Usage
Lactic acid, an alpha-hydroxy acid (AHA), is primarily used topically for dry skin. It exfoliates by removing dead skin cells from the stratum corneum and promotes skin hydration. While used for other skin conditions like acne, aging skin, warts, and canker sores, scientific evidence supporting these uses is limited. Orally, lactic acid is present in fermented foods, but its medicinal use in this form lacks sufficient safety and efficacy data. It is also used vaginally as a contraceptive.
Alternate Names
- 2-Hydroxypropionic acid
- Acide 2-hydroxypropionique
- Lac-Hydrin (brand name for ammonium lactate cream)
- Phexxi (brand name for lactic acid/citric acid/potassium bitartrate vaginal gel)
How It Works
Topical: Lactic acid acts as a humectant, drawing moisture into the skin. It reduces corneocyte cohesion, facilitating exfoliation. The exact mechanism is not fully understood but may involve disrupting the bonds between dead skin cells. It appears to thicken deeper skin layers, potentially improving firmness. Absorption is minimal with topical application.
Vaginal: When used vaginally as a contraceptive, the combination of lactic acid, citric acid, and potassium bitartrate maintains vaginal pH in an acidic range which decreases sperm motility.
Dosage
Standard Dosage
Adults (Topical):
- Creams/lotions: Apply to affected area twice daily. Concentrations up to 10% are considered safe for facial use, while concentrations up to 15% can be used on the body.
- Higher concentrations (above 15%) should only be used under dermatological supervision.
Children (Topical):
- Safety and efficacy established in children as young as 2 years old.
- Follow product-specific guidelines or consult a dermatologist for appropriate concentrations and application frequency.
Special Cases (Topical):
- Elderly Patients: No specific dosage adjustments are generally needed but caution is advised, especially with higher concentrations.
- Renal/Hepatic Impairment: No dose adjustments are typically required for topical use.
- Pregnant/Breastfeeding: Topical use is generally considered safe during pregnancy and breastfeeding in concentrations below 10%. Vaginal use has not been studied and should be avoided.
Clinical Use Cases
Dosage is primarily relevant for topical preparations. Specific medical settings for other routes of administration lack sufficient clinical data.
Dosage Adjustments
Adjustments may be needed for patients with sensitive skin. Start with lower concentrations and increase gradually as tolerated. Discontinue if irritation persists.
Side Effects
Common Side Effects (Topical)
- Burning
- Stinging
- Itching
- Redness (erythema)
- Peeling
Rare but Serious Side Effects (Topical)
Severe skin irritation (with high concentrations)
Long-Term Effects
No significant long-term effects are reported with topical use within recommended concentrations.
Contraindications
- Hypersensitivity to lactic acid or any component of the formulation.
- Active eczema, psoriasis, or rosacea (for topical peels)
Drug Interactions
Topical: Limited information on drug interactions is available. Concomitant use with other topical medications, especially exfoliants, may increase the risk of irritation.
Vaginal: Do not use with contraceptive vaginal rings.
Pregnancy and Breastfeeding
Topical lactic acid (concentrations below 10%) is considered likely safe during pregnancy and breastfeeding. Lactic acid is a normal component of breast milk, and levels may increase after intense exercise without apparent harm to infants. Vaginal use as a contraceptive has not been studied during pregnancy or breastfeeding.
Drug Profile Summary
- Mechanism of Action: Exfoliates dead skin cells, hydrates skin.
- Side Effects: Burning, stinging, itching, redness, peeling (topical).
- Contraindications: Hypersensitivity to lactic acid.
- Drug Interactions: Limited information available (topical), do not use vaginally with contraceptive rings.
- Pregnancy & Breastfeeding: Topical use generally safe in low concentrations. Vaginal use not studied.
- Dosage: Topical: Apply twice daily, concentrations vary.
- Monitoring Parameters: Monitor for skin irritation with topical use.
Popular Combinations
Combined with other AHAs in some skincare products for enhanced exfoliation.
Precautions
- Test on a small skin area before widespread application.
- Avoid contact with eyes and mucous membranes.
- Use sunscreen during the day when using AHAs, as they can increase sun sensitivity.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Lactic Acid?
A: For topical use, apply creams or lotions twice daily. Concentrations vary depending on the product and the area of application (face: up to 10%, body: up to 15%).
Q2: Can lactic acid be used during pregnancy?
A: Topical lactic acid in low concentrations (below 10%) is generally considered safe during pregnancy. Consult a healthcare professional for personalized advice.
Q3: What are the common side effects of lactic acid?
A: Common side effects of topical lactic acid include mild burning, stinging, itching, redness, and peeling.
Q4: How does lactic acid work for dry skin?
A: Lactic acid acts as a humectant, attracting and retaining moisture in the skin. It also helps exfoliate dead skin cells, revealing smoother, hydrated skin underneath.
Q5: Can lactic acid be used on the face?
A: Yes, lactic acid can be used on the face, but it is essential to start with a lower concentration (around 5%) to assess tolerance and gradually increase as needed.
Q6: Is lactic acid the same as other AHAs?
A: Lactic acid is a type of AHA, but it is not the same as other AHAs like glycolic acid or citric acid. They have similar but not identical properties and effects on the skin.
Q7: How long does it take to see results with lactic acid?
A: Improvement in skin dryness can be seen within a few days of regular use, but optimal results may take several weeks of consistent application.
Q8: Can lactic acid interact with other skincare products?
A: Combining lactic acid with other exfoliating products or retinoids may increase the risk of skin irritation. It’s best to consult a dermatologist before combining potent skincare ingredients.
Q9: What should I do if I experience excessive burning or irritation?
A: Discontinue use and consult a healthcare professional if excessive burning or irritation occurs. They can assess the reaction and recommend appropriate management.
