PepCue vs LynkDose.
LynkDose and PepCue look at the same dose from opposite ends. LynkDose is built for people who want to see what a compound is doing in their own body. It reads sleep, heart rate, heart rate variability, glucose, body fat and more from Apple Health, accepts uploaded lab results, and lines all of it up against the dose log, with an AI assistant that can read the whole picture. PepCue asks what controlled studies in other people have shown. Both are reasonable questions. They are not the same question, and neither answer substitutes for the other.
Last checked September 2026. Competitor features and pricing change, so verify on their own site or App Store listing before you decide.
You want to know what the published human evidence says about a compound before you start, graded on a model you can read, and you want tracking and calculators that cost nothing.
You want your doses lined up against your own biometrics and bloodwork, an AI assistant that knows your logs and inventory, and a compliance score for each compound. LynkDose is built around exactly that. PepCue reads a narrower set from Apple Health, with no glucose or heart rate variability, and does not track lab results at all.
Checked against LynkDose's App Store listing in October 2026, and the features in their column come from that listing. We have not printed a price, rating or review count, and we have not verified where LynkDose stores your logs, so that row is blank.
Side by side, verifiable rows only.
| PepCue | LynkDose | |
|---|---|---|
| Price | Free to use. You can run a full protocol without paying, and there is no subscription gate on logging, schedules, the calculators or the evidence library. | Free to download, with subscription plans sold in the app. Amounts are left off on purpose; check their listing. |
| Account required | Not required. Tracking starts without an account, and the browser calculators need no sign-up either. | Not verified |
| Health app sync | Apple Health on iPhone: with your permission PepCue reads weight, body composition, heart rate, sleep and active energy, and can save logged weight back. Google Health Connect sync is not advertised. | Apple Health integration reading sleep, heart rate, HRV, glucose, steps, energy, body fat and VO2 max. |
| Lab results | No lab-result or biomarker tracking is advertised, and PepCue does not interpret results. | Lab results can be uploaded and lined up against dose logs. |
| AI assistant | PepCue AI, an in-app assistant, answers questions about what you have logged. A safety filter turns away dosing, sourcing, diagnosis and medical-advice questions before they reach the model. | Yes, an AI assistant aware of your logs, inventory and biometrics. |
| Vial inventory | Enter a vial's strength, diluent volume, price and expiry, and each logged dose draws it down, reporting remaining doses and days of supply. | Inventory across unreconstituted, reconstituted and pre-mixed stock, with low-stock and expiry alerts. |
| Adherence | Adherence and timing accuracy charted from what you logged. | A compliance score for each compound, as a percentage of scheduled doses completed. |
| Injection sites | A body map records each injection site, shades recent ones and scores how evenly they are spread. It does not advise where to inject. | A full-body heatmap of injection sites. |
| Evidence grading | Every compound carries an S to F evidence tier scored on six axes: human evidence, preclinical depth, mechanism confidence, safety clarity, regulatory clarity and practical relevance. | Not verified |
| Scoring model published | Yes. The full six-axis model, the tier thresholds and a worked example on a real compound are published on the methodology page. | Not verified |
| Citations | 306 cited sources across 69 compound profiles, plus a generated research index of 274 unique PubMed records, every one pulled from NCBI and re-resolved against live PubMed by an audit script kept in the repo. | Not verified |
| Affiliate codes or vendor rankings | None. PepCue sells no peptides, ranks no vendors, takes no kickbacks and places no affiliate codes. | Not verified |
| Dosing guidance | Never. PepCue explains compounds and does the arithmetic on numbers you enter. It does not tell anyone what to take. | Not verified |
| Where your data lives | Protocols, doses, inventory, weights and check-ins are stored on your device rather than on our servers. | Not verified |
What PepCue does differently.
A personal correlation and a controlled trial answer different questions, and the difference is worth being precise about. If your heart rate variability rises in the weeks after you start a compound, that is real information about you. It cannot tell you whether the compound caused it, because sleep, training, diet, season and expectation all moved in the same weeks. A placebo-controlled trial exists to separate those things, which is why it is slow, expensive and rare for most compounds in this category.
PepCue is built around that second kind of evidence. Every compound carries an S to F tier computed from six scored axes: human evidence, preclinical depth, mechanism confidence, safety clarity, regulatory clarity and practical relevance. The model, its thresholds and a worked example are published, so a grade can be challenged on specifics. Where the human evidence is zero, the tier says so, which is context a personal trend line cannot supply by itself.
Across 69 profiles there are 306 cited sources, and a generated research index of 274 unique PubMed records is pulled from NCBI and re-resolved against live PubMed by an audit script kept in the repo. Safety clarity scores how well a safety profile is known rather than how safe a compound is, so a compound with no human toxicology data sits at the floor. One person's normal bloodwork is reassuring for that person; it does not fill that gap.
The practical layer is free. Tracking needs no account and no subscription, the 9 calculators run in a browser with no install, and logs stay on your phone. There are no affiliate codes, no vendor rankings and no dosing guidance anywhere on PepCue.
Where LynkDose is stronger.
LynkDose does something PepCue does not attempt: it puts your own physiology next to your log. If you wear a device that records sleep, heart rate variability or glucose, LynkDose reads that from Apple Health and lines it up against what you took and when. PepCue reads weight, body composition, heart rate and sleep from Apple Health, but not glucose or heart rate variability, and it is not built around lining your physiology up against each dose. That comparison mostly happens in your head.
Lab results are the same story. Uploading bloodwork and seeing it against months of dose history is a genuinely useful thing to bring to a clinician, and PepCue does not track labs at all. LynkDose's AI assistant can see logs, inventory and biometrics together. PepCue AI also reads your log, but its scope is narrower and it turns away dosing and diagnosis questions by design.
The bookkeeping is also more granular than most. LynkDose separates unreconstituted, reconstituted and pre-mixed stock, and scores compliance per compound as a percentage of scheduled doses. If you run several compounds and want the accounting that detailed, that is a real advantage.
Used together, the two are complementary rather than redundant. One shows what happened in you; the other shows what has been demonstrated in controlled studies. The PepCue library and calculators need no account, so reading a grade costs nothing even if your log lives in LynkDose.
FAQ.
Can LynkDose tell me whether a peptide is working?
It can show you how your biometrics and labs moved alongside your doses, which is useful. A personal trend cannot by itself separate the compound from everything else that changed at the same time. That is what controlled trials are for, and it is what PepCue's evidence grade summarises.
Does PepCue sync with Apple Health like LynkDose?
Partly. On iPhone, PepCue reads weight, body composition, heart rate and sleep from Apple Health and can save weight back, but it does not read glucose or heart rate variability and does not track lab results. If biometric correlation is what you want, LynkDose is built for it.
Is LynkDose free?
LynkDose is free to download and sells subscription plans in the app. We have not printed its prices because they change; check their listing. PepCue is free to use, with no subscription gate on logging, schedules or the calculators.
Can I use both?
Yes. LynkDose for the personal data layer, PepCue for the published evidence and the free calculators. The PepCue library needs no account, so nothing has to move.
Last checked September 2026. Competitor features and pricing change, so verify on their own site or App Store listing before you decide.