See how a dose fades over time.
Pick a compound or enter your own half-life and watch the curve. Add a dosing interval to see accumulation toward steady state. A simplified, population-average model for education only — not a measured level, and never a dose recommendation.
| Half-lives | Elapsed | % remaining |
|---|---|---|
| 1× t½ | 7 d | 50.0% |
| 2× t½ | 14 d | 25.0% |
| 3× t½ | 21 d | 12.5% |
| 4× t½ | 28 d | 6.3% |
| 5× t½ | 35 d | 3.1% |
Lumara is a tracking tool and does not provide medical advice, diagnosis, or treatment. This is a simplified, single-compartment, population-average model — an educational estimate, not a measured blood level — and it never recommends a dose. Always follow your provider's guidance.
In the Lumara app you add your medication and log each dose. This calculation stays on this page.
The math stays here. The doses go in the app.
This calculator runs in your browser and saves nothing. In the Lumara app you log each dose your provider set, get reminders that fire on time, and in Premium track vial supply and use-by dates.
Free to download for iPhone & Android. Logging stays free for good; a 7-day trial of Premium runs in the app — no card. Tracking & education only, never a dose recommendation.
How to read a half-life decay curve
A half-life is the time for the amount in your body to fall by half. In a simple single-compartment model, each half-life halves what remains, so the curve drops quickly at first and then flattens.
- Pick a compound from the cited list, or enter your own half-life.
- Read the decay curve to see how much remains at each point after a dose.
- Add a dosing interval to overlay accumulation toward steady state across repeated doses.
- Treat it as a model — it shows the shape of decay, not your actual blood level.
Worked example: a 100 unit dose with a 24-hour half-life
Starting from 100 units of “amount in body,” with a 24-hour half-life:
- At 24 h — half remains: 50 units.
- At 48 h — half of that: 25 units.
- At 72 h — 12.5 units, and so on.
- Steady state — with regular dosing, levels plateau after roughly 5 half-lives.
This is a population-average model, not a measured level — individual metabolism, absorption, and ester kinetics vary. Enter your own compound and interval above.
Sources
- Hallare J, Gerriets V. Elimination Half-Life of Drugs. [Updated 2025 May 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Bookshelf ID: NBK554498. PMID: 32119385.
- OZEMPIC (semaglutide) injection, for subcutaneous use. Full prescribing information, section 12.3 Pharmacokinetics (Elimination). Novo Nordisk; revised 5/2026. DailyMed.
- DEPO-TESTOSTERONE (testosterone cypionate injection, USP) CIII. Prescribing information, Clinical Pharmacology: Pharmacokinetics. Pharmacia & Upjohn Company LLC (Pfizer); LAB-0245-17.0, revised September 2025. DailyMed.
Frequently asked questions
A half-life is the time it takes for the amount of a substance in your body to drop by half. After one half-life, 50% remains; after two, 25%; after three, 12.5%, and so on. It sets how quickly a dose clears and how doses accumulate with repeated use.
Steady state is when the amount you take each interval balances the amount your body clears, so levels plateau. With regular dosing it is reached after roughly five half-lives — which is why some protocols take weeks to “settle in.”
No. This is a simplified single-compartment, population-average model that shows the shape of decay and accumulation. Real levels depend on your metabolism, absorption, and the specific ester or formulation, and can only be known by a blood test.
No. It is an educational visualization. It never recommends a dose or interval. Always follow your licensed provider’s instructions.