Some natural ways to straighten hair without the use of chemical treatments and heated tools include hot oil, milk and coconut milk. Other methods involve using eggs and olive oil, Fuller's Earth or aloe vera. Remedies with these ingredients should be performed two to three times a week.
Natural methods of hair straightening arise generally out of legitimate concern for the damage that chemical treatments and heated tools can cause to hair. The most common side effects of straightening via heated tools and chemical straightening products are dryness and frizz; however, chemical products in particular have been shown to have more significant negative side effects. Chemical straightening products use chemicals to change the way that molecules of keratin, the primary protein of which strands of hair are composed, interact with one another. By using a combination of keratin and formaldehyde or other "aldehyde" chemicals in the same family, chemical straightening products create a reaction that flattens hair. The danger associated with these ingredients is the emission of formaldehyde from the treated hair, which is more prevalent if the hair treatment must be left in for multiple days. The effects of formaldehyde emission may include allergic response, irritation and cellular damage.