Supplement Onset Timeline

See how long common supplements typically take to show an effect in clinical trials, from melatonin's minutes to calcium's months.

Bars show the typical range in trials, on a log scale.
1 h1 day1 wk1 mo3 mo1 yr
L-Theanine30 min – 60 min
Melatonin30 min – 60 min
Psyllium fiber12 h – 3 days
Zinc1 day – 7 days
Echinacea1 day – 7 days
Elderberry1 day – 5 days
Probiotics3 days – 4 weeks
Rhodiola3 days – 4 weeks
Creatine7 days – 4 weeks
Vitamin C7 days – 4 weeks
Magnesium2 weeks – 8 weeks
Vitamin B122 weeks – 8 weeks
Iron2 weeks – 13 weeks
Valerian2 weeks – 4 weeks
NMN / NR2 weeks – 9 weeks
Omega-3 (EPA/DHA)4 weeks – 12 weeks
CoQ104 weeks – 12 weeks
Folic acid4 weeks – 13 weeks
Berberine4 weeks – 13 weeks
Turmeric / curcumin4 weeks – 12 weeks
Glucosamine4 weeks – 12 weeks
St. John's wort4 weeks – 6 weeks
Ginkgo4 weeks – 12 weeks
Green tea extract4 weeks – 12 weeks
Garcinia cambogia4 weeks – 12 weeks
Red yeast rice4 weeks – 12 weeks
Potassium4 weeks – 8 weeks
Ashwagandha6 weeks – 8 weeks
Vitamin D38 weeks – 13 weeks
Collagen peptides8 weeks – 12 weeks
Biotin8 weeks – 4 months
Vitamin K213 weeks – 12 months
Calcium6 months – 12 months
Lutein & zeaxanthin (AREDS2)6 months – 12 months

Onset depends on dose, your starting levels and what's being measured. Many supplements only help people who are deficient.

Sources

  1. NIH Office of Dietary Supplements: Fact sheets

Free tool for education only. It doesn't replace advice from your doctor or pharmacist.

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