Free calculator
Peptide Half-Life Calculator and Decay Chart
Enter a dose amount, half-life, and elapsed time to see the mathematical remaining amount and decay chart. It does not model individual metabolism or advise a dosing schedule.
This tool does arithmetic on numbers you enter. It does not recommend doses. Talk to your prescriber about your protocol.
Remaining amount over elapsed half-lives
- Percent of dose remaining
- Remaining amount
Results
How it works
Remaining amount = dose amount × 0.5 raised to the power of (time elapsed ÷ half-life)
Every time one full half-life passes, the remaining amount is cut in half
This is arithmetic on the numbers you enter, not a model of absorption or individual metabolism
Worked example
A 1 mg dose with a 24-hour half-life has 0.5 mg remaining after 24 hours, 0.25 mg remaining after 48 hours, and 0.125 mg remaining after 72 hours.
Frequently asked questions
What is a half-life?
A half-life is the time it takes for half of a substance to be eliminated. After one half-life, half the dose remains mathematically; after two half-lives, a quarter remains, and so on.
Where do I find a peptide’s half-life?
This calculator does not supply a half-life value for you. Use a published reference for the specific compound, such as a package insert or a peer-reviewed pharmacokinetic study, and enter that number above.
Does the remaining amount tell me when to take my next dose?
No. This calculator only computes a mathematical remaining amount from the dose, half-life, and time you enter. It does not recommend, adjust, or suggest a dose or a schedule.
Why does the remaining amount never reach zero?
Exponential decay approaches zero without ever mathematically reaching it. After enough half-lives, the remaining amount becomes very small but the formula never returns exactly zero.
Does Peptisy give medical advice?
No. Peptisy performs arithmetic on the numbers you enter. It does not recommend, adjust, or suggest a dose. Talk to your prescriber about your protocol.
This tool does arithmetic on numbers you enter. It does not recommend doses. Talk to your prescriber about your protocol.