There are many heat-protectant products available on the market, so you can find one that fits your hair type and needs. In case you really need to use heat to curl hair extensions, be knowledgeable about some products like heat protectant sprays, leave-in conditioners, hair oils, creams, lotions, and any other concentrated dose of hydration products. Reapply the heat protectant if you are using heat styling tools for an extended amount of time. Read more about how to keep hair from getting greasy.