Definition Guide for skin and hair care terms. A to Z Glossary of hair & skin ingredients with effective results. Updated regularly.
- L-Ascorbic Acid
- L-Ascorbic Acid is a potent form of Vitamin C. It is fresh and concentrated. L-ascorbic acid is a vitamin C that can be applied as a topical skin treatment. Vitamin C is the only antioxidant proven to stimulate collagen production.
- L-Cysteine is necessary to build Keratin. Hair is 14% cysteine. It is included in some hair growth supplements.
- L-Methionine is for hair structure and strength. It is included in some hair supplements to prevent hair breakage and thinning mid-length.
- Lactic acid
- Lactic acid exfoliates and brightens skin. It is gentler than glycolic acid. Lactic acid holds moisture while increasing firmness and skin thickness.
- Lanolin is a natural oil from sheep’s wool. It is easily absorbed and protects and soothes skin. Commonly used in lip balms and moisturizers.
Lavender Essential Oil
- Lavender Oil softens and conditions the hair and skin. Lavender’s anti-microbial and anti-bacterial properties keep skin and the scalp healthy. It has soothing properties to calm any scalp imbalances such as inflammation or dry skin flaking. This is beneficial to remove dry skin patches where DHT might accumulate. The linalyl acetate in lavender enhances cell growth in skin and hair. Some lab studies show promise in lavender inducing faster hair growth. 
- Age spots.
- Licorice Root
Licorice root benefits skin and hair. Licorice root contains glabridin, is a potent antioxidant that soothes skin. It lightens dark circles gently, improves uneven tone and skin redness. it is safe for even sensitive skin.  Licorice Root Extract has hair regrowth capabilities. A study showed the Licorice Root infusion safely treated Alopecia with better clinical results than Minoxidil.  Licorice root is an excellent scalp moisturizer you since it preserves the natural oils of the hair and does not dry out your scalp. Licorice Root extract also treats chemical hair damage with gentle moisturizing properties while leaving hair silky.
- Lime Peel Oil
- Lime Peel Oil is formally known as Citrus Aurantifolia. Lime Peel Oil
is an antioxidant. It has skin-toning properties and can fade discoloration. Lime Peel Oil is particularly effective when used in a formulation with multiple moisturizing buffers, but it is quite powerful and can be too strong for sensitive skin. When using Lime Peel Oil, dilute with a soothing carrier oil or buffering cream.
- Lingonberry Stem Cells
Lingonberry stem cells increase natural antioxidant mechanisms in skin cells. This decreases skin irritation and inflammation. Lingonberry is a “superfruit”. It is rich in vitamins C and E, both excellent for repairing and preventing sun damage.
- Linoleic acid
- Linoleic acid (Vitamin F) is an omega-6 fatty acid with skin barrier-strengthening, healing, hydrating and anti-inflammatory properties.
- Linseed Oil
- Linseed Oil helps hair damaged by styling tools. High in Omega 3s, Linseed can be massaged into the scalp to nourish the hair for new growth, and restore damaged hair.
- Lee BH, Lee JS, Kim YC. “Hair Growth-Promoting Effects of Lavender Oil in C57BL/6 Mice.” ToxicolRes 2016;32:103-108.
- Natural Product Research, December 2007, pages 1,234-1,239
- Deb Roy, Saumendu & Karmakar, Prithivi & Dash, Suvakanta & Jashabir, Chakraborty & Biswajit, Das. (2014). HAIR GROWTH STIMULATING EFFECT AND PHYTOCHEMICAL EVALUATION OF HYDRO-ALCOHOLIC EXTRACT OF GLYCYRRHIZA GLABRA. Global Journal of Research in Medicinal Plants and Indigenous Medicines. 3. 40-47.