PAG LABS Research Library — Skin Longevity Science

This is the PAG LABS evidence hub for skin aging, photoaging, NAD+ biology, cellular senescence, collagen remodeling and nutritional research.

The purpose of this library is not to prove that one ingredient “reverses aging.” It is to map what scientists know, what remains uncertain and which findings actually come from human studies.

The studies, side by side

Start with the exact ingredient and the outcome. This selected evidence map brings together human skin research, biomarker trials and supporting delivery science. It is a curated starting point, not a systematic review or a set of trials of PAG NAD CORE.

Doses describe the cited research, not personal dosing instructions. A population observation, an uncontrolled study and a randomized trial have different strengths. Full methods and disclosures are available in the linked publications.

Start here

• Photoaging vs Intrinsic Skin Aging — the foundational distinction between chronological change and UV-driven aging.
• How to Reduce Wrinkles Naturally — a practical hierarchy of interventions by human evidence.
• The 500 Dalton Rule — what skin penetration does and does not tell you about topical efficacy.
• NAD+ for Skin — direct NAD+ vs NR and NMN, with biomarkers separated from skin outcomes.
• Anti-Aging Supplements for Skin in 2026 — collagen, NAD+, quercetin and resveratrol ranked by evidence type.

Choose your next step

• NAD+ vs NMN vs NR: identify the form
• NAD+ vs niacinamide: compare the routes
• Choose a NAD+ supplement
• How long does NAD+ take to work?

Evidence legend

Level	What it means
Human clinical	Measured clinical outcomes in people, ideally randomized and controlled.
Human biomarker	A biological marker changed in people, but a visible skin benefit was not necessarily demonstrated.
Mechanistic	Explains a biological pathway in cells or tissues.
Preclinical	Cell or animal evidence that generates hypotheses for human research.

Evidence level is not a quality score. It tells you how directly a finding applies to the question being asked. A small human trial can be lower quality than a rigorous mechanistic study, but it still answers a more direct human-outcome question.

1. Photoaging and UV exposure

Ultraviolet radiation is one of the best-established extrinsic drivers of visible skin aging. Human research links UV exposure to matrix-remodeling signals including MMP-1, and randomized evidence supports regular sunscreen use for slowing photoaging.

Read the randomized sunscreen trial. Then explore Photoaging vs Intrinsic Skin Aging, UV, MMP-1 and Collagen, and the shorter MMP-1 guide.

2. Retinoids and evidence-based topical care

Topical tretinoin has randomized-trial evidence for photoaged skin. That matters because an evidence-first “inside-out” strategy should not pretend proven topical interventions are irrelevant. Nutrition and supplements, where appropriate, are complementary questions—not replacements for photoprotection or dermatologic care.

Review the systematic review of topical tretinoin trials. For delivery and penetration, see The 500 Dalton Rule and Topical vs Oral Skin Aging Interventions.

3. NAD+ biology and skin

NAD+ is central to cellular redox reactions and serves as a substrate for multiple enzyme families. Skin research links NAD biology to cellular energetics, stress responses and aging-related changes. But direct oral NAD+, NR and NMN are different interventions and must be evaluated separately.

Start with NAD+ and Skin Aging: What the Evidence Shows, then read NAD+ for Skin: Direct NAD+, NR and NMN Evidence Explained and Collagen vs NAD+.

4. Cellular senescence and quercetin

Senescent cells and the senescence-associated secretory phenotype are active areas of aging research. Early human senolytic studies have tested drug combinations such as dasatinib plus high-dose quercetin in specific patient populations. These studies do not establish that 250 mg/day of quercetin alone clears senescent skin cells in healthy people.

Read the preliminary dasatinib + quercetin human study, then see Quercetin, Cellular Senescence and Skin.

5. Collagen, extracellular matrix and MMPs

Collagen homeostasis reflects both synthesis and degradation. Matrix metalloproteinases are part of normal tissue remodeling and can be induced by UV-related signaling. Oral collagen research is mixed: pooled analyses often report improvements, while higher-quality or non-industry-funded subsets have sometimes failed to show benefit.

Continue with How Long Does Skin Collagen Remodeling Take?, Collagen vs NAD+, and UV, MMP-1 and Collagen.

6. Resveratrol and polyphenols

Resveratrol has antioxidant and signaling effects in preclinical models and has been studied in several human contexts. Skin-specific evidence is promising but substantially less definitive than marketing language often implies. The source and dose should be described precisely rather than using “wine” as a proxy.

Read Resveratrol and Skin Aging: Promising Biology, Limited Clinical Proof.

7. Population, diet and prevention claims

Population research can generate useful hypotheses, but ethnicity or longevity statistics should not be converted into product efficacy claims. UV behavior, pigmentation, smoking, diet, socioeconomic factors and many other variables can confound comparisons.

See Diet, Sun Exposure and Skin Aging: What Japanese Longevity Research Can Tell Us, Japanese Skin Aging, and Preventive vs Corrective Skincare.

How PAG LABS interprets its own formula

PAG NAD CORE combines direct NAD+, quercetin dihydrate extract and Japanese knotweed extract standardized to 98% resveratrol. We view the formula as a dietary-supplement approach informed by several areas of healthy-aging research. We do not describe it as clinically proven to reverse wrinkles, clear senescent cells, rebuild collagen or reproduce results from NR/NMN trials.

For product-level transparency, view the exact PAG NAD CORE Supplement Facts.

How to read a PAG LABS evidence page

1. Start with the outcome: is the claim about a biomarker, a mechanism or visible human skin?
2. Match the molecule: NAD+, NR and NMN are not interchangeable; neither are quercetin alone and dasatinib + quercetin.
3. Match the route: topical and oral studies cannot be transferred automatically.
4. Match the dose and population: a disease pilot or laboratory dose may not answer a healthy-aging consumer question.
5. Prefer primary human evidence when the claim is clinical: mechanistic evidence is valuable but should stay in its lane.

Research standards

When you read a PAG LABS article, look for a quick answer, an evidence-level explanation, explicit uncertainty, primary references, contextual internal links and a review date. If a claim depends on a precursor, drug combination or non-human model, the article should say so.

Last reviewed: September 26, 2026.

PAG LABS sells dietary supplements. Our Research Library is educational and is not medical advice.