An interesting dive on what hygral fatigue is and the supporting evidence as well as the evidence against it.
Sarah Ingle video
Afobe Atoyebi video
Science-y hair blog article
Sura Kamil blog article
Secondary Ion Mass Spectrometric investigation of penetration of coconut oil and mineral oils into human hair fibers: Relevance to hair damage” Published in Journal of Cosmetic Science , 2001 , Volume 52 , Issue 3 , pp. 169–184
Lee Y, Kim YD, Hyun HJ, Pi LQ, Jin X, Lee WS. Hair shaft damage from heat and drying time of hair dryer. Ann Dermatol. 2011 Nov;23(4):455-62. doi: 10.5021/ad.2011.23.4.455. Epub 2011 Nov 3. PMID: 22148012; PMCID: PMC3229938.
Stam PB, Kratz RF, White HJ. The Swelling of Human Hair in Water and Water Vapor. Textile Research Journal. 1952;22(7):448-465. doi:10.1177/004051755202200702
(Couldn't find a free link to this one)
Gamez-Garcia, M. The cracking of human hair cuticles by cyclical thermal stresses. 1998 May. Journal of the Society of Cosmetic Chemists 49(3):141-153
Yang FC, Zhang Y, Rheinstädter MC. The structure of people's hair. PeerJ. 2014 Oct 14;2:e619. doi: 10.7717/peerj.619. PMID: 25332846; PMCID: PMC4201279.
Franbourg A, Hallegot P, Baltenneck F, Toutain C, Leroy F. Current research on ethnic hair. J Am Acad Dermatol. 2003 Jun;48(6 Suppl):S115-9. doi: 10.1067/mjd.2003.277. PMID: 12789163.