Acne is an inflammatory skin condition caused by blocked pores. It leads to redness, swelling, and sometimes pustules, which are inflamed bumps that contain pus (7).
In addition to breakouts, acne leaves many people with post-inflammatory scars and skin damage. However, research indicates that vitamin C may treat several of these conditions.
Keep in mind that while a high intake of foods rich in vitamin C may help other aspects of skin health, no research ties dietary vitamin C to reduced acne levels. Nonetheless, limited research suggests that the topical application of vitamin C may be helpful.
May reduce acne-related inflammation
Age, genetics, and hormones are risk factors for acne. Moreover, certain strains of the common skin bacterium Cutibacterium acnes (C. acnes) may trigger this condition (7, 8).
Given that vitamin C is anti-inflammatory, it may help reduce redness and swelling related to acne when used topically. Thus, it may improve the appearance of acne lesions (9).
In a 12-week study in 50 people, 61% of participants who used a lotion containing 5% sodium ascorbyl phosphate (SAP) — experienced significant improvements in acne lesions, compared with a control group (10).
In a smaller, 8-week study in 30 people, those who used 5% SAP had a 48.8% reduction in acne lesions. What’s more, those who used a combination of SAP and 2% retinol — a vitamin A derivative — had a 63.1% reduction (9).
Though these results are promising, larger high-quality studies are needed.
May improve the appearance of acne scars
After an acne breakout, your skin requires time to heal. Without proper healing, acne scars may develop.
Acne scars are usually related to severe, cystic acne, but they can result from mild cases as well. Moreover, prolonged acne, genetics, and physical manipulation like picking or squeezing can increase the likelihood of scarring (11).
The three main types of acne scars are atrophic, hypertrophic, and keloidal.
Atrophic scars cause a loss of skin tissue and collagen and appear as small indentions in the skin. Both hypertrophic and keloidal scars result from collagen overproduction and appear as thick, raised scar tissue (11).
Vitamin C treats acne scars by increasing the synthesis of collagen, a protein responsible for your skin’s structure and vital for rebuilding healthy skin. As a result, this vitamin may accelerate the healing of acne wounds (6, 12, 13).
A 4-week study in 30 people noted moderate improvements in acne scars after using microneedling — which involves rolling small needles over the skin to promote healing and increase collagen production — alongside a 15% vitamin C topical cream once per week (14).
Yet, it’s unknown if microneedling, vitamin C, or a combination of both was responsible for these results (14).
Moreover, vitamin C and microneedling are unsuitable for hypertrophic and keloidal scars, as these types result from collagen overproduction (15).
While no research links dietary vitamin C to reduced acne scarring, it increases your body’s natural collagen production and is still beneficial for overall skin health (16, 17).
May reduce hyperpigmentation
Hyperpigmentation is the formation of darkened spots on your skin as a result of acne, UV rays, or other injuries — though it should be noted that this condition is harmless.
Applying vitamin C to your skin may reduce hyperpigmentation by interfering with an enzyme called tyrosinase, which is responsible for the production of melanin, a natural skin pigment (12, 13, 18).
Moreover, vitamin C acts as a brightening agent and can reduce the appearance of darkened spots without changing the natural color of your skin (12, 13, 18).
Some human studies that combine topical vitamin C with iontophoresis — an electrical gradient applied to the skin — found significant reductions in hyperpigmentation (19, 20).
Though this method is promising, iontophoresis increases vitamin C absorption into your skin, meaning that topical application of vitamin C alone may not yield the same results (21).
Furthermore, most related studies use vitamin C in combination with other anti-hyperpigmentation ingredients like alpha-hydroxy acids, making it hard to determine the specific effects of the vitamin. Overall, more research is needed (21).
summary
Topical vitamin C may help reduce acne scars, as well as acne-related inflammation and hyperpigmentation. Still, most research suggests that combining it with other treatments yields the best results.