Dosing: why Substrate doesn't give you a number (and what to do instead)

Why this page exists: the most common comment under peptide posts on TikTok and Reddit is a request for a dose — and the numbers that come back are copied from strangers, chosen without any knowledge of the asker's body, medications, or health history. That pattern is one of the most preventable forms of harm in this entire space. Substrate's response is not to compete with the comment section on what number, but to explain why a stranger's number can't be yours.

1. Substrate does not publish doses — on principle

We don't list target doses, "starting points," or titration schedules. Not because we're being cautious for its own sake, but because a dose is a clinical decision about a specific body, and publishing one would be (a) medical advice we're not positioned to give, and (b) an implicit endorsement of use we don't make. The omission is the point. What we can do is teach you why the dose question has no stranger-suppliable answer — and where the real answer lives.

2. Why a stranger's dose can't transfer to you

3. The dose question is the wrong question until you know what's in the vial

The dose someone posts online is a product of variables you don't share with them:

  • Body size and composition — the same "250 mcg" is a meaningfully different dose in a 60 kg body and a 100 kg body.

  • Sex, age, and physiology — these change how a compound is handled.

  • Goal — a dose "for recovery" and a dose "for body composition" aren't interchangeable.

  • Other medications and conditions — interactions and contraindications rewrite what's safe for you (see the self-screen below).

  • The vial itself — and this is the one nobody accounts for: their number assumes their vial actually contains what the label says, at the concentration they think. In a supply where mislabeling is common, the dose is arithmetic built on an unverified premise.


A copied dose silently assumes you match a stranger on every one of these. You don't.

4. Before you dose, screen yourself (a checklist, not a clearance)

A precise dose of an unknown quantity of an unverified compound is not a dose — it's a guess with decimal places. Before "how much," the answerable questions are: what is actually in this vial, at what concentration, and who verified it? If you can't answer those, no dose is meaningful. (This is why the sourcing and purity-vs-potency material isn't a separate topic — it's upstream of every dosing decision.)

This checklist doesn't clear you to use anything. Its job is to make visible how much a copied dose ignored:

  • Medications: what are you currently taking, and has anyone checked it against this compound?

  • Personal/family history that matters for these specific compounds: thyroid cancer or MEN2 (GLP-1 receptor agonists carry a thyroid C-cell warning); any cancer history (BPC-157 / TB-500 are discussed as pro-angiogenic); cardiovascular disease; pregnancy or trying to conceive.

  • Mental health and eating history: appetite-suppressing compounds intersect with disordered eating.

  • The honest one: does the clinician who actually manages your health know you're considering this? If not, why not — and is that reason a good one?

If several of these give you pause, that's not a dosing problem. That's a "this decision needs a professional" signal.

5. What to do instead — route the number to someone who can legitimately give it

The reason people ask strangers is that they expect judgment or a flat "no" from clinicians. Two moves fix that:

  • Bring it up anyway, and bring it up as harm reduction. "I'm already considering / using this; I'd rather do it with your input than without it" is a conversation most clinicians can work with, even ones who'd never initiate it.

  • Use a script if it helps (see the companion "How to talk to your clinician" page). The goal is to move the dosing decision to the one person who has your full clinical picture — which is the only place it can be made responsibly.