Methodology
Where the Numbers Come From
Every number in the Doseline database has a source. Here’s how we evaluate and rank them.
Evidence Hierarchy
Not all data is equal. A half-life pulled from an FDA prescribing label carries more weight than one extrapolated from an animal study. We use a four-tier system to communicate the quality of each medication’s pharmacokinetic data.
| Tier | Source Type | What It Means |
|---|---|---|
| Tier A | FDA / EMA Labels | Official prescribing information from regulatory agencies. Gold standard. These numbers come from large, well-controlled clinical trials submitted for drug approval. |
| Tier B | Published Clinical Data | Peer-reviewed studies and clinical trials indexed on PubMed. Solid evidence, sometimes from smaller sample sizes or specific populations. |
| Tier C | Clinical Guidelines | Expert consensus documents, case studies, and clinical guideline publications. Good practice-level evidence, but not always backed by controlled trials. |
| Tier D | Community / Estimates | Animal studies, pharmacological estimates derived from ester analogies, and community-reported data. Useful but treat with appropriate caution. |
How We Assign Tiers
Each medication in the database has a data quality rating. This rating reflects the best available source for its core pharmacokinetic parameters: half-life, time to peak (Tmax), and bioavailability.
A medication with an FDA label gets Tier A even if we also reference community data for practical tips (like optimal injection sites or reconstitution advice). The tier describes the pharmacokinetic confidence, not the overall information quality.
When multiple sources exist, we prefer the most rigorous one. If an FDA label and a PubMed study report slightly different half-lives, we use the FDA label but note the discrepancy.
Per-Category Sourcing
The quality of available data varies significantly by medication category. Here’s the landscape:
GLP-1 Medications
Primarily Tier A. Semaglutide, tirzepatide, liraglutide, and dulaglutide all have extensive FDA/EMA approval data with detailed PK profiles from large clinical trials (SUSTAIN, SURPASS, STEP programmes). This is the best-studied category in our database.
Testosterone & HRT
Mix of Tier A and Tier B. Testosterone cypionate, enanthate, and undecanoate have FDA-approved labels with published PK data. Estradiol valerate and cypionate are similarly well-documented. Some less common esters and formulations rely on older clinical literature or pharmacological extrapolation from related compounds.
AAS (Anabolic-Androgenic Steroids)
Tier B–C. Many AAS have older clinical data from when they were prescribed more broadly. Some compounds (like trenbolone) were developed for veterinary use and lack human clinical trials entirely. We use available pharmacological literature and ester-based extrapolation where necessary, and we’re upfront about it.
Peptides & Wellness
Mostly Tier C–D. Research peptides like BPC-157, TB-500, and GHK-Cu have limited human PK data. Much of what exists comes from animal studies, in-vitro research, or community-reported experiences. We include these compounds because the community uses them, but we flag the data quality clearly. You should know what you’re working with.
Transparency Is the Point
Every medication profile page in Doseline shows its sources with links where available. The data quality tier is visible on the page and in the app. We don’t hide uncertainty behind a clean UI — we surface it.
If you find an error, a better source, or a missing citation, we genuinely want to know. The database improves when the community contributes.