Where do brown spots on the hands come from, and how can they be removed?

The brown spots that appear on the hands are not only a consequence of the passage of time.

They result primarily from the interaction between intrinsic skin aging and repeated exposure to sunlight. The hands are among the most sun-exposed areas on a daily basis, often without adequate protection, which promotes the gradual development of uneven pigmentation.

For a long time, these spots were mainly thought to be caused by local overproduction of melanin. In reality, their formation appears to be more complex. Of course, melanocytes, the cells that produce melanin during melanogenesis, are involved in the process, but recent data show that the problem is not just an excessive activation of these cells. In solar lentigines, melanin also accumulates because its elimination becomes less efficient. In other words, the skin is no longer as effective at distributing and clearing the pigment toward the surface, which promotes its retention in certain areas.

This pigmentation disorder can be explained largely by the progressive transformations of the epidermis. Under the effect of photoaging, keratinocytes, which make up most of this superficial layer, no longer renew themselves in such a well-organized manner. Several studies have shown that basal keratinocytes proliferate more, while the cells above them desquamate more slowly. This imbalance alters the architecture of the epidermis and promotes the formation of elongated epidermal ridges. These microscopic deformations disrupt the normal upward migration of melanin toward the skin surface, which contributes to its local accumulation and to the darker appearance of the lesion.

The dermis is also involved in this process. With age and chronic sun exposure, the fibroblasts, which are responsible for producing collagen and elastin, become less functional and can enter a state of senescence. They then secrete higher levels of inflammatory mediators, metalloproteinases, and signaling factors capable of influencing pigment activity. At the same time, UV radiation, by inducing significant oxidative stress, activates various inflammatory signaling pathways and disrupts the normal communication between keratinocytes, melanocytes, fibroblasts, and even endothelial cells.

Brown spots on the hands result from a collective dysfunction of skin cells, rather than just a simple excess of melanin.

Of course, genetics plays a major role in these processes. Variants of the MC1R gene, well known for their role in the response to sunlight, modulate the activation of melanogenesis via the α-MSH/cAMP pathway, while genes such as MITF and TYR directly regulate melanin synthesis within melanocytes. Other genes involved in managing oxidative stress, such as those regulated by the NRF2 pathway, determine the ability of skin cells to neutralize free radicals. Thus, even with the same level of sun exposure, not all individuals necessarily develop brown spots on their hands.

Among the first visible signs of skin aging or chronic sun exposure, dark spots on the hands can be a source of cosmetic discomfort. Before considering more invasive medical procedures, certain cosmetic active ingredients can visibly reduce their appearance. By targeting the excessive production of melanin or promoting the exfoliation of pigmented cells, these ingredients provide a gradual yet effective approach to evening out the appearance of the hands and helping prevent new spots from forming.

• The vitamin C.

  Vitamin C, or ascorbic acid, is one of the most extensively studied active ingredients for its brightening effect on pigment spots. It works by inhibiting the activity of tyrosinase, the enzyme that catalyzes the conversion of tyrosine into melanin in the skin. In addition, its antioxidant properties allow it to neutralize free radicals generated by UV radiation or pollution, which also stimulate melanogenesis. When used regularly on the backs of the hands in the form of a serum or cream, vitamin C can help reduce the appearance of pigment spots.

  A recent study evaluated the effectiveness of a serum containing 15% pure vitamin C, 1% vitamin E, and 0.5% ferulic acid on pigmented spots on the backs of the hands in 60 volunteers aged 40 to 80 years. Applied twice daily for six months, this treatment proved effective in improving the uniformity of hand color. Vitamin C, when combined with other antioxidants such as ferulic acid and vitamin E, therefore appears to be a promising option for reducing hyperpigmentation.

• The azelaic acid and the glycolic acid.

  Azelaic acid is a naturally derived active ingredient with depigmenting properties that are useful for reducing dark spots on the hands. It also works by inhibiting the activity of the enzyme tyrosinase and has anti-inflammatory and antioxidant actions, enabling it to target different types of hyperpigmentation, including post-inflammatory marks. Glycolic acid, for its part, is an AHA known for its exfoliating effects, allowing it to remove melanin-loaded cells at the skin’s surface. It also speeds up cell turnover in the basal layer of the skin, the deepest layer of the epidermis, where the melanocytes that produce melanin are located.

