# What Causes Skin to Age? Intrinsic and Extrinsic Factors Explained

> The science of skin aging: intrinsic (genetic, hormonal) versus extrinsic factors like sun, pollution, smoking, diet and sleep, and which ones you can control.

Canonical: https://antiagingcare.org/blog/what-causes-skin-to-age
HTML version: https://antiagingcare.org/blog/what-causes-skin-to-age
Author: Anti Aging Care Editorial Team
Published: 2025-10-21
Updated: 2026-10-24
Category: Science

Skin ages for two broad reasons: intrinsic aging, driven by time, genetics and hormones, and extrinsic aging, driven by the environment and habits. The short answer: sun exposure is the biggest factor you can control, followed by smoking. Researchers group environmental influences into the "skin aging exposome," which includes sun radiation, air pollution, tobacco smoke, nutrition and other lifestyle factors ([Krutmann et al., *J Dermatol Sci*, 2017](https://pubmed.ncbi.nlm.nih.gov/27720464/)).

## Intrinsic aging

- **Genetics:** influence skin type, thickness and how early lines appear.
- **Cellular changes:** skin cells divide more slowly and repair less efficiently.
- **Collagen and elastin decline:** the skin's support proteins diminish; enzymes called matrix metalloproteinases break them down.
- **Hormones:** falling estrogen around menopause is linked to drier, thinner skin.

MedlinePlus describes aging skin as thinner, paler and more translucent, with reduced strength and elasticity ([MedlinePlus](https://medlineplus.gov/ency/article/004014.htm)).

## Extrinsic aging

| Factor | Effect | What helps |
|---|---|---|
| UV radiation | Wrinkles, spots, leathery texture | Daily sunscreen, shade |
| Smoking and vaping exposure | Wrinkles, dullness | Quitting |
| Air pollution | Linked to pigment spots | Cleansing, sunscreen, antioxidants |
| Poor sleep | Tired appearance | Consistent sleep |
| Diet high in sugar | May contribute via glycation | Balanced diet |
| Alcohol | Dehydration, redness | Moderation |

The AAD notes that sun protection and not smoking are among the most effective ways to prevent wrinkles ([AAD: wrinkle remedies](https://www.aad.org/public/everyday-care/skin-care-secrets/anti-aging/wrinkle-remedies)).

## Why sun matters most

In a randomized trial, people assigned daily sunscreen showed no detectable increase in skin aging over 4.5 years, unlike those who used it at their discretion ([Hughes et al., *Ann Intern Med*, 2013](https://pubmed.ncbi.nlm.nih.gov/23732711/)).

## Genetics vs lifestyle

You can't change genes, but lifestyle has a big influence on how skin looks. People of similar age can look very different depending on sun and smoking history.

## Ethnicity and skin type

Darker skin has more epidermal melanin, making it more vulnerable to uneven pigmentation, while a thicker dermis makes lines less noticeable ([Vashi et al., *J Clin Aesthet Dermatol*, 2016](https://pubmed.ncbi.nlm.nih.gov/26962390/)).

## Common myths

- *Makeup ages skin:* not by itself; sleeping in makeup or skipping cleansing can irritate.
- *Working out ages your face:* there's no good evidence; exercise supports overall health.
- *Coffee ages skin:* evidence doesn't show this in moderate amounts.

## What you can do

1. Daily broad-spectrum sunscreen
2. Don't smoke
3. A retinoid to treat existing photoaging ([Weiss et al., *JAMA*, 1988](https://pubmed.ncbi.nlm.nih.gov/3336176/))
4. Sleep, balanced diet and moderate alcohol

## Frequently asked questions

**What's the number one cause of skin aging?** For most people, sun exposure.

**Can you reverse skin aging?** You can improve sun damage with retinoids and procedures, not stop aging.

**Do some people age slower?** Yes, due to genetics, skin type and especially sun habits.

_This article is for educational purposes only and is not medical advice. Talk to a board-certified dermatologist about your situation._

## Sources

- Krutmann J et al. The skin aging exposome. *J Dermatol Sci*. 2017. [PubMed](https://pubmed.ncbi.nlm.nih.gov/27720464/)
- MedlinePlus. [Aging changes in skin](https://medlineplus.gov/ency/article/004014.htm)
- American Academy of Dermatology. [Wrinkle remedies](https://www.aad.org/public/everyday-care/skin-care-secrets/anti-aging/wrinkle-remedies)
- Hughes MC et al. Sunscreen and prevention of skin aging: a randomized trial. *Ann Intern Med*. 2013. [PubMed](https://pubmed.ncbi.nlm.nih.gov/23732711/)
- Vashi NA et al. Aging differences in ethnic skin. *J Clin Aesthet Dermatol*. 2016. [PubMed](https://pubmed.ncbi.nlm.nih.gov/26962390/)
- Weiss JS et al. Topical tretinoin improves photoaged skin. *JAMA*. 1988. [PubMed](https://pubmed.ncbi.nlm.nih.gov/3336176/)