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Recovery & HRV

Whey protein

Whey concentrate (~80% protein) or isolate (~90%) — isolate if lactose-sensitive; look for ≥2.5 g leucine per 25 g serving and third-party testing (Informed Sport / NSF)

StrongReal effect, but below wearable noise
3
sources
62
trials
1,863
participants (largest study)
2
study designs
The verdict

Adds 0.30 kg of fat-free mass (95% CI 0.09 to 0.52) and 2.49 kg to 1RM strength (95% CI 0.64 to 4.33) over a training block, and speeds strength recovery at 72 h post-exercise (ES 0.7, 95% CI 0.2 to 1.3).

Why this grade
Emerging
Preliminary or mechanistic
Moderate
Some RCTs, limited replication
Strong
Multiple RCTs or meta-analyses, consistent direction

49 RCTs with 1863 participants, plus a separate recovery meta-analysis, converge on a modest but robust effect with a clear dose-response breakpoint. The honest caveat: whey did nothing for CK or soreness at any timepoint — the benefit is function and mass, not perceived recovery.

How it works

Rapid aminoacidemia with a high leucine fraction triggers mTORC1-mediated muscle protein synthesis; the acute dose threshold for maximal stimulation is ~0.25 g/kg containing 700–3000 mg leucine.

Who it helps, and who it doesn't

Largest gains in resistance-trained and younger adults, and in anyone whose baseline protein intake sits below ~1.6 g/kg/day. Untrained and older adults gained less in the meta-regression.

Measured effects (absolute, from the trials)

Every estimate, against a line of no effect

Diamonds are point estimates; the hairline is the 95% confidence interval where the trial reported one.

  • Fat-free mass gain
    kg · Morton et al., BJSM 2018
    +0.30
    +0.09 … +0.52
  • 1RM strength gain
    kg · Morton et al., BJSM 2018
    +2.49
    +0.64 … +4.33
0+2+4NO EFFECT
Separate scale · effect size
  • Muscle function recovery at 72 h
    effect size · Davies et al., Nutrients 2018
    +0.70
    +0.20 … +1.30
0+0.5+1.0NO EFFECT
Separate scale · effect size (null)
  • Creatine kinase / soreness
    effect size (null) · Davies et al., Nutrients 2018 — no benefit at any timepoint
    0.00
    [not reported]
−0.10+0.1NO EFFECT

Units are never mixed on one line: each scale gets its own axis. Where a trial reported no confidence interval we leave it blank rather than inventing one.

Studies over time

3 studies across 1 years

2017 — 2018
20172018
Meta-analysis or systematic reviewRandomized or crossover trialObservational or preliminaryHover a marker for detail
Dose
20–40 g per serving (0.25 g/kg body mass), enough to hit 1.4–2.0 g/kg/day total protein; benefit plateaus around 1.62 g/kg/day (95% CI 1.03–2.20)
Timing
Anywhere in a 3–4 hourly distribution across the day; pre- or post-workout both work, the 'anabolic window' is at least 24 h wide. 30–40 g casein pre-sleep is the one genuinely time-specific protocol.
Safety flags
  • · Bloating, gas and cramping in lactose intolerance — switch to isolate or hydrolysate
  • · Acne flares are reported with whey in susceptible individuals
  • · No evidence of kidney harm in people with normal renal function, but high intakes are not appropriate in existing chronic kidney disease
Where to buyRecord what I'm taking

References

  1. 1.
    A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults
    British Journal of Sports Medicine · 2018 · meta-analysis · 49 trials · n = 1,863

    FFM +0.30 kg (0.09–0.52), 1RM +2.49 kg (0.64–4.33); benefit plateaued at 1.62 g/kg/day (95% CI 1.03–2.20).

  2. 2.
    The Effect of Whey Protein Supplementation on the Temporal Recovery of Muscle Function Following Resistance Training: A Systematic Review and Meta-Analysis
    Nutrients · 2018 · meta-analysis · 13 trials · n = 152

    Muscle function recovery ES 0.6 (0.1–1.0) at <24 h, 0.4 (0.1–0.8) at 24 h, 0.7 (0.2–1.3) at 72 h; median dose 25 g. No effect on CK or soreness.

  3. 3.
    International Society of Sports Nutrition Position Stand: protein and exercise
    Journal of the International Society of Sports Nutrition · 2017 · systematic review

    1.4–2.0 g/kg/day builds and maintains muscle; acute doses 0.25 g/kg or 20–40 g containing 700–3000 mg leucine; protein every 3–4 h.

Umbral is a wellness product, not a medical device. It does not diagnose, treat, cure or prevent any disease. Supplement information is educational; talk to a clinician before starting anything, especially if you are pregnant, under 18, managing a condition or taking medication.