Does your skin get thicker or thinner as you age?
Your skin thins at two levels with age: that is well established. Retinoid creams have the most support if you want to slow that process; discuss stronger variants (such as tretinoin) with your doctor or dermatologist.
Your skin consists of two layers: the outer epidermis and the deeper dermis (the supportive tissue). Both become thinner as you age. The epidermis loses cells because the number of skin stem cells declines. The dermis loses its firmness as skin cells age and produce progressively less collagen. At the same time, those ageing cells release inflammatory substances that actively break down the skin's structure. This is not mere theory: a meta-analysis of 133 studies across 37 body locations confirms that the epidermis consistently thins with age.
There is one smaller biopsy study (71 people) that found no significant relationship between age and epidermal thickness. That study clearly stands alone against a considerably larger body of evidence pointing in the opposite direction. Worth noting, however, is that the study did find that men have a thicker epidermis than women, and that smoking was associated with a thinner stratum corneum.
The functional consequences are noticeable: the skin barrier works less effectively, wounds heal more slowly, and the risk of skin cancer increases. These are direct consequences of the structural changes in both skin layers.
The thinning can be partly slowed or even reversed. Daily creams containing retinoids (a group of vitamin A derivatives, available both over the counter and on prescription) can thicken the skin in both layers and reduce fine lines. A chemical peel showed a measurable increase in epidermal thickness in a small study of postmenopausal women. And a small Japanese RCT in sedentary middle-aged women found that strength training made the dermis thicker, while endurance training did not. It should be noted that three researchers involved in that strength training study had ties to a cosmetics company, so treat that result with some caution.
Based on two review studies (Michigan), a meta-analysis of 133 studies, several additional reviews, a small biopsy study (n=71), an RCT on strength training (n=56), and an RCT on chemical peeling (n=46). The evidence for the general direction (thinning skin) is solid; for the interventions it is moderate to limited.
Does your body odour change as you get older?
Yes, your body odour changes noticeably with age: from your forties onwards your skin produces a compound that adds a greasy, grassy note, and at the same time you become less able to perceive smells yourself.
Does your skin age faster than your organs?
It has not been proven that skin as an organ naturally ages faster than your internal organs, but it is more vulnerable to sun and other external stimuli that measurably raise biological age. Limiting UV exposure is the best-supported way to slow skin ageing.
Does sleep deprivation age your skin faster?
Sleep deprivation demonstrably worsens your hydration, elasticity, and wrinkles, after as little as one poor night. Aim for consistently adequate sleep, and combine it with sun protection for the best result.
Does menopause accelerate skin ageing?
Menopause noticeably accelerates the loss of collagen, moisture retention and skin thickness, but spots and skin cancer are almost certainly caused by sunlight. If you are experiencing skin complaints around menopause, discuss with your doctor whether HRT makes sense for you as an overall package.
Does chronically poor air quality age your skin?
Chronic exposure to air pollution measurably accelerates skin ageing, and the evidence for this is reasonably consistent. If you live or work in a structurally polluted environment, paying extra attention to your skin barrier (a good moisturiser, sun protection) is a worthwhile step.
Do people with dark skin age more slowly than people with light skin?
Dark skin ages more slowly in terms of visible sun damage, but ageing itself does not stay away: the signs are different, not absent. Protect your skin regardless of your skin colour, and with dark skin, pay attention to pigmentation spots as a sign of ageing.