L-carnitine is not limited to its uses in nutrition and sports. It is increasingly being studied in dermatology, and some attribute to it the ability to strengthen hair anchorage and prevent hair loss. Myth or reality? Discover here whether the scientific literature supports this hypothesis.
L-carnitine: an ally for protecting hair against hair loss?
Published on October 1, 2025, updated on October 1, 2025, by Jamal, PhD, Doctor of human pathology and infectious diseases — 7 min of reading
Themes:
L-carnitine: a potential solution for hair loss?
Losing hair is a natural phenomenon: each day, it is normal to lose 50 to 100 hairs. This renewal is part of the hair follicle’s life cycle, which alternates between growth, rest, and shedding phases. But sometimes, hair shedding can intensify and become more noticeable, causing concern and prompting people to look for solutions. The causes include heredity, hormonal variations, stress, a poorly balanced diet, or even skin aging. If hair shedding is seldom a sign of a serious problem, yet it can significantly impact self-confidence and quality of life. That is why many people seek ways to strengthen their hair and protect it from shedding, such as with L-carnitine.
Several recent studies have investigated the role of L-carnitine in stimulating hair growth. One study in vitro evaluated the effect of L-carnitine-L-tartrate (referred to as CT in the study) on human hair follicles in the anagen phase, the active growth stage. The follicles were cultured for 9 days with varying concentrations of CT (0.5 to 50 µM). Results showed that follicles treated with moderate concentrations (0.5 and 5 µM) exhibited a significant stimulation of hair shaft elongation, with a 37% increase in hair length compared to the control group.
Hair shaft elongation in millimeters (a) and as a percentage (b) after treatment of hair follicles with different concentrations of L-carnitine-L-tartrate.
Source: PAUS R. & al. L-carnitine-L-tartrate promotes human hair growth in vitro. Experimental Dermatology (2007).
4 minutes to understand your skin. Our dermatological diagnostic guides you toward the ideal skincare for your specific needs. Simple, quick, personalized.
The study also showed that L-carnitine acts directly on the keratinocytes of the hair follicle by promoting their proliferation and inhibiting their apoptosis, that is, their programmed cell death. Histological analyses revealed a significant reduction in apoptotic cells and a slight increase in proliferating cells in the hair matrix of the treated follicles. This cellular modulation prolongs the anagen phase, thereby enabling more sustained hair growth. These early results in vitro, to be confirmed in clinical trials, support the rationale for L-carnitine in topical application or oral administration to strengthen the hair.
Research on L-carnitine is not limited to this single study in vitro. A nine-month clinical trial evaluated the effectiveness of L-carnitine in reducing hair loss and improving scalp health. Four groups of 20 participants each were formed: the first group received an oral L-carnitine supplement, the second applied a topical lotion containing L-carnitine, the third combined both the supplement and the lotion, and the fourth served as the untreated control group. In total, 79 participants completed the study.
| Active | Oral supplement | Topical lotion |
|---|---|---|
| L-carnitine | 544 mg | Present (> 2%) |
| L-leucine | 150 mg | Present |
| L-isoleucine | 75 mg | Present |
| L-valine | 75 mg | Present |
| Potassium | 100 mg | Present |
| Nicotinamide | 40 mg | Present |
| Zinc | 15 mg | Present |
| Biotin | 150 µg | Present |
| Selenium | 75 µg | Absent |
| Methylsulfonylmethane (MSM) | Absent | Present |
Composition of the oral supplement and topical lotion.
Source: BAYER M. & al. The effect of a food supplement and a hair lotion on the progression of androgenetic alopecia. Journal of Cosmetics, Dermatological Sciences and Applications (2019).
After nine months, all treated groups showed a significant reduction in hair loss, unlike the control group, which recorded an average 23.7% increase in shedding. The mean reductions in the treated groups were –35.4% for the supplement, –38.8% for the lotion, and –31.0% for the supplement-plus-lotion combination. Moreover, 75% of participants in the treated groups reported decreased shedding, and 67% perceived their hair as healthier by the end of the study.
The study also demonstrated that L-carnitine–based products increased the ratio of hairs in the anagen (growth) phase to those in the telogen (shedding) phase. The treated groups exhibited an average improvement in this ratio of +55.1% (supplement), +39.4% (lotion), and +63.5% (combination), whereas the control group experienced a slight decrease of –3.9%. No adverse effects were observed, confirming the good tolerability of the formulations.
Effects of oral, topical, or combined L-carnitine supplementation on hair loss (a) and the ratio of anagen-phase to telogen-phase hairs (b).
Source: BAYER M. & al. The effect of a food supplement and a hair lotion on the progression of androgenetic alopecia. Journal of Cosmetics, Dermatological Sciences and Applications (2019).
The results obtained with L-carnitine are encouraging and suggest that it may help combat hair loss.
However, since the clinical trial combines several active ingredients with complementary properties, it is difficult to attribute the observed benefits specifically to L-carnitine. Therefore, it is necessary to remain cautious and to pursue further research by conducting larger-scale clinical studies that better isolate the effect of L-carnitine, in order to confirm its potential benefit in cases of hair loss.
Sources
PAUS R. & al. L-carnitine-L-tartrate promotes human hair growth in vitro. Experimental Dermatology (2007).
PEDRE-PINEIRO A. M. & al. Significance of L-carnitine for human health. IUBMB Life (2017).
BAYER M. & al. The effect of a food supplement and a hair lotion on the progression of androgenetic alopecia. Journal of Cosmetics, Dermatological Sciences and Applications (2019).
CONSOLARO F. & al. A liposome-based formulation containing equol, dihomo-γ-linolenic acid and propionyl-L-carnitine to prevent and treat hair loss: A prospective investigation. Dermatologic Therapy (2019).
ASBAGHI O. & al. The effects of L-carnitine supplementation on inflammatory and anti-inflammatory markers in adults: A systematic review and dose-response meta-analysis. Inflammopharmacology (2023).
