This is the one format we will tell you to skip outright. Not because the companies are dishonest, but because skin is very good at its job and the molecules involved are the wrong shape to get through it.
Short version
Transdermal delivery works for a narrow class of molecules: small, fat-soluble, and effective at low doses. NAD+ and its precursors fail all three tests. We are not aware of evidence that patches raise systemic NAD+ meaningfully.
Why skin is a hard barrier
The outermost layer of skin, the stratum corneum, is a dense arrangement of dead cells in a lipid matrix. Its entire biological purpose is keeping things out. Compounds that cross it in useful amounts share a fairly strict profile:
- Small. As a rough rule of thumb, meaningful passive transdermal absorption drops off sharply above roughly 500 daltons.
- Fat-soluble enough to dissolve into a lipid barrier, while still able to leave it on the other side.
- Potent at low doses, because the total amount that can cross a patch of skin is small.
Nicotine, certain hormones and some pain medications fit that profile, which is why those patches exist and work.
Where NAD+ precursors land
| Requirement | NAD+ / precursors | Verdict |
|---|---|---|
| Under ~500 daltons | NAD+ is well above it; precursors are closer but still unfavourable | Fails or marginal |
| Fat-soluble, uncharged | Water-soluble; NAD+ and NMN carry charge | Fails |
| Effective at low dose | Oral protocols use hundreds of milligrams | Fails |
Three out of three in the wrong column. That is why this format does not work, and it is a physics-and-chemistry answer rather than a quality-of-manufacturer answer. A better patch does not fix it.
Our position
Skip it. Of every format on this site, this is the only one where we think the mechanism is not merely oversold but absent at the doses involved. Spend the money on a format that gets the compound into you.
Related: Oral capsules · All six formats