Citrulline
An amino acid. It works as a moisturizing conditioner and part of the skin natural moisturizing factor. Well tolerated.
Evidence by route
Topical application
An amino-acid humectant. Safe.
- CIR Cosmetic Ingredient Review safety assessment
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Citrulline is a non-essential amino acid. On the label it reads Citrulline. In cosmetics it works as a humectant and conditioner: it draws and holds water in the stratum corneum and is part of the skin's natural moisturising factor, which helps keep skin supple. On efficacy it is a simple, honest hydrating active. It does not work age-related miracles or rebuild the dermis, but as a moisturising agent and part of the NMF it gives a real gain in comfort and softness. It performs better inside a well-built formula than on its own. For pregnancy and breastfeeding there is no restriction. It is a physiological molecule and its topical use carries no meaningful systemic impact, so it can be applied. Tolerance is very good. Irritation and allergy are low, which suits sensitive and reactive skin. Being an amino acid native to the body, it rarely causes trouble.
Frequently asked questions
Is Citrulline safe during pregnancy?
Citrulline is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Citrulline for?
Citrulline suits: normal, dry, combination, oily, sensitive.
What is Citrulline and what does it do in cosmetics?
An amino acid.
What's the INCI name for Citrulline?
The INCI name is Citrulline.
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