What is protein and why is it important?

Protein is a macronutrient made of amino acids. It supports muscle repair, immune function, and the production of enzymes and hormones.

How much protein do I need per day?

A common baseline recommendation is about 0.8 g/kg body weight per day, while higher intakes up to about 2.2 g/kg may be used for muscle gain, recovery, or dieting. Needs vary with age, activity level, and health status.

What are good sources of protein?

Animal sources include meat, fish, eggs, and dairy. Plant sources include legumes, soy foods, lentils, nuts, seeds, and whole grains.

Does protein help with weight management?

Higher-protein diets can increase satiety and help preserve lean mass during calorie restriction. This can support fat loss when paired with an overall calorie deficit.

Do I need protein supplements?

Not necessarily—many people can meet needs through food. Supplements can be convenient when appetite, schedule, or higher targets make it hard to reach protein goals.

313 science-backed nutrients

3251 sources considered

Evidence-graded information

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313 nutrients total

Vitamin B

Vitamin B1 (Thiamine)

Vitamin B2 (Riboflavin)

Vitamin B3 (Niacin)

Vitamin B5 (Pantothenic Acid)

Vitamin B6 (Pyridoxine)

Vitamin B7 (Biotin)

Vitamin B9 (Folic Acid)

Vitamin B12 (Methylcobalamin)

Vitamin B12 (Cobalamin)

Vitamin A & Carotenoids

Vitamin C

Vitamin D

Vitamin E

Vitamin K

Vitaminoids

Trimethylglycine (Betaine)

NMN (Nicotinamide Mononucleotide)

Pyrroloquinoline Quinone (PQQ)

D-Chiro-Inositol

Coenzym Q10 (Ubiquinone)

Betaine HCL

Nicotinamide Riboside

Vitamin B8 (Myo-Inositol)

Choline

Citicoline (CDP-Choline)

Coenzyme Q10 (Ubiquinol)

Calcium

Calcium Alpha-Ketoglutarate

Magnesium

Magnesium Bisglycinate

Magnesium L-Threonate

Trace Minerals

Copper (Bisglycinate)

Chromium Picolinate

Manganese (Bisglycinate)

Zinc

Pentadecanoic Acid (C15:0)

Phosphatidylserine

R-Alpha Lipoic Acid

Black Cumin Oil

Extra Virgin Olive Oil

Ceratiq wheat oil extract

Phospholipids

Algae Oil

Fish Oil

Conjugated Linoleic Acid

Gamma-Aminobutyric Acid

Alpha-Linolenic Acid

Gamma-Linolenic Acid

Omega-3

Docosapentaenoic acid (DPA)

Eicosapentaenoic acid (EPA)

Docosahexaenoic acid (DHA)

AminoMar

Acetyl-L-Carnitine

PABA (para-aminobenzoic acid)

Essential Amino Acids

Conditionally Essential Amino Acids

L-Theanine

Non-Essential Amino Acids

Beta-Alanine

L-Cysteine Hydrochloride

Amino Acid Derivative

Taurine

Creatine (Hydrochloride)

L-Arginine Alpha-Ketoglutarate

Creatine (Monohydrate)

Akkermansia muciniphila

Lactobacillus Reuteri

Probiotics

Bifidobacterium longum BB536

Prebiotics

Stinging Nettle Extract

Pomegranate Polyphenols

Red Beet Extract

Pine Extract (Pycnogenol)

Oligomeric Proanthocyanidins (OPC)

Ashwagandha Root Extract

Methylsulfonylmethane (MSM)

Citrus Sinensis Extract

Horsetail Stem Extract

Flax Seed Extract

Sulforaphane Glucosinolate

Garlic Extract

Black Pepper

Apricot Kernel Extract

Lovage

Spiny Rest Harrow Root Extract

Juniper Berry Extract

Bearberry Leaf Extract

White Kidney Bean Extract

Lady’s Mantle Extract

Bitter Orange Extract

St. John’s Wort Extract

Japanese Knotweed Extract

Hydroxytyrosol/tyrosol

Olive extract

Sesame seed lignan extract

Broccoli Sprout Extract

Cranberry Extract

Flavon Glycosides

Gentian Root Extract

Griffonia simplicifolia Extract

Ajuga Turkestanica Extract

Amaranthus Leaf Extract

Banaba Extract

Boswellia Extract

Capsaicin

Cayenne Pepper Extract

Celery Extract

Ceylon Cinnamon Extract

Chamomile Extract

Charantin

Chinese Goldthread Root Extract

Citrus Aurantium Extract

Cocoa Extract

Cyanotis Arachnoidea Extract

Fadogia Agrestis Extract

Garcinia Cambogia Extract

Goldenrod Extract

Green Tea Extract

Guarana Extract

Horse Chestnut Extract

Grapefruit Seed Extract

Grape Vine Leaf Extract

Green Tea Polyphenols

Epigallocatechin Gallate (EGCG)

Adaptogens

Cordyceps sinensis extract

Ginsenoside

Lion's Mane (Hericium erinaceus)

Ginseng Extract

Cat's Claw (Uncaria tomentosa)

Arjuna (Terminalia arjuna)

Tribulus Terrestris Extract

Rhodiola rosea

Panax Ginseng Extract

Mushrooms

Reishi Extract

Astragalus Polysaccharides

Hyaluronic Acid

Glucosamine Sulfate

Chondroitin Sulfate

Glucosamine Sulphate 2KCL

Protein

Strong study situation·10/10

A higher score indicates better study conditions, but not necessarily effectiveness.

