Skin, in evidence order

The telederm subscriptions sell custom formulas at custom billing cycles. The actual evidence hierarchy for skin is older, cheaper, and mostly unpatentable. In order:

1. Sunscreen — the only anti-aging RCT that matters

The Australian randomized trial published in the Annals of Internal Medicine (Hughes et al., 2013) assigned adults to daily sunscreen versus discretionary use for four and a half years — the daily group showed measurably less skin aging. It remains the strongest controlled evidence any "anti-aging" product has ever produced, and it costs about $10. Everything else on this page is downstream of it.

2. Retinoids — the prescription with 35 years of receipts

Topical tretinoin improving photoaged skin was established in controlled trials back in the late 1980s (Weiss et al., JAMA) and the evidence has only compounded. This is what most premium "custom anti-aging formulas" are actually built around. The generic version, with any prescription, runs a fraction of subscription pricing — the math is in our billing-truth table. Over-the-counter retinol is the weaker cousin: same pathway, slower conversion, gentler results.

3. Niacinamide — the credible OTC workhorse

Controlled studies (Bissett et al.) support topical niacinamide for barrier function, texture, and the appearance of fine lines and blotchiness. Effects are real and modest, the ingredient is cheap, and it plays well with everything. A reasonable non-prescription core: sunscreen + niacinamide + retinol.

4. Diet and acne — one place food genuinely shows up

A randomized trial in the American Journal of Clinical Nutrition (Smith et al., 2007) found a low-glycemic-load diet improved acne versus a conventional diet. The dairy signal is weaker and observational. Translation: for acne-prone skin, blood-sugar-spiking eating patterns are a legitimate lever, not an influencer myth — though a modest one next to proven topicals.

5. Sleep, smoking, and the boring multipliers

Smoking's acceleration of skin aging is one of dermatology's most consistent observational findings, and sleep deprivation measurably degrades skin-barrier recovery in small studies. Neither needs a product.

Sources

• Hughes et al., "Sunscreen and Prevention of Skin Aging: A Randomized Trial," Annals of Internal Medicine, 2013 — 24% less skin aging with daily use over 4.5 years.
• Weiss et al., topical tretinoin improves photoaged skin, double-blind vehicle-controlled study, JAMA, 1988.
• Bissett et al., niacinamide and aging facial skin, split-face RCT, Dermatologic Surgery, 2005.
• Smith et al., low-glycemic-load diet and acne, RCT, Am J Clin Nutr, 2007.

Educational content built on the cited literature — not medical advice. Persistent, severe, or scarring skin conditions belong with a dermatologist.