What is safer and the best option for me a BBL or Sculptra butt lift? (Photos)

Thanks for the question. 
In this regard, I recommend you waist and back Liposculpture, getting better curves especially in the waist, improving your body contour.
Finally, I suggested take the fat we get and transfer to the buttocks and hips, to mold them and get better volume, contour and butt projection, is that we know as "Brazilian Butt Lift" (BBL).
Kind regards

Thank you for your question and photos.  Based on your photos and BMI of 19, you do have limited amount of fat. As a Total Definer body sculpting surgeon, I would recommend VASER Hi Def Lipo 360 degrees with fat grafts to the buttocks. This is a technical and artistic operation. It is not enough to transfer fat to the buttocks without adequate sculpting of your torso. You have one good chance for this due to the limited fat supply.Sculptra injections are a waste of money (delicate results no visible improvement) and they do not sculpt the body.Regarding the statistic that you cited, that study is based on a survey (!), arbitrarily assigned a percentage of cases as being done by non-plastic surgeons (25%, but in reality it is close to 50%), they did not remove the outliers. One statistic included a surgeon who reported 9 deaths out of 10 BBLs he has ever done! Now who would go to someone like this person? or is this a misprint? They included deaths outside the study dates which further skewed the results. A new publication is in the works which refutes these numbers and is based on actual number of cases. It seems, that the death rate in BBL cases is 1:13,000! Death rate from abdominoplasties or tummy tucks is 1:10,000! No one raised any alarm about that.The safest choice you can make is choose a board certified plastic surgeon experienced in advanced body sculpting techniques for an in person consultation/evaluation. Good luck.See the attached web reference of a patient similar to your body habitus.

Dear Beautyresearch,
based on your photos, you look like a good candidate for a BBL. Liposuction of your abdomen, back and flanks should give you more curves and hourglass shape and fat transfer to buttocks should give you more projection. I would suggest you to consult a board-certified plastic surgeon because only after a thorough examination you will get more information and recommendations.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery