an excellent option for beginners due to its balanced blend of whey types, wide range of flavors, and reasonable price point. Its mixability and effectiveness have made it a favorite for years.

The key difference is the ingredient profile. Transparent Labs focuses on a cleaner, grass-fed whey isolate with natural flavors and no artificial additives. Optimum Nutrition is a blend that often includes artificial sweeteners and flavors, though it is more affordable.

For best results, consume whey protein post-workout to maximize muscle recovery, but it can also be used as a snack or to supplement meals throughout the day. It mixes easily with water, milk, or can be added to smoothies and oatmeal.