When people talk about "heat training," they're typically referring to the process of repeatedly straightening natural hair with heat in an effort to make their tresses less textured over time. Most often, training is achieved with a hot comb, old-fashioned Marcel iron or, most commonly, a flat iron. Repeated heat styling will loosen hair's curly texture over time by breaking down bonds; it can be considered "controlled damage." The reason it's controlled damage instead of just damage is that heat training black hair is a gradual process. What you're not trying to do is apply too-high temperatures in one straightening session. Yeah, the hair probably won't revert back to its curly state, but it'll also be brittle and dry, and just break off. You choose.
Anyone with highly textured curls knows that trying to straighten them, especially in high-humidity climates, is usually if not always an exercise in frustration. Your hair might look fabulous right after ironing it, but once you step outside the door (or even stand in a steamy bathroom), your work might just go, "poof."
Some women, therefore, turn to heat training, doing it on a regular basis. They might do this anywhere from once a week to once every few weeks. Over time, the hydrogen bonds in the hair weaken, so hair becomes less and less likely to revert. Extremely high heat isn't necessary—it's the repeated act of heat application that wears these bonds down.
If you only occasionally straighten your natural hair, this probably won't be something you want to try, as the effects are usually permanent. In some cases, you might be able to treat hair's weakened hydrogen bonds with protein, but if the bonds are damaged beyond repair, you'll notice. One of the most visible signs of heat-damaged hair is over-porosity. Over-porous hair dries very quickly when water is applied, has curls that don't "snap back" readily when you gently pull on them, or even has lost the ability to hold its natural curl.
Women who want to train their hair aren't bothered by this, but it's not the healthiest state for your hair to be in. Although more modern relaxer formulations and newer straightening methods like keratin treatments are widely available, plenty of people choose not to put chemical straighteners on their heads. They may have medical issues that make relaxing dangerous, or might want to avoid the chemicals. At the same time they might still want to wear their hair straight, either for ease or just style preference.
So, should you do it? If you do choose to train your hair, remember that it's called "training" for a reason—curly and coily textures don't easily succumb to attempts to change them unless strong chemicals are involved. You can lessen the chance of damage, but not escape it entirely, with this kind of frequent heat exposure. Make sure to:
- Condition and deep condition your mane on a regular basis; weekly deep conditioning is recommended. Neutrogena's Triple Moisture Deep Recovery Hair Mask ($6) works wonders.
- Use a high-quality heat protectant during every straightening session. We like Moroccanoil's Perfect Defense Heat Protectant ($28).
- Alternate thermal styling with heat-free straightening methods.
Wrap your hair at night to preserve the style and reduce the need for "bumping" with heat during the day.
Even with all these precautions in place, repeated heat styling will weaken the hair's hydrogen bonds, so only heat train your hair if you're positive you can live with the results, whatever they may be.