The Short Version
Every vegan protein powder starts with a plant (or a fungus) and a factory. The source decides how much protein lands in a scoop, which amino acid runs short, and whether it trips an allergy.
Quick verdict: pea is the workhorse. All 12 powders in our top 12 use it. Pea plus rice is the classic blend because each covers the other’s weak spot. Soy is the most complete single source here, but it’s a major allergen. The newer sources have thin data and few tubs.
All 13 Sources on One Table
“Weak amino acid” is the essential amino acid that runs out first. “Major allergen” means one of the nine the FDA requires on US labels.
| Source | Typical protein content | Weak amino acid | Major US allergen? | Texture and taste | In our top 12 |
|---|---|---|---|---|---|
| Pea | About 80% for isolates; Naked Pea’s label works out to 90% | Methionine (+ cysteine) | No | Earthy when unflavored; can be gritty | All 12 |
| Brown rice | About 80% | Lysine | No | Mild; texture varies by brand | 6: ON, Purely Inspired, Garden of Life, Thorne, Momentous, Orgain |
| Pea + rice blend | Depends on the mix | Smaller gaps than either alone | No | Depends on the recipe | The same 6 |
| Soy | 90% or more for isolate (Codex definition) | Methionine + cysteine, a small gap | Yes | Mild, sometimes beany | None |
| Hemp | About 50% | Lysine; leucine is low too | No | Nutty, earthy, less refined | None |
| Pumpkin seed | About 54% in defatted seed meal; isolates higher | Lysine | No | Off-flavors and color are a known hurdle | Vega, Truvani, KOS (plus Garden of Life’s sprouts) |
| Fava bean | Up to 90% (one maker’s isolate) | Methionine + cysteine | No | Maker claims a clean taste | ON |
| Mung bean | Over 80% (FDA GRAS notice) | Methionine + cysteine | No | Few powder reviews yet | Orgain |
| Chickpea | 86–90% in lab-made isolates | Methionine | No | Few powder reviews yet | Garden of Life (sprouted garbanzo) |
| Lupin | 61% in one lab test | Methionine + cysteine; lysine and leucine low too | No in the US, yes in the EU; peanut warning | Few powder reviews yet | None |
| Duckweed (water lentil) | About 85% (one maker’s claim) | Not well established | No | Maker claims a neutral taste | None |
| Yeast | About 82% in one lab sample | Not well established | No | Researchers call it non-beany | None |
| Fermented (a process) | Follows the base; one fermented pea-rice ingredient is 75%+ | Follows the base | Follows the base | Pitched as smoother | None |
Why Protein Scores Disagree
Pea protein scored a DIAAS of 1.00 in a 2022 human study of 15 volunteers fitted with gut-sampling tubes. Casein scored 1.45, so pea didn’t “match” dairy; it cleared the bar. Staff from Roquette, a pea-protein maker, co-authored it. Pooled pig data put pea at 0.70, using the scoring pattern for young children that FAO recommends for regulation (Herreman 2020). Same protein, different method, different yardstick. Use the numbers to compare sources, not to grade your tub.
Each Source, Up Close
Pea
Yellow split pea is the default. Three of our 12 show how much they lean on it: Naked Pea is pea and nothing else, Ritual adds L-methionine (pea’s weak spot) to its pea, and a Momentous batch certificate lists 24.9 g of pea protein to 1.03 g of brown rice protein. In a lab analysis, three commercial pea isolates ran 77–81% protein, with methionine at 0.4% of the protein (Gorissen 2018).
The muscle study everyone quotes: in a 12-week trial, 161 young men took 25 g of pea, whey or placebo twice a day while training. Overall, group differences were only a trend. Among the weakest starters, pea beat placebo for biceps thickness; whey wasn’t different from either. Roquette staff co-authored it too. More: pea vs soy and isolate vs concentrate.
Brown rice
Rice is pea’s mirror image. A commercial brown rice protein tested at 79% protein, with lysine at 2.4% of the protein (below the WHO/FAO/UNU requirement) and methionine at 2.5% (Gorissen 2018). Pooled pig data give rice a DIAAS of 0.47, limited by lysine (Herreman 2020). In an 8-week study of 24 trained men, 48 g of rice protein isolate after training gave changes in body composition and strength no different from 48 g of whey isolate. Small study, big scoop.