Protein is an essential macronutrient required for muscle repair, metabolism, and overall health.

Muscle Repair Essential Nutrient Muscle Gain Bone Health Weight Management

dose range

0.8–2.2 g/kg body weight

Divided into 2–5 doses per day, such as with meals and/or post-workout.

Consumption

Can be consumed through a variety of foods (meats, dairy, eggs, legumes) or through supplements (whey, casein, plant-based powders).

Not fat-soluble.

Best time

Post-workout intake is beneficial for muscle repair; spreading intake evenly across meals supports absorption and muscle protein synthesis.

Description

Protein is made up of amino acids and is crucial for building and maintaining muscles, supporting immune function, and producing enzymes and hormones. It is found in both animal and plant-based foods, and is often supplemented by athletes or those with higher needs.

benefits

Main effects with level of evidence

Strong

Note on evidence

There is robust evidence from randomized trials and meta-analyses supporting the benefits of protein for muscle health, weight management, and bone strength, especially when intake meets or exceeds the RDA in active individuals.

Supports Muscle Growth and Repair

Strong

Supplemental protein increases muscle protein synthesis, aiding in muscle development and post-exercise recovery, especially when combined with resistance training.

Particularly relevant for: athletes · older adults · active individuals

1 · PubMed Meta-analysis: Protein Supplements and Muscle Strength 5 · Examine.com: Protein

Promotes Satiety and Supports Weight Management

Strong

Higher protein diets help reduce appetite, preserve lean mass, and support fat loss during caloric restriction.

Particularly relevant for: individuals seeking weight loss · overweight individuals

2 · NIH ODS: Dietary Supplements for Weight Loss 4 · NIH ODS: Protein Fact Sheet for Health Professionals 5 · Examine.com: Protein

Maintains and Supports Bone Health

Moderate

Adequate protein intake is linked to greater bone mineral density and a lower risk of fractures in adults, especially older adults.

Particularly relevant for: older adults

3 · PubMed: Protein Intake and Bone Health in Adults 4 · NIH ODS: Protein Fact Sheet for Health Professionals

Essential for Enzyme and Hormone Production

Strong

Protein supplies amino acids required for enzyme and hormone synthesis, which are critical for metabolism and physiological regulation.

Particularly relevant for: all

4 · NIH ODS: Protein Fact Sheet for Health Professionals 7 · Academy of Nutrition and Dietetics: Protein

Safety & Information

Important safety information & known risks

For educational purposes only • not medical advice

Protein is safe when consumed in recommended amounts by healthy adults; specific populations should avoid very high intakes.

warning notices

Digestive issues (bloating, constipation) are possible, particularly with rapid increases or certain protein types (e.g. whey).
Those with pre-existing renal disease should consult healthcare providers before increasing protein intake.
No evidence supports that typical protein supplementation harms healthy kidneys.
Avoid excessive protein intake (>2.5 g/kg/day) if you have kidney disease or reduced renal function.
Consult a healthcare provider before using protein supplements if pregnant, breastfeeding, or under medical supervision for chronic disease.
Monitor for potential digestive discomfort such as bloating or constipation when starting protein supplements.

Known interactions with medications

levodopa
ACE inhibitors

Contraindications / special precautions

kidney disease
chronic renal insufficiency

interactions

Important interactions between active ingredient ↔ supplement / medication / food

Protein can interact with certain drugs and dietary components, potentially affecting absorption or metabolic handling.

Protein can interfere with absorption of Levodopa (used in Parkinson’s disease).

drug · Levodopa

SeparateModerateSeparate by 1–2h

Why

Dietary protein competes with Levodopa for transport across the gut and blood-brain barrier.

recommendation

Take Levodopa at least 30 minutes before or 1–2 hours after high-protein meals.

4 · NIH ODS: Protein Fact Sheet for Health Professionals

High protein intake may affect kidney function in those on certain blood pressure medications.

drug · ACE inhibitors

MonitorLimited

Why

Some antihypertensive drugs (ACE inhibitors, ARBs) can affect renal function, as can excessive dietary protein.

recommendation

Regularly monitor kidney function tests if consuming high-protein diets while on these medications.

4 · NIH ODS: Protein Fact Sheet for Health Professionals

mechanisms of action

Brief explanations of how it works

Stimulates Muscle Protein Synthesis

Protein provides essential amino acids required to rebuild and repair muscle fibers, especially following exercise. Leucine, in particular, acts as a key trigger for muscle protein synthesis.

1 · PubMed Meta-analysis: Protein Supplements and Muscle Strength 5 · Examine.com: Protein