• Draining blood from mice at regular two-week intervals improves their skin and reduces the prevalence of senescent cells, which underlie many age-related diseases.
  • Regular blood donations also lead to reduced skin iron content, which can drive a higher abundance of damaging, oxygen-containing molecules (reactive oxygen species).
  • Higher skin content of the anti-inflammatory protein, TGF-ß1, was also found after blood donations, suggesting a reduction in inflammation.

As we grow older, we often notice that our skin begins to sag, becoming rough and wrinkly. This can be attributed to a reduction in fibrous structural proteins called collagen and increased levels of collagen degradation. Finding ways to prevent skin aging entails wearing sunscreen to prevent sun damage and putting on skin moisturizer to reduce rigidity, with limited benefits. However, what if there were a simple, more effective way to reverse the ravages of skin aging and restore the skin’s collagen structure?

Published in Mechanisms of Ageing and Development, Zhang and colleagues from Nanjing University in China showed that bloodletting – draining blood – from mice improved their skin thickness and reduced the prevalence of aged, non-proliferating cells in skin. What’s more, draining blood from mice significantly reduced their blood iron content, increased levels of anti-inflammatory proteins in the blood, and increased the levels of fibrous, structural proteins called collagen. If these findings apply to humans, they could mean that people may use blood donations or other ways to drain blood from the body as skin anti-aging techniques.

Donating Blood Rejuvenates the Skin

To measure blood draining’s effects on the skin, Zhang and colleagues drained 0.1 mL or 0.2 mL of blood from the cheek of mice every two weeks for six weeks and found that it rejuvenated their skin thickness. The outer layer of the skin, the dermis, almost doubled in thickness with 0.2 mL drainage compared to no bloodletting. The fibrous structural collagen thickness, which keeps our skin firm, almost doubled, also. What’s more, the abundance of aged, non-proliferating senescent cells that release inflammatory proteins in cells to trigger inflammation in the skin diminished to about a third of what they were without donating blood. These findings provide strong evidence that bloodletting from mice improves the health of their skin and may confer anti-aging benefits.

(Liu et al., 2022 | Mechanisms of Ageing and Development) Draining blood from mice rejuvenates their skin. The images on the left show the thickness of the collagen layer of the skin (stained light blue). The graph in the middle quantitatively illustrates the findings from the images on the left, where draining 0.1 and 0.2 mL of blood almost doubled the structural collagen protein content of the skin (Figure D). Draining 0.2 mL of blood (BD 0.2) almost doubles the thickness of the collagen compared to no blood draining (BD 0). Blood draining also almost doubles the thickness of the most outer layer of the skin (dermis) with 0.2 mL of blood draining (BD 0.2 in Figure B) compared to no blood draining (BD 0 in Figure B).

Since iron deposition in skin has been shown to increase oxidative stress and because oxidative stress is linked to skin aging, Zhang and colleagues sought to find the effects of bloodletting on iron levels. They found that draining blood from the mice significantly reduced iron concentrations in the blood serum and the skin. Additionally, they found that levels of an anti-inflammatory protein, TGF-β1, increased in the blood and the skin, which may reduce skin inflammation.. These findings suggest that bloodletting allows blood and skin iron levels along with oxidative stress and inflammation to decline. 

(Liu et al., 2022 | Mechanisms of Ageing and Development) Blood draining reduces iron, inflammation, and senescent cells. Blood (serum) and skin iron content were significantly diminished by draining blood (Figure A). The anti-inflammatory protein TGF-β1 showed significantly increased levels in blood and skin after blood draining (Figure B). With blood draining, the abundance of senescent cells that contribute to skin inflammation and aging was more than halved (β-galactosidase-stained cells in Figure C).

Blood Donors Have Reduced Chances for Health Complications

“Our results also indicate the great potential for blood donation to be further developed as an anti-skin aging strategy, which may encourage the public to donate blood voluntarily,” said Zhang and colleagues.

Since mice typically have about 2 mL of blood circulating through their bodies, these bloodletting experiments withdrew about 5% to 10% of total blood. This measures up to about the typical blood withdrawal during a human blood donation, since humans typically carry 5 L of blood and donate 0.5 L (~10% of total blood in the body). Moreover, to translate the time equivalent skin anti-aging benefits from mice to humans, a person would need to have blood withdrawn about twice per year.

People who give regular blood donations have lower blood pressure, improved blood lipid profiles, and have lower risk of cardiovascular diseases. Maybe these benefits come from lower oxidative stress associated with getting rid of excessive iron in the blood in these individuals and/or reduced inflammation from a lower abundance of senescent cells in the skin. Nevertheless, the finding that blood donations may confer skin anti-aging benefits provides one more reason to visit blood donation clinics.