Several protein powders work as effective substitutes for whey, depending on why you’re switching. Soy protein isolate comes closest in overall protein quality, scoring nearly identical to whey on standardized amino acid scales. But pea, rice, egg white, and hemp proteins each have strengths worth considering, and blending two plant proteins together can close the gap with whey almost entirely.
How Protein Quality Is Measured
Protein quality comes down to two things: how complete the amino acid profile is and how well your body absorbs it. Scientists use a scoring system called PDCAAS (Protein Digestibility-Corrected Amino Acid Score) that rates proteins on a scale from 0 to 1.0, with 1.0 being the best. Whey scores a perfect 1.0 on most versions of this scale. How close a substitute gets to that number tells you how efficiently your body can use it for muscle repair and other functions.
Every protein source has a “limiting amino acid,” the essential amino acid present in the lowest amount relative to what your body needs. For plant proteins, that limiting amino acid varies by source, which is why combining two plant proteins often produces a more complete profile than either one alone.
Soy Protein Isolate
Soy is the closest plant-based match to whey. It scores between 0.93 and 1.00 on PDCAAS depending on the evaluation method, compared to whey’s 0.97 to 1.00. On the newer DIAAS scale, soy actually edges out whey slightly (0.92 vs. 0.90). Its limiting amino acid is methionine, but the deficit is small enough that it rarely matters in practice if you’re eating a varied diet alongside your shake.
Soy protein contains all nine essential amino acids in meaningful amounts, making it a complete protein on its own. It has less leucine than whey (leucine is the amino acid most directly responsible for triggering muscle protein synthesis), so if maximizing muscle growth is your primary goal, you may need a slightly larger serving of soy to match whey’s effect. A 30 to 35 gram serving of soy roughly compensates for the leucine difference.
Pea Protein Isolate
Pea protein has become one of the most popular whey alternatives, and for good reason. It’s dairy-free, soy-free, and generally easy on the stomach. Its PDCAAS ranges from 0.78 to 0.91, which is lower than whey but still solidly in the “good quality” range. The limiting amino acid is tryptophan, and it’s also somewhat low in methionine.
Where pea protein really shines is in its lysine content, which is high for a plant source. This makes it an excellent partner for rice protein, which is low in lysine but rich in methionine. On its own, pea protein is a perfectly reasonable substitute if you’re using it as part of a diet that includes other protein sources throughout the day.
The Rice and Pea Blend
Blending pea and rice protein in a roughly 2:1 ratio (two parts pea to one part rice) creates a combined amino acid profile that covers all essential amino acids in sufficient quantities. Pea fills in the lysine that rice lacks, while rice supplies the methionine and threonine that pea is short on. Many commercial “plant protein” powders already use this combination, sometimes with additional sources mixed in.
Rice protein on its own scores poorly, with a PDCAAS of just 0.53 to 0.64 due to its low lysine content. You wouldn’t want to rely on it as a sole protein source. But paired with pea protein, the blend meets the amino acid requirements recommended by the United Nations for a complete dietary protein. If you’re buying individual powders to mix yourself, aim for about two scoops of pea to one scoop of rice.
Egg White Protein
For people avoiding dairy but not animal products, egg white protein is arguably the best whey substitute available. It contains about 83 grams of protein per 100 grams of powder, and it scores a perfect 100 in the amino acid rating system. Your body uses it with remarkable efficiency: studies in rats show a net protein utilization rate of about 94.6%, meaning almost all of the protein you consume gets put to work.
Egg white protein contains all essential amino acids, including generous amounts of leucine and the other branched-chain amino acids important for muscle recovery. It dissolves reasonably well in liquid, though the texture can be slightly thinner than whey. Some people find the taste more neutral, which makes it versatile for smoothies and baking. The main drawback is price, as egg white protein tends to cost more per serving than whey or plant-based options.
Hemp Protein
Hemp protein occupies a unique niche. It’s not the strongest choice for pure protein content, but it brings nutrients that other protein powders don’t. A single serving (about four tablespoons) delivers around 11 grams of fiber, roughly a third of the daily recommended intake for adults. It also contains omega-3 and omega-6 fatty acids that support heart health, immune function, and digestion.
The tradeoff is that hemp has a lower protein concentration per scoop and a less complete amino acid profile than whey, soy, or egg white. It works best as a supplement to an already protein-rich diet rather than a primary muscle-building powder. If you’re someone who struggles to get enough fiber or healthy fats, hemp protein does double duty in a way no other protein powder can. The earthy, slightly nutty flavor pairs well with smoothies that include banana, peanut butter, or cocoa.
Why Collagen Protein Falls Short
Collagen supplements are marketed alongside protein powders, but they’re a poor substitute for whey when it comes to muscle maintenance or growth. Collagen is low in branched-chain amino acids, lysine, and tryptophan, all of which are critical for muscle protein synthesis. In a study comparing 25 grams of whey protein to 26 grams of hydrolyzed collagen, the whey delivered 5.5 grams of branched-chain amino acids while collagen provided just 1.8 grams. Leucine content showed an even starker gap: 2.6 grams from whey versus just 0.1 grams from collagen.
Collagen has legitimate uses for skin, joint, and connective tissue support. But if your goal is replacing whey’s muscle-building and recovery benefits, collagen won’t get you there. Think of it as a complementary supplement, not a swap.
If Lactose Is Your Only Issue
Some people searching for a whey substitute don’t actually need to leave whey behind. If lactose sensitivity is your reason for switching, whey protein isolate contains up to 1 gram of lactose per serving, compared to up to 3.5 grams in whey concentrate. That small amount is tolerable for many people with mild lactose intolerance. Trying an isolate before switching protein sources entirely could save you money and preserve the amino acid profile you’re used to.
Choosing Based on Your Goal
- Maximum muscle building: Egg white protein or soy protein isolate. Both deliver complete amino acid profiles closest to whey.
- Fully plant-based diet: A pea and rice blend in a 2:1 ratio, or soy protein isolate if you tolerate soy well.
- Digestive comfort: Pea protein tends to be gentle on sensitive stomachs and is free of the most common allergens (dairy, soy, eggs, gluten).
- Overall nutrition beyond protein: Hemp protein, for its fiber, omega-3s, and omega-6s.
- Mild lactose intolerance: Whey protein isolate, which removes most of the lactose during processing.
No single substitute matches whey in every category simultaneously, but each option above covers the gap in at least one meaningful way. For most people, soy isolate or a pea-rice blend will be the most practical, affordable, and effective switch.