For anyone on a vegan diet, the first difference in pea protein vs whey protein has nothing to do with grams. The NHS describes a vegan diet as one based on plants and foods made from plants. It says vegans do not eat foods that come from animals, including dairy products and eggs.1 Whey comes from milk, so it is a dairy product, while pea protein comes from a plant.2
What pea protein and whey protein are made from
Peas are one of the plant sources ICMR-NIN's Dietary Guidelines for Indians, 2024, list for protein powders, along with soybeans and rice.2 The whole food gives an idea of where pea protein starts. USDA lists boiled split peas at 8.34 g of protein and 8.3 g of fibre in 100 g.3 A pea protein powder concentrates that protein, and its label gives the grams per scoop.
Eaten as a food, peas bring protein and fibre together. A 150 g bowl of boiled split peas gives about 12.5 g of protein, along with almost exactly the same amount of fibre. Split peas are also the base of matar dal, so the protein in a pea powder starts from a familiar Indian food.
Whey starts as the watery part of milk left behind when the curd is taken out for cheese or paneer. It is filtered and dried to raise its protein share, and as with pea protein, the grams in a scoop depend on the product.
A vegan protein comparison of amino acids
The bigger nutritional difference lies in the amino acids. One review of protein sources puts it simply: proteins from plants generally lack one or two of the essential amino acids.4 Whey, as a milk protein, has all nine, and ICMR-NIN counts milk among the animal proteins that carry the full set.2
On a vegan diet, ICMR-NIN's answer is to eat cereals and pulses together, roughly three parts cereal to one part pulse by raw weight. It describes this as the most efficient route to the full set.2 The same guidelines put numbers on a balanced vegan diet. For a moderately active man, it provides more than 80 g of crude protein a day. That works out to about 60 g of quality protein, covering all the essential amino acids.2
Pea vs whey protein for training
Research on pea protein and training is thinner than for whey. The International Society of Sports Nutrition says, in its protein position stand, that interest in pea, rice and hemp protein is growing. It adds that research on how they affect training results is limited so far.5 So if you are looking at plant protein for muscle, the research base is smaller, and your other food has to supply the full set of essential amino acids.
For the day's total, the counting works the same way. If a scoop of pea protein and a scoop of whey each list 20 g of protein, both put 20 g toward the day. The difference lies in what else the scoop carries and whether it fits the way you eat.
Other nutrients to plan on a vegan diet
Protein is only one part of the plan. The NHS lists calcium, iron, vitamin B12, iodine and selenium as nutrients vegans can miss without good planning, and suggests fortified foods or supplements for some of them.1 Fortified soya drinks, pulses, tofu and leafy greens are among the foods it names for calcium and iron.1 Vitamin B12 gets special mention, since sources for vegans are limited and the NHS says a supplement may be needed.1
What the Horlicks Protein sachets list as protein
Horlicks Protein Unflavoured lists whey protein concentrate, which comes from milk, alongside fermented yeast protein, and in the Chocolate and Coffee sachets fermented yeast protein is the only protein named. Each sachet is 36 g with 24 g of protein, made up with 200 ml of cold water or milk.
For a vegan diet, the full ingredients list on any pack, and the liquid it goes into, matter as much as the protein named on the front. The ready-to-drink Horlicks Protein milkshake is made with ultra-filtered milk protein, 20 g a bottle, so it is a dairy drink.
To summarise, pea protein comes from a plant and whey comes from milk, so only pea protein fits a vegan diet as the NHS defines it. Whey carries all nine essential amino acids, and vegans cover the one or two that plant proteins lack by combining cereals and pulses. Research on pea protein and training is still limited compared with whey. Calcium, iron, vitamin B12, iodine and selenium need planning too. On any Horlicks Protein pack, read the full ingredients list, since Unflavoured includes whey protein concentrate and the milkshake is made with milk protein.
Sources
1. NHS. The vegan diet. https://www.nhs.uk/live-well/eat-well/how-to-eat-a-balanced-diet/the-vegan-diet/
2. ICMR-National Institute of Nutrition. Dietary Guidelines for Indians, 2024. https://nin.res.in/dietaryguidelines/pdfjs/locale/DGI_2024.pdf
3. USDA FoodData Central. Peas, split, mature seeds, cooked, boiled, without salt. FDC 172429. https://fdc.nal.usda.gov/food-search/?query=172429&type=SR%20Legacy
4. Hoffman JR, Falvo MJ. Protein, which is best? Journal of Sports Science and Medicine, 2004. PubMed 24482589. https://pmc.ncbi.nlm.nih.gov/articles/PMC3905294/
5. Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise, 2017. PubMed 28642676. https://pmc.ncbi.nlm.nih.gov/articles/PMC5477153/