A keratin treatment is not better than a hair spa in general—they are different things: a keratin treatment is used to control frizz and smooth the hair for a long time, while a hair spa provides nourishment and a healthy scalp. So, pick one according to your hair type, the result you want, and the amount of maintenance you can do.
Hair spas are all about hydration, repairing, and relaxation, and they usually contain very few chemicals, which makes them the perfect treatment for dry, damaged, or weak hair. Besides the massage, which improves blood flow, people wear hydrating masks, as they bring back the softness and shine of the hair, which lasts for 1-2 weeks. As no hair texture is changed, it is suitable for all hair types, even those with sensitive scalps.
Keratin works to smooth the hair by filling the protein lost in the hair structure, thus getting rid of frizz, and it helps to straighten the hair a bit, as well as making it more manageable for the next 3-6 months. The best solution for hairy heads that are curly, frizzy, or suffer from the effects of the humidity is a keratin treatment, which also makes the hair dry quicker and lessens the hair breakage. It is a heat-sealed treatment, so, to make it more durable, care with a sulfate-free shampoo is needed.
Use a hair spa when you want a quick pick-me-up, suffering from dandruff, or getting your hair ready for a keratin treatment—regularly, once a month, to maintain the hair. In case of a daily fight with frizz and a wish for a quick and long-term solution, keratin is the answer; however, on damaged hair, it is better not to do that. One can also do both treatments: first, get a spa treatment that will make the hair healthier, then a keratin one.