In Latin, vernix means varnish and caseosa means cheesy.
Vernix has a highly variable makeup but is primarily composed of sebum, cells that have sloughed off the fetus's skin and shed lanugo hair. 12% of the dry weight of vernix is branched-chain fatty acid-containing lipids, cholesterol and ceramide. Vernix of term infants has more squalene and a higher wax ester to sterol ester ratio than preterm infants.
|Lipid fractions||Vernix caseosa lipids||Stratum corneum lipids||Skin surface lipids|
|Free fatty acids||6.5||25.0||18.4|
Cells of vernix are tyically polygonal or ovoid in shape and lack nucleus. Nuclear ghosts are frequently observed. Vernix corneocytes lack desmosomal attachment and this distinguishes them from corneuocytes found in mature stratum corneum. Thickness of a corneocyte is 1-2 µm. These cells are surrounded by layer of amorphous lipids lacking typical lamellar architecture present in mature stratum corneum.
Physical properties 
Vernix is not uniformly distributed, but rather present in form of cellular sponges. The critical surface tension of vernix is 39 dyne/cm. Despite its water content (82%), vernix is nonpolar. These features point towards the "waterproofing" function of vernix, thereby preventing heat loss soon after birth.
Biological properties 
Vernix provides electrical isolation for the fetus, which is presumably important aspect of developing fetal anatomy. Early scientific studies indicated increased evaporative heat loss in infants when vernix was removed soon after birth; but newer reports confirm that washing skin surface after birth reduces evaporative water losses compared to surface of newborns in which vernix is left in situ.  Vernix is hydrophobic.
The sebum in vernix is produced in utero by the sebaceous glands around the 20th week of gestation. Vernix appears primarily in full term infants, while premature and postmature births generally lack any. Postdates desquamation (flakey skin in babies born >42 weeks) is thought to be due to loss of vernix.
Vernix is theorized to serve several purposes, including moisturizing the infant's skin, and facilitating passage through the birth canal. It serves to conserve heat and protect the delicate newborn skin from environmental stress. Vernix is also thought to have an antibacterial effect; though there is little evidence to support a chemical role of vernix in protecting the infant from infection, it may form a physical barrier to the passage of bacteria.
Additional images 
- Schachner, Lawrence A.; Hansen, Ronald C. (2003). Pediatric dermatology. St. Louis: Mosby. pp. 206–7. ISBN 978-0-323-02611-6.
- Ran-Ressler, Rinat R; Devapatla, Srisatish; Lawrence, Peter; Brenna, J Thomas (2008). "Branched Chain Fatty Acids Are Constituents of the Normal Healthy Newborn Gastrointestinal Tract". Pediatric Research 64 (6): 605–9. doi:10.1203/PDR.0b013e318184d2e6. PMC 2662770. PMID 18614964.
- Sumida Y, Yakumaru M, Tokitsu Y, et al. Studies on the function of Vernix caseosa: The secrecy of Baby's skin. Cannes, France: International Federation of the Societies of Cosmetic Chemists 20th International Conference; 1998. pp. 1–7.
- Hoath, Steven (2003). Neonatal skin : structure and function (2. ed., rev. and expanded. ed.). New York [u.a.]: Dekker. pp. 193–208. ISBN 0-8247-0887-3.
- Baker, SM; Balo, NN; Abdel Aziz, FT (1995 Mar-Apr). "Is vernix caseosa a protective material to the newborn? A biochemical approach.". Indian journal of pediatrics 62 (2): 237–9. PMID 10829874.
- Pickens, WL; Warner, RR; Boissy, YL; Boissy, RE; Hoath, SB (2000 Nov). "Characterization of vernix caseosa: water content, morphology, and elemental analysis.". The Journal of investigative dermatology 115 (5): 875–81. PMID 11069626.
- Youssef, W; Wickett, RR; Hoath, SB (2001 Feb). "Surface free energy characterization of vernix caseosa. Potential role in waterproofing the newborn infant.". Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) 7 (1): 10–7. PMID 11301635.
- Wakai, RT; Lengle, JM; Leuthold, AC (2000 Jul). "Transmission of electric and magnetic foetal cardiac signals in a case of ectopia cordis: the dominant role of the vernix. caseosa.". Physics in medicine and biology 45 (7): 1989–95. PMID 10943933.
- Saunders C. The vernix caseosa and subnormal temperature in premature infants. Br J Obstet Gynaecol 1948; 55:442–444
- Riesenfeld B, Stromberg B, Sedin G. The influence of vernix caseosa on water transport through semipermeable membranes and the skin of full-term infants. Neonatal Physiological Measurements: Proceedings of the Second International Conference on Fetal and Neonatal Physiological Measurements, 1984:3–6.
Further reading 
|Wikimedia Commons has media related to: Vernix caseosa|
- Sarkar, Rashmi; Basu, Srikanta; Agrawal, R K; Gupta, Piyush (2010). "Skin Care for the Newborn". Indian Pediatrics 47 (7): 593–8. doi:10.1007/s13312-010-0132-0. PMID 20683112.
- Visscher, Marty O; Narendran, Vivek; Pickens, William L; Laruffa, Angela A; Meinzen-Derr, Jareen; Allen, Kathleen; Hoath, Steven B (2005). "Vernix Caseosa in Neonatal Adaptation". Journal of Perinatology 25 (7): 440–6. doi:10.1038/sj.jp.7211305. PMID 15830002.
- Haubrich, Kathleen A. (2003). "Role of Vernix Caseosa in the Neonate: Potential Application in the Adult Population". AACN Advanced Critical Care 14 (4): 457–64. PMID 14595204.