Evidence Based Ingredient Library
This library gives clear, cautious summaries of common supplement ingredients. Evidence can change as new studies are published. A supplement should not replace medical care, a balanced diet, or an appropriate training plan.
Creatine monohydrate
What it is: Creatine helps support the rapid recycling of cellular energy during brief, intense effort.
What the evidence suggests: Creatine monohydrate can improve repeated high intensity performance and can support greater gains from resistance training. A common daily amount is 3 to 5 grams. A loading phase is optional.
Read the complete creatine guide or review the creatine position stand on PubMed.
Protein
What it is: Dietary protein supplies amino acids used to build and repair body tissues.
What the evidence suggests: Adequate protein can support muscle growth and strength when combined with resistance training. Total daily intake matters more than finding a perfect minute to drink a shake.
Use the protein calculator or review the systematic review on PubMed.
Magnesium
What it is: Magnesium is an essential mineral involved in nerve function, muscle function, blood glucose control, blood pressure regulation, and many enzyme reactions.
What the evidence suggests: A supplement can help correct inadequate intake, but benefits depend on a person's diet and status. Supplemental magnesium can cause diarrhea and can interact with some medicines.
Read the NIH magnesium fact sheet.
Vitamin D
What it is: Vitamin D supports calcium absorption and normal bone mineralization. Blood testing is commonly used to assess status.
What the evidence suggests: Supplementation can be useful when intake or blood status is low. More is not always better, and excessive supplemental intake can be harmful.
Read the NIH vitamin D fact sheet.
Probiotics
What they are: Probiotics are live microorganisms that may provide a health benefit when consumed in adequate amounts.
What the evidence suggests: Effects are strain specific. A result found for one organism or dose should not automatically be applied to every probiotic product.
Read the NIH probiotics fact sheet.
Beetroot and dietary nitrate
What it is: Beetroot can provide dietary nitrate, which the body can convert through pathways that support nitric oxide availability.
What the evidence suggests: Some research reports modest benefits for certain endurance efforts, but results vary with the person, dose, exercise, and training status.
Review a systematic review on PubMed.
Lion's mane mushroom
What it is: Lion's mane is an edible mushroom being studied for possible effects on cognition and mood.
What the evidence suggests: Early human studies are interesting, but the evidence is limited and does not establish lion's mane as a treatment for a medical condition.
Review a systematic review on PubMed.
Collagen peptides
What they are: Collagen peptides provide amino acids found in connective tissues.
What the evidence suggests: Collagen and whey are not interchangeable. Whey provides a stronger essential amino acid and leucine profile for stimulating muscle protein synthesis, while collagen is studied more often in connective tissue contexts.
Review the whey and collagen comparison on PubMed.
Safety note
Talk with a qualified medical professional before using a supplement if you take medication, have a health condition, are pregnant or nursing, or are preparing for surgery. Stop using a product and seek appropriate care if you experience a serious reaction.