  A 24-week study was conducted in 60 patients with melasma. Although the condition did not involve the hands, the underlying pigmentation mechanisms are comparable. The participants were divided into two groups. The first group received a 30% glycolic acid peel every three weeks, in addition to twice-daily application of a cream containing 20% azelaic acid. The second group used the cream alone. Evaluation was based on the MASI (Melasma Area and Severity Index) score. While improvement was observed in both groups, the reduction in MASI score was significantly greater in patients who received the combination of glycolic acid and azelaic acid.

• The arbutin acid (or alpha-arbutin).

  Often described as a natural hydroquinone, the remarkable effectiveness of arbutin acid against dark spots is due to its affinity for the active site of tyrosinase. Arbutin acid acts through competitive inhibition : by binding to the active site of the enzyme, it blocks its activity and, consequently, melanin synthesis. A study conducted in India on 36 women with dark spots demonstrated the depigmenting properties of arbutin acid.

  For 56 days, the participants applied twice daily a cream containing 10% 3,4,5‑trihydroxybenzoic glucoside (THBG) and 2% α‑arbutin, in addition to using a SPF 50+ sunscreen once per day. The effectiveness of the protocol was evaluated with a mexameter, which measures melanin content, and the MASI score. The results showed a significant reduction in skin pigmentation and in the MASI score, with no adverse side effects observed.

• The licorice extract.

  Under its INCI name Glycyrrhiza Glabra Root Extract, licorice extract contains 95% glabridin, a compound involved at multiple levels in regulating the process of hyperpigmentation. It significantly reduces the amount of endothelin-1, a mediator involved in melanogenesis that is released by keratinocytes after UV exposure. In addition, licorice extract inhibits the activity of phospholipase A2 (PLA2), an enzyme released by epidermal keratinocytes after UV exposure or during inflammation, which stimulates tyrosinase activity and thus melanin production. However, to date, the depigmenting effects of licorice extract have only been demonstrated in vitro.

• The tranexamic acid.

  Tranexamic acid is a synthetic derivative of lysine, an amino acid found in the skin. This active ingredient acts on hyperpigmentation by blocking the interaction between keratinocytes and melanocytes, and by competitively inhibiting the active site of tyrosinase, which blocks its activity and, consequently, the synthesis of melanin.

  Several studies have demonstrated the benefits of tranexamic acid in cases of dark spots. A recent study evaluated the effectiveness of a serum and a cream formulated with 3% tranexamic acid to reduce hyperpigmentation in 22 individuals aged 45 to 67 years. After eight weeks of daily application, a significant 13% reduction in the colorimetric intensity of the spots and a 6% reduction in their size were observed. In addition, 77% of participants reported a visible decrease in their spots.

Even though certain cosmetic active ingredients can help reduce dark spots, their effects remain gradual and limited. In cases of pronounced hyperpigmentation, only aesthetic medicine can provide rapid and visible results.

As a first-line approach, laser treatment is one of the most effective solutions for brown spots on the hands. Among the most commonly used techniques are Q-switched lasers, IPL (intense pulsed light), and non-ablative fractional lasers. These devices specifically target the melanin contained in the spots : the light energy emitted by the laser is absorbed by clusters of pigment, which leads to their fragmentation into smaller particles that the body will gradually eliminate. One to three sessions, spaced several weeks apart, are generally sufficient to observe a clear improvement. The procedure is quick and minimally invasive, but it can cause some temporary side effects, such as redness or scab formation.

The results obtained with a laser are often very satisfactory, but they require a thorough prior dermatological evaluation to rule out any suspicious lesions and to adapt the protocol to the patient’s skin phototype.

A recent study evaluated the effectiveness of intense pulsed light on brown spots on the backs of the hands in 15 participants aged 40 to 73 years, treated in three monthly sessions. Follow-up was performed one and three months after the last session, with image analyses via the VISIA system, a digital imaging system used in dermatology and aesthetic medicine. The results, presented in the table below, show a significant decrease in the number of brown spots, as well as in their intensity and contrast.

Another aesthetic medicine option is professional chemical peels. These are based on the same principle as cosmetic exfoliating treatments but use higher concentrations. Among the most commonly used active ingredients are glycolic acid, trichloroacetic acid (TCA), and lactic acid, used alone or in combination. The goal is to induce shedding of the superficial layers of the epidermis that contain clusters of melanin, while stimulating the production of more uniform skin cells. Depending on the depth of the peel, it may be necessary to avoid social activities for several days. Multiple sessions are often required, and again, a prior evaluation by a healthcare professional is necessary to validate the protocol and ensure that it is appropriate for the individual situation.

Prevention is better than cure: to avoid dark spots on the hands, it is recommended to protect them daily with a sunscreen.

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