Supplement Timing Calculator

Build a personalised supplement schedule. Enter which supplements you take and your wake, sleep, and workout times, get evidence-based timing recommendations for each.

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Supplement Timing Calculator visual guide — Save this guide, pin it for later.

Why Timing Matters (For Some Supplements)

Supplement timing is one of the most confusing topics in nutrition, partly because it matters significantly for some supplements and almost not at all for others. Understanding which category each supplement falls into lets you prioritise what actually makes a difference.

High-Timing-Sensitivity Supplements

Pre-workout: 30–60 minutes before exercise for peak caffeine levels during the session
Berberine: Before carbohydrate-heavy meals, acts on glucose uptake pathways
Casein protein: Before sleep, slow digestion provides overnight amino acid availability
Magnesium: Evening, nervous system calming effect best used before sleep

Low-Timing-Sensitivity Supplements

Creatine: Take consistently daily. Post-workout is slightly optimal on training days but the difference is small.
Vitamin D: Any time with a fat-containing meal. Morning preferred for potential sleep quality reasons.
Omega-3: With any fat-containing meal for absorption. Timing between meals has negligible difference.
Collagen: Pre-exercise with vitamin C shows the best evidence for tendon/joint health.

Frequently Asked Questions

Does supplement timing really matter?

It depends on the supplement. For some, timing is critical: pre-workout needs 30–60 minutes before exercise; berberine works best taken before carbohydrate-heavy meals; magnesium is most effective at night. For others, consistency matters far more than timing: creatine produces the same results whether taken morning, post-workout, or evening, daily consistency is what matters. The calculator identifies which supplements are timing-sensitive and optimises your schedule accordingly.

What is the best time to take creatine?

On training days, post-workout with protein and carbohydrates may slightly improve creatine uptake into muscles. On rest days, any time of day is fine, take with a meal. The most important thing about creatine timing is that you take it every single day, including rest days. Missing days disrupts muscle creatine saturation.

When should I take vitamin D?

Vitamin D is fat-soluble and should be taken with a fat-containing meal for optimal absorption. Morning (with breakfast) is generally preferred, as some research suggests evening vitamin D can affect sleep quality by influencing melatonin pathways. Take with the meal that contains the most fat in your morning routine.

Can I take all my supplements at once?

Some supplements should not be combined: iron and calcium compete for absorption (separate by 2+ hours); zinc and iron compete; magnesium can interfere with iron absorption. Fat-soluble vitamins (A, D, E, K) should all be taken with food. Water-soluble vitamins (B complex, C) can be taken any time. The safest approach is to take performance supplements around training, health supplements with breakfast/dinner, and sleep supplements at bedtime.

How it's calculated: this tool uses established, published equations. See the full calculator methodology for the formulas and assumptions behind it.

Results are estimates for general guidance, not medical advice. See our disclaimer, and speak to a qualified healthcare professional before making medical or dietary changes.