Pea + rice blends
Pea is low in methionine; rice is low in lysine. Blend them and the gaps shrink: modeling from the pooled pig data puts the best mix at a DIAAS of about 0.84, with roughly 41% rice (Herreman 2020). Six of our 12 pair the two: ON, Purely Inspired, Garden of Life, Thorne, Momentous and Orgain. Labels list ingredients heaviest first (21 CFR 101.4) but rarely give the ratio. More: is vegan protein complete?
Soy
Soy scored 0.91 in the pooled pig data, the best of the six sources here that the dataset covers (Herreman 2020). The Codex soy standard defines soy protein isolate as at least 90% protein on a dry basis, and concentrate as 65% to under 90%. The catch: soy is one of the nine major food allergens. None of our top 12 uses soy protein, and the three that use lecithin (ON, Ritual, Orgain) use sunflower lecithin. Avoiding soy? Read vegan protein without soy.
Hemp
A commercial hemp protein tested at 51% protein, with leucine at 5.1% of protein, both the lowest of the 10 plant proteins studied. To get 2.7 g of leucine you’d need about 54 g of hemp protein, against 38 g of pea (Gorissen 2018). A Canadian study of 30 hemp seed products found lysine was first-limiting in all of them; dehulled seed scored a PDCAAS of 0.63 to 0.66. None of our top 12 uses hemp.
Pumpkin seed
A 2025 review puts defatted pumpkin seed at about 54% protein, names lysine the first limiting amino acid in pumpkin seed protein isolate, and flags off-flavors and color from the seed’s natural phenolic compounds. In our 12 it plays support in Vega, Truvani and KOS. More in our pumpkin seed protein guide.
Fava bean
Roquette says its fava isolate is 90% protein. Pooled pig data score fava at 0.55, short on methionine and cysteine (Herreman 2020). Fava beans also contain vicine and convicine, the trigger for favism in people with G6PD deficiency (Martineau-Côté 2022); labels don’t say how much survives into an isolate. In our 12: ON, next to pea and rice. See fava bean protein.
Mung bean
Mung bean protein isolate got an FDA “no questions” letter on its GRAS notice in 2017; the maker described it as over 80% protein on a dry basis. The notice itself names methionine and cysteine as limiting and puts PDCAAS at about 0.50 to 0.56 in rat tests. Orgain is the only one of our 12 using it. See mung bean protein.
Chickpea
Lab-made chickpea protein isolates ran 86–90% protein and were deficient in methionine (Onder 2023). In our 12, chickpea shows up only as sprouted garbanzo, one of 12 sprouts in Garden of Life’s blend. See chickpea protein.
Lupin
The FDA says people allergic to peanuts may also react to lupin, sometimes severely, and US labels don’t have to flag it, while European labels do. A commercial lupin protein tested at 61% protein, low in lysine, methionine and leucine (Gorissen 2018); pooled pig data score it 0.68. None of our 12 uses it. See lupin protein.
Duckweed
Duckweed (Lemna and Wolffia, sold as water lentils) is pond life with a protein résumé. In February 2026 the FDA said it had no questions about Plantible’s GRAS notice for Lemna leaf protein, which the company says is about 85% protein. In a small trial, 36 men ate whole Wolffia, peas or soft cheese: several essential amino acids rose in the blood about equally, while leucine, isoleucine and valine rose more after cheese. See duckweed protein.
Yeast
Yeast protein isn’t a plant. It’s a fungus grown in tanks, and still vegan. A 2023 lab comparison found a commercial yeast protein was 82.4% protein, with lab-measured digestibility of about 85%; the authors describe its taste as non-beany. Human data are thin. See yeast protein.
Fermented
Fermented is a process, not a source. Microbes work on a base protein, usually pea, rice or both, and the protein facts follow that base. One example: pea and rice protein fermented with shiitake mycelium, which the UK Food Standards Agency describes as at least 75% protein (FSA). The FSA also said a fermented pea protein would likely be a risk for people allergic to pea (FSA). See fermented vegan protein.
