Whey protein
Supplement
protein
fitness
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Muscle mass with resistance training · meeting daily protein
When to take
Before or after training both count · doses every 3–4 h
Take with
Water · whey is water soluble, mixes easily, digests fast
Pros & cons
Pros
- Top leucine of common proteins (11%) · fast digested
- ISSN: 20–40 g per dose, 1.4–2.0 g/kg a day for most
- NIH ODS: optimises training response and recovery
Cons
- Most trials: no extra max-strength gain over diet alone
- Whole foods can meet needs · powder is convenience
- A milk protein · lactose and fat vary with filtration
Sources
- NIH ODS — Dietary Supplements for Exercise and Athletic Performance (Health Professional), Table 1 protein row · read 2026-08-27
what it says
“Optimizes muscle training response during exercise and subsequent recovery period … No safety concerns reported at daily recommended intakes for athletes of up to about 2.0 g/kg body weight”
- NIH ODS — Exercise and Athletic Performance fact sheet, introduction (athlete protein needs) and BCAA section (whey leucine) · read 2026-08-27
what it says
“protein (0.55 to 0.9 g/lb body weight [1.2 to 2.0 g/kg body weight]) … protein powders made from complete proteins, especially whey, which has more leucine than either casein or soy”
- NIH ODS — Exercise and Athletic Performance fact sheet, timing statement · read 2026-08-27
what it says
“it is not clear from existing research whether consumption of protein and BCAAs before versus after a workout affects their ability to maximize muscle protein synthesis”
- ISSN position stand: protein and exercise (Jäger et al., JISSN 2017) — position statement 2 · read 2026-08-27
what it says
“For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals”
- Jäger et al., JISSN 2017 — position statements 5 and 7 (per-dose amount, distribution) · read 2026-08-27
what it says
“General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20–40 g … These protein doses should ideally be evenly distributed, every 3–4 h, across the day”
- Jäger et al., JISSN 2017 — position statement 8 (timing) · read 2026-08-27
what it says
“The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion”
- Jäger et al., JISSN 2017 — milk proteins section (whey vs casein leucine) · read 2026-08-27
what it says
“Milk proteins have undergone extensive research … Comparison of the quality of whey and casein reveal that these two proteins routinely contain the highest leucine content of all other protein sources at 11% and 9.3%, respectively”
- Jäger et al., JISSN 2017 — whey solubility/digestion and filtration (lactose, fat) · read 2026-08-27
what it says
“Whey protein is water soluble, mixes easily, and is rapidly digested … producing an electric charge on the proteins that can be used to separate them from lactose and fat”
- Jäger et al., JISSN 2017 — supplemental protein and maximal strength · read 2026-08-27
what it says
“the effects of supplemental protein consumption has on maximal strength enhancement are varied, with a majority of the investigations reporting no benefit”
- Jäger et al., JISSN 2017 — position statement 9 (whole foods vs supplements) · read 2026-08-27
what it says
“While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity”
- Jäger et al., JISSN 2017 — protein safety section (renal failure) · read 2026-08-27
what it says
“people in renal failure benefit from protein-restricted diets, but extending this pathophysiology to otherwise healthy exercise-trained individuals who are not clinically compromised is inappropriate”
- Jäger et al., JISSN 2017 — protein safety section (high-intake trials) · read 2026-08-27
what it says
“controlled investigations spanning up to one year in duration utilizing protein intakes of up to 2.5–3.3 g/kg/day in healthy resistance-trained individuals consistently indicate … no harmful effect on blood lipids or markers of kidney and liver function”
- FDA — Daily Value on the Nutrition and Supplement Facts Labels, Reference Guide: Daily Values for Nutrients (content current as of 03/05/2024) · read 2026-08-27
what it says
“DVs are the recommended amounts of nutrients to consume or not to exceed each day … Protein 50g”
- HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (Oct 2025) · read 2026-08-27
what it says
“The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list [whey / milk protein not listed in Annex A or B]”
- iHerb Singapore — Whey Protein category (SG$ pricing, default order) · read 2026-08-27
what it says
“California Gold Nutrition, Sport, Whey Protein Isolate, Unflavored … Optimum Nutrition, Gold Standard® 100% Whey Protein, Double Rich Chocolate … Dymatize, ISO100® Hydrolyzed, 100% Whey Protein Isolate … Thorne, Whey Protein Isolate, Chocolate … RYSE, Loaded Protein, Skippy® Peanut Butter”
Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.