A 5-question rubric for evaluating cosmetic ingredient science. Post 1: target definition and mechanism. Feedback wanted.

How would you rigorously grade the science behind a cosmetic ingredient claim? Without a scientific background, this has historically been hard. AI makes it more accessible from any chat window, but only if you ask it the right questions.

We're Adipeau, a science-driven skincare company, and we've drafted a 5-question rubric for grading the science behind any cosmetic ingredient claim, used directly or as an AI prompt, on any brand including ours. We're refining it through Reddit feedback before publishing it openly as the standard we hold our own ingredients to.

Part I of the rubric asks: is the target real, and can a cosmetic ingredient engage it? A cosmetic intervention's scientific case is sound when it:

• Names a real biological target

• Shows that modulating it predicts a specific visible change

• Demonstrates that the causal chain to that change holds in humans

• Establishes that an ingredient can engage the target and reach it topically

Part I tests these in sequence. Part II will cover clinical efficacy. A strong case carries an unbroken chain with each link independently supported. A weak one skips steps, asserting the outcome without connecting it back to the target.

Today's post covers question 1 (Q1): target definition and mechanism.

Target: the modulable cellular or tissue state the intervention acts on, named at the level of a state between mediator and outcome (not a single molecule, not the end result). Other terms (skin quality, the evidence ladder) come up in later posts.

Why Q1 matters:

Q1 tests two things: target definition and mechanism specification. The target has to be a modulable cellular or tissue state, not the active molecule (which names a mediator) and not the visible outcome (which names an end result). The mechanism has to be named at the pathway or mediator level, not asserted as a black box. Without both, the case skips steps: it asserts the outcome without connecting back to the target.

Q1, verbatim:

Is there a defined cellular or tissue state, a condition that can be more or less present, that the intervention acts on, named as a state rather than as a molecule (which names a mediator inside the mechanism) or an outcome (which names the end result)? Through what molecular mechanism can that state be modulated, specified at the level of pathway or mediator rather than asserted as a black box, and is each proposed mechanism demonstrated directly, or inferred backward from an observed end-state? Where more than one mechanism is claimed, do they reconcile: same direction on the target state, and physically consistent once conserved quantities (mass, cell number, flux) are tracked. Or do they pull against each other in a way the case must resolve? In what systems and species has each mechanism been demonstrated, and does that evidence cover the intended population? Is the target state present, and the mechanism operative, in the relevant adult human population, not only in developmental, transformed, or rodent-only systems?

What a strong answer looks like:

• Names the target as a specific cellular or tissue state (not the active molecule, not the visible outcome)

• Identifies the mechanism at the pathway or mediator level, distinguishing mechanisms demonstrated directly from those inferred backward from an end-state

• Where multiple mechanisms are claimed, shows they pull in the same direction on the target and are physically consistent once conserved quantities (mass, cell number, flux) are tracked

• Demonstrates the target state and mechanism in the relevant adult human population, not only in developmental, transformed, or rodent-only systems

What a weak answer looks like:

• Names the active molecule and calls that the target, or names the visible outcome (firmer skin, rejuvenation) and calls that the target

• Describes the mechanism as a black box ("supports collagen production") without specifying the pathway

• Lists multiple mechanisms without checking whether they reconcile

• Evidence comes only from in vitro, transformed-cell, or rodent systems, with no demonstration that the same biology operates in the relevant adult human population

We would love to include your feedback into the rubric development. What's not clear? What's missing?