The supporting cast
Some ingredients play small parts in a blend: chia (Truvani, Thorne, Orgain, KOS), sunflower seed (Vega), quinoa (PlantFusion, KOS), amaranth (PlantFusion), flax (KOS) and algae (PlantFusion; chlorella in Garden of Life).
Food allergy (peanut and lupin can cross-react), G6PD deficiency, kidney disease or a baby on the way? Ask your doctor or pharmacist before you add a new protein powder.
Top Picks by Type
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Naked Pea Protein: Single-source pea, our #1 (84/100). 27 g protein per 2-scoop serving, Informed Choice and NSF Contents Certified. No published heavy-metal numbers.
Naked Pea Protein$57.99 as of Nov 11, 1:33 AM ETCheck price on Amazon →Read our review → -
Vega Protein + Recovery: Pea plus seeds, #2 (71/100). Pea, pumpkin seed and sunflower seed protein, 30 g per scoop, NSF Certified for Sport. Consumer Reports hasn’t tested the current formula.
Vega Protein + Recovery$44.99 as of Nov 11, 1:33 AM ETCheck price on Amazon →Read our review → -
Optimum Nutrition Gold Standard 100% Plant Protein: Pea, fava and rice, #4 (69/100). The only one of our 12 with fava bean protein isolate, 24 g protein per scoop, Informed Choice certified.
Optimum Nutrition Gold Standard 100% Plant Protein$34.99 as of Nov 11, 1:33 AM ETCheck price on Amazon →Read our review → -
Garden of Life Raw Organic Protein: Pea plus sprouts, #6 (68/100). Organic pea and sprouted brown rice plus 12 sprouted seeds and legumes, 22 g per scoop. Sweetened with erythritol and stevia.
Garden of Life Raw Organic Protein$35.69 as of Nov 11, 1:33 AM ETCheck price on Amazon →Read our review →
Glossary: Label and Science Terms
- Isolate
- Protein refined to strip out most of the starch, fat and fiber. Soy is the source with a formal cutoff: 90% protein or more on a dry basis, per the Codex standard. For other sources, grams of protein per scoop tell you more than the word.
- Concentrate
- Less refined, so more of the plant comes along. For soy, Codex sets it at 65% to under 90% protein.
- Essential amino acids (EAAs)
- The nine your body can’t make: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
- Complete protein
- A protein with all nine EAAs in the amounts you need. Most plant proteins contain all nine; “incomplete” usually means one runs low, not that it’s missing.
- Limiting amino acid
- The EAA that runs out first. For legumes like pea, soy, fava and lupin it’s usually methionine plus cysteine; for grains and hemp it’s lysine (Herreman 2020).
- Leucine
- The amino acid sports-nutrition research watches most closely for muscle protein synthesis. The ISSN position stand suggests 20–40 g of protein per dose, with 700–3,000 mg of leucine. Naked Pea publishes 2.5 g per serving and Thorne 1.9 g.
- BCAAs
- Branched-chain amino acids: leucine, isoleucine and valine. A BCAA total says little about leucine alone.
- PDCAAS
- Protein Digestibility Corrected Amino Acid Score. The older score, capped at 1.0. US labels use it: the %DV for protein is PDCAAS-corrected and only required when the label makes a protein claim or the food is meant for kids under 4 (21 CFR 101.9).
- DIAAS
- Digestible Indispensable Amino Acid Score. The FAO recommended it in 2013 to replace PDCAAS. It uses the digestibility of each amino acid at the end of the small intestine and isn’t capped. Under 0.75 earns no quality claim, 0.75 to 0.99 is “high,” 1.00 and up is “excellent.”
- Added amino acids
- Free amino acids mixed in, like PlantFusion’s BCAAs and glutamine or Ritual’s L-methionine. US labels can calculate protein from nitrogen, so these count toward the grams.
- Sprouted
- Seeds or grains germinated before processing. It’s a description, not a certification. One lab study cited in a faba bean review found 72 hours of germination didn’t change the PDCAAS.
- Fermented
- Protein treated with microbes such as bacteria, yeast or mushroom mycelium. The protein facts still follow the base.
- Organic, Non-GMO, certified
- Organic and Non-GMO cover farming; testing seals cover what’s in the tub. How to check each: how to